Abstract:
A coupon fabrication with defined distortion in the form of marceled fibers and test protocol is employed to determine the shape of the failure probability density curve to improve the analyses of the risk of fiber distortion anomalies in composite structures. This protocol provides a method to determine the probability of and the severity of the various distorted fiber conditions that might exist on composite structure in fabrication and in service. A distortion characterization matrix is established for determining test shapes and providing defect characterization based on the results of tests on the selected shapes. Coupons for test are created using resin pool

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates generally to the field of testing for failure criteria determination in composite matrices and more particularly to a protocol including a method for coupon fabrication and testing to determine failure characteristics in multi-ply composite systems with templates for distortion comparison and disposition. 
         [0003]    2. Description of the Related Art 
         [0004]    Composite fabrication aircraft and helicopter structural systems requires high reliability for safety of flight elements. Testing for various voids or distortions in the plies of composite materials such as glass reinforced fiber composites and related determinations of engineering quality dispositions for anomalies that are located requires repeatable techniques for development of a database for use in such review. As an example, fiber distortions occur in helicopter rotor blade spar straps near critical root end stations. This area is critical because it is a force concentration area during the operation of the rotor blade. Any degradation of strength in that area is of concern. 
         [0005]    The fiber distortion anomalies are detectable through various testing techniques such as X-ray. However, since no repair is possible upon detection of distorted fibers in the root end as in many other critical structural components in aircraft and helicopters, the disposition can only be “use as is” or “scrap” depending on the severity of the distorted fibered composite. In the specific example this is particularly true if it occurs in the critical blade root end. Current procedures have allowed a number of the blades to be dispositioned “use as is” following careful case-by-case evaluation. 
         [0006]    Current fatigue and crack propagation models and statistical analysis methods employed in analyzing composite anomalies use the Miners Rule or the later fatigue model by Bimbaum-Saunders. Both are models for crack propagation in metal. No current models for glass reinforced composite materials are available. Some limited experimentation has been performed at the University of Akron, Cambridge University and numerous papers are available on the development of finite element models, for example Pratt, W. F. and Allen, M. S.  Patterned Fiber Composites, Inc. Characterization and finite element model correlation of wavy composites ; Caiazzo, A. and Orlet, M., McShane, H., Strait, L., and Rachau, C.  The effects of marcel defects on composite structural properties . Little has been done in the development of empirical data for the determination of the shape of the failure curve for glass reinforced composite with marceled conditions. 
         [0007]    It is therefore desirable to provide consistent and repeatable data for characterization of marceled conditions and their impact on the life of rotor blades and other crack-prone parts made from the same or similar material. Such information is desirable to catalog the physical properties for use in engineering disposition of comparable anomalies identified in production components and to validate the current inspection routines in the composite shop and also to calculate the risk to fielded rotorcraft and/or determine the impact on the manufacturing processes creating rotor blade root ends. 
       SUMMARY OF THE INVENTION 
       [0008]    The embodiments disclosed herein for the present invention provide a coupon fabrication technique with defined distortion in the form of marceled fibers and test protocol to determine the shape of the failure probability density curve to improve the analyses of the risk of fiber distortion anomalies in composite structures. This protocol provides a method to determine the probability of and the severity of the various distorted fiber conditions that might exist on the rotor blades for the exemplary application in the future and those that are currently in fabrication and in service. 
         [0009]    The response variable data and analyses information provided by the invention enables operations and quality personnel to make better informed decisions during production operations and at inspection points during the production and at final buy off of composite structural components using comparative standards derived from the distortion shapes employed in the coupon testing protocol. 
         [0010]    The determination of the failure characteristics instigated by distorted fibers in the material also enables improvements to the design of future composite structures. The data provided by the invention and associated finite element analyses which can be conducted based on the test protocol enhances engineering decision-making ability and add to the knowledge of composite materials engineering, stress engineering, quality engineering and composite testing and quality verifications. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    These and other features and advantages of the present invention will be better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
           [0012]      FIG. 1   a  is side view of a test coupon defined according to the protocol of the present invention; 
           [0013]      FIG. 1   b  is a front view of the test coupon of  FIG. 1   a;    
           [0014]      FIG. 1   c  is a front view of an exemplary test coupon with added gripping pads; 
           [0015]      FIG. 1   d  is a side view of an exemplary test coupon with the added gripping pads. 
           [0016]      FIG. 2  shows distortion curve shapes defined for selecting a test set according to the protocol of the invention and comparative standard templates for uncontoured regions; 
           [0017]      FIG. 3  is a pictorial view of a resin pool distortion shape, as machined, during insertion into the layup; 
           [0018]      FIGS. 4   a - 4   i  show comparative standard templates for determination of distortion sizing; 
           [0019]      FIG. 5  shows comparative standard templates for pin regions with positive curvature; and, 
           [0020]      FIG. 6  shows comparative standard templates for pin regions with negative curvature. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    The protocol of the present invention defines the impact of fiber distortion defects on the tensile strength property of composite lay-ups. A coupon  100 , shown in  FIG. 1   c  employs the same materials and simulates the wave-like characteristics found in marceled distortions present in production fiber composite layups. For an exemplary composite system of BMS 08-196 Unidirectional coupons are built using a multi-ply layup incorporating a resign pool distortion shape selected from a distortion curve set as will be described in greater detail subsequently. For example coupons described herein the layup comprises 40 layers. The coupons are then sliced perpendicular to the layup with a thickness of approximately 0.050 inch. Tapes of varying width are created depending on the number of layers with 1.5 inch to 2.0 inch tapes  102 , shown in  FIGS. 1   a  (exaggerated in the thickness dimension in the figure for clarity) and  1   b  showing a 0.050 slice of the test element resin pool distortion shape  104  included at a predetermined position as described above. The cure cycle replicates the production cure for the material being tested. Gripping pads  106  are added at the top and bottom of the coupon for engagement in a tensile testing machine. 
         [0022]    To replicate potential defect locations, sample coupons are prepared with the defect present in the surface layer, two layers from the surface and at the middle of the layers in the coupon. For the exemplary coupons discussed herein a 40 ply layup is employed. 
         [0023]      FIG. 2  shows exemplary curves  1  to  60  representative of half shapes for idealized cases of the marceled distortions found in composites studied. Curves  1 - 10  have a height of 0.0625 inch with total length (cord) varying from 0.188 inch to 1.5 inches. Similarly, curves  11 - 20  have a height of 0.125 inch with cord varying from 0.188 to 1.5 inches. Curves  21 - 30  have a height of 0.1875, curves  31 - 40  a height of 0.25 inch, curves  41 - 50  a height of 0.3125, curves  51 - 60  a height of 0.375 inch, curves  61 - 70  a height of 0.5 inch. Selected ones of the curves, as will be defined subsequently, have distortion shapes machined from resin pools comprised of the same resin as the composite under test. 
         [0024]    As shown in  FIG. 3 , a resin pool is cured and machined to provide a distortion shape  104  which is inserted between composite layup layers  108  at the location predetermined as previously described. The middle layer location is shown in  FIG. 3  as exemplary. Slicing of the layup to create the test coupons is accomplished as represented by line  1   a - 1   a.    
         [0025]    A distortion category is created by establishing a figure of merit based on the amplitude of the distortion and its length. For the exemplary embodiment, the figure of merit is proportional to h 2  and L and is specifically defined by first determining the aspect ratio, h/L, based on the distortion amplitude and length for each of the shapes defined in  FIG. 2 . A determination of a figure of merit is then accomplished by multiplying the distortion amplitude by the aspect ratio multiplied by a percentage of fiber involvement. This function for the embodiment disclosed herein is equal to the percentage for lugs with less than 80% distortion and grows to 160% for completely involved lugs. A defined distortion category is then determined based on the figure of merit by value assignment where if the figure of merit (FOM) is less than or equal to 0.125 then the distortion category is defined as 1. If 0.125&lt;FOM&lt;=0.25 the distortion category is defined as 1.5. If 0.25&lt;FOM&lt;=0.85 the distortion category is defined as 2. If 0.85&lt;FOM&lt;=1.75 the distortion category is defined as 2.5. If 1.75&lt;FOM&lt;=3.1 the distortion category is defined as 3. If 3.1&lt;FOM&lt;=4.8 the distortion category is defined as 3.5. If 4.8&lt;FOM&lt;=6.8 the distortion category is defined as 4. If 6.8&lt;FOM&lt;=9.3 the distortion category is 4.5. While if the FOM&gt;9.3 the distortion category is defined as 5. Table 1 shows the resulting aspect ratio and calculated FOM for the distortion shapes of  FIG. 2 . Table 2 provides the resulting distortion category with values over 5 being ignored. 
         [0000]    
       
         
               
               
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                 % 
                 % 
                 % 
                 % 
                 % 
                 % 
                 % 
                 % 
                 % 
                 % 
                   
               
               
                 h 
                 L 
                 0.100 
                 0.200 
                 0.300 
                 0.400 
                 0.500 
                 0.600 
                 0.700 
                 0.800 
                 1.100 
                 1.600 
                 h/L 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 0.063 
                 0.188 
                 0.208 
                 0.417 
                 0.625 
                 0.833 
                 1.042 
                 1.250 
                 1.458 
                 1.667 
                 2.292 
                 3.333 
                 3.0 
               
               
                 0.063 
                 0.25 
                 0.156 
                 0.313 
                 0.469 
                 0.625 
                 0.781 
                 0.938 
                 1.094 
                 1.250 
                 1.719 
                 2.500 
                 4.0 
               
               
                 0.063 
                 0.375 
                 0.104 
                 0.208 
                 0.313 
                 0.417 
                 0.521 
                 0.625 
                 0.729 
                 0.833 
                 1.146 
                 1.667 
                 6.0 
               
               
                 0.063 
                 0.5 
                 0.078 
                 0.156 
                 0.234 
                 0.313 
                 0.391 
                 0.469 
                 0.547 
                 0.625 
                 0.859 
                 1.250 
                 8.0 
               
               
                 0.063 
                 0.625 
                 0.063 
                 0.125 
                 0.188 
                 0.250 
                 0.313 
                 0.375 
                 0.438 
                 0.500 
                 0.688 
                 1.000 
                 10.0 
               
               
                 0.063 
                 0.75 
                 0.052 
                 0.104 
                 0.156 
                 0.208 
                 0.260 
                 0.313 
                 0.365 
                 0.417 
                 0.573 
                 0.833 
                 12.0 
               
               
                 0.063 
                 0.875 
                 0.045 
                 0.089 
                 0.134 
                 0.179 
                 0.223 
                 0.268 
                 0.313 
                 0.357 
                 0.491 
                 0.714 
                 14.0 
               
               
                 0.063 
                 1 
                 0.039 
                 0.078 
                 0.117 
                 0.156 
                 0.195 
                 0.234 
                 0.273 
                 0.313 
                 0.430 
                 0.625 
                 16.0 
               
               
                 0.063 
                 1.25 
                 0.031 
                 0.063 
                 0.094 
                 0.125 
                 0.156 
                 0.188 
                 0.219 
                 0.250 
                 0.344 
                 0.500 
                 20.0 
               
               
                 0.063 
                 1.5 
                 0.026 
                 0.052 
                 0.078 
                 0.104 
                 0.130 
                 0.156 
                 0.182 
                 0.208 
                 0.286 
                 0.417 
                 24.0 
               
               
                 0.125 
                 0.188 
                 0.833 
                 1.667 
                 2.500 
                 3.333 
                 4.167 
                 5.000 
                 5.833 
                 6.667 
                 9.167 
                 13.333 
                 1.5 
               
               
                 0.125 
                 0.25 
                 0.625 
                 1.250 
                 1.875 
                 2.500 
                 3.125 
                 3.750 
                 4.375 
                 5.000 
                 6.875 
                 10.000 
                 2.0 
               
               
                 0.125 
                 0.375 
                 0.417 
                 0.833 
                 1.250 
                 1.667 
                 2.083 
                 2.500 
                 2.917 
                 3.333 
                 4.583 
                 6.667 
                 3.0 
               
               
                 0.125 
                 0.5 
                 0.313 
                 0.625 
                 0.938 
                 1.250 
                 1.563 
                 1.875 
                 2.188 
                 2.500 
                 3.438 
                 5.000 
                 4.0 
               
               
                 0.125 
                 0.625 
                 0.250 
                 0.500 
                 0.750 
                 1.000 
                 1.250 
                 1.500 
                 1.750 
                 2.000 
                 2.750 
                 4.000 
                 5.0 
               
               
                 0.125 
                 0.75 
                 0.208 
                 0.417 
                 0.625 
                 0.833 
                 1.042 
                 1.250 
                 1.458 
                 1.667 
                 2.292 
                 3.333 
                 6.0 
               
               
                 0.125 
                 0.875 
                 0.179 
                 0.357 
                 0.536 
                 0.714 
                 0.893 
                 1.071 
                 1.250 
                 1.429 
                 1.964 
                 2.857 
                 7.0 
               
               
                 0.125 
                 1 
                 0.156 
                 0.313 
                 0.469 
                 0.625 
                 0.781 
                 0.938 
                 1.094 
                 1.250 
                 1.719 
                 2.500 
                 8.0 
               
               
                 0.125 
                 1.25 
                 0.125 
                 0.250 
                 0.375 
                 0.500 
                 0.625 
                 0.750 
                 0.875 
                 1.000 
                 1.375 
                 2.000 
                 10.0 
               
               
                 0.125 
                 1.5 
                 0.104 
                 0.208 
                 0.313 
                 0.417 
                 0.521 
                 0.625 
                 0.729 
                 0.833 
                 1.146 
                 1.667 
                 12.0 
               
               
                 0.188 
                 0.188 
                 1.875 
                 3.750 
                 5.625 
                 7.500 
                 9.375 
                 11.250 
                 13.125 
                 15.000 
                 20.625 
                 30.000 
                 1.0 
               
               
                 0.188 
                 0.25 
                 1.406 
                 2.813 
                 4.219 
                 5.625 
                 7.031 
                 8.438 
                 9.844 
                 11.250 
                 15.469 
                 22.500 
                 1.3 
               
               
                 0.188 
                 0.375 
                 0.938 
                 1.875 
                 2.813 
                 3.750 
                 4.688 
                 5.625 
                 6.563 
                 7.500 
                 10.313 
                 15.000 
                 2.0 
               
               
                 0.188 
                 0.5 
                 0.703 
                 1.406 
                 2.109 
                 2.813 
                 3.516 
                 4.219 
                 4.922 
                 5.625 
                 7.734 
                 11.250 
                 2.7 
               
               
                 0.188 
                 0.625 
                 0.563 
                 1.125 
                 1.688 
                 2.250 
                 2.813 
                 3.375 
                 3.938 
                 4.500 
                 6.188 
                 9.000 
                 3.3 
               
               
                 0.188 
                 0.75 
                 0.469 
                 0.938 
                 1.406 
                 1.875 
                 2.344 
                 2.813 
                 3.281 
                 3.750 
                 5.156 
                 7.500 
                 4.0 
               
               
                 0.188 
                 0.875 
                 0.402 
                 0.804 
                 1.205 
                 1.607 
                 2.009 
                 2.411 
                 2.813 
                 3.214 
                 4.420 
                 6.429 
                 4.7 
               
               
                 0.188 
                 1 
                 0.352 
                 0.703 
                 1.055 
                 1.406 
                 1.758 
                 2.109 
                 2.461 
                 2.813 
                 3.867 
                 5.625 
                 5.3 
               
               
                 0.188 
                 1.25 
                 0.281 
                 0.563 
                 0.844 
                 1.125 
                 1.406 
                 1.688 
                 1.969 
                 2.250 
                 3.094 
                 4.500 
                 6.7 
               
               
                 0.188 
                 1.5 
                 0.234 
                 0.469 
                 0.703 
                 0.938 
                 1.172 
                 1.406 
                 1.641 
                 1.875 
                 2.578 
                 3.750 
                 8.0 
               
               
                 0.25 
                 0.1875 
                 3.333 
                 6.667 
                 10.000 
                 13.333 
                 16.667 
                 20.000 
                 23.333 
                 26.667 
                 36.667 
                 53.333 
                 0.8 
               
               
                 0.25 
                 0.25 
                 2.500 
                 5.000 
                 7.500 
                 10.000 
                 12.500 
                 15.000 
                 17.500 
                 20.000 
                 27.500 
                 40.000 
                 1.0 
               
               
                 0.25 
                 0.375 
                 1.667 
                 3.333 
                 5.000 
                 6.667 
                 8.333 
                 10.000 
                 11.667 
                 13.333 
                 18.333 
                 26.667 
                 1.5 
               
               
                 0.25 
                 0.5 
                 1.250 
                 2.500 
                 3.750 
                 5.000 
                 6.250 
                 7.500 
                 8.750 
                 10.000 
                 13.750 
                 20.000 
                 2.0 
               
               
                 0.25 
                 0.625 
                 1.000 
                 2.000 
                 3.000 
                 4.000 
                 5.000 
                 6.000 
                 7.000 
                 8.000 
                 11.000 
                 16.000 
                 2.5 
               
               
                 0.25 
                 0.75 
                 0.833 
                 1.667 
                 2.500 
                 3.333 
                 4.167 
                 5.000 
                 5.833 
                 6.667 
                 9.167 
                 13.333 
                 3.0 
               
               
                 0.25 
                 0.875 
                 0.714 
                 1.429 
                 2.143 
                 2.857 
                 3.571 
                 4.286 
                 5.000 
                 5.714 
                 7.857 
                 11.429 
                 3.5 
               
               
                 0.25 
                 1 
                 0.625 
                 1.250 
                 1.875 
                 2.500 
                 3.125 
                 3.750 
                 4.375 
                 5.000 
                 6.875 
                 10.000 
                 4.0 
               
               
                 0.25 
                 1.25 
                 0.500 
                 1.000 
                 1.500 
                 2.000 
                 2.500 
                 3.000 
                 3.500 
                 4.000 
                 5.500 
                 8.000 
                 5.0 
               
               
                 0.25 
                 1.5 
                 0.417 
                 0.833 
                 1.250 
                 1.667 
                 2.083 
                 2.500 
                 2.917 
                 3.333 
                 4.583 
                 6.667 
                 6.0 
               
               
                 0.3125 
                 0.1875 
                 5.208 
                 10.417 
                 15.625 
                 20.833 
                 26.042 
                 31.250 
                 36.458 
                 41.667 
                 57.292 
                 83.333 
                 0.6 
               
               
                 0.3125 
                 0.25 
                 3.906 
                 7.813 
                 11.719 
                 15.625 
                 19.531 
                 23.438 
                 27.344 
                 31.250 
                 42.969 
                 62.500 
                 0.8 
               
               
                 0.3125 
                 0.375 
                 2.604 
                 5.208 
                 7.813 
                 10.417 
                 13.021 
                 15.625 
                 18.229 
                 20.833 
                 28.646 
                 41.667 
                 1.2 
               
               
                 0.3125 
                 0.5 
                 1.953 
                 3.906 
                 5.859 
                 7.813 
                 9.766 
                 11.719 
                 13.672 
                 15.625 
                 21.484 
                 31.250 
                 1.6 
               
               
                 0.3125 
                 0.625 
                 1.563 
                 3.125 
                 4.688 
                 6.250 
                 7.813 
                 9.375 
                 10.938 
                 12.500 
                 17.188 
                 25.000 
                 2.0 
               
               
                 0.3125 
                 0.75 
                 1.302 
                 2.604 
                 3.906 
                 5.208 
                 6.510 
                 7.813 
                 9.115 
                 10.417 
                 14.323 
                 20.833 
                 2.4 
               
               
                 0.3125 
                 0.875 
                 1.116 
                 2.232 
                 3.348 
                 4.464 
                 5.580 
                 6.696 
                 7.813 
                 8.929 
                 12.277 
                 17.857 
                 2.8 
               
               
                 0.3125 
                 1 
                 0.977 
                 1.953 
                 2.930 
                 3.906 
                 4.883 
                 5.859 
                 6.836 
                 7.813 
                 10.742 
                 15.625 
                 3.2 
               
               
                 0.3125 
                 1.25 
                 0.781 
                 1.563 
                 2.344 
                 3.125 
                 3.906 
                 4.688 
                 5.469 
                 6.250 
                 8.594 
                 12.500 
                 4.0 
               
               
                 0.3125 
                 1.5 
                 0.651 
                 1.302 
                 1.953 
                 2.604 
                 3.255 
                 3.906 
                 4.557 
                 5.208 
                 7.161 
                 10.417 
                 4.8 
               
               
                 0.375 
                 0.1875 
                 7.500 
                 15.000 
                 22.500 
                 30.000 
                 37.500 
                 45.000 
                 52.500 
                 60.000 
                 82.500 
                 120.000 
                 0.5 
               
               
                 0.375 
                 0.25 
                 5.625 
                 11.250 
                 16.875 
                 22.500 
                 28.125 
                 33.750 
                 39.375 
                 45.000 
                 61.875 
                 90.000 
                 0.7 
               
               
                 0.375 
                 0.375 
                 3.750 
                 7.500 
                 11.250 
                 15.000 
                 18.750 
                 22.500 
                 26.250 
                 30.000 
                 41.250 
                 60.000 
                 1.0 
               
               
                 0.375 
                 0.5 
                 2.813 
                 5.625 
                 8.438 
                 11.250 
                 14.063 
                 16.875 
                 19.688 
                 22.500 
                 30.938 
                 45.000 
                 1.3 
               
               
                 0.375 
                 0.625 
                 2.250 
                 4.500 
                 6.750 
                 9.000 
                 11.250 
                 13.500 
                 15.750 
                 18.000 
                 24.750 
                 36.000 
                 1.7 
               
               
                 0.375 
                 0.75 
                 1.875 
                 3.750 
                 5.625 
                 7.500 
                 9.375 
                 11.250 
                 13.125 
                 15.000 
                 20.625 
                 30.000 
                 2.0 
               
               
                 0.375 
                 0.875 
                 1.607 
                 3.214 
                 4.821 
                 6.429 
                 8.036 
                 9.643 
                 11.250 
                 12.857 
                 17.679 
                 25.714 
                 2.3 
               
               
                 0.375 
                 1 
                 1.406 
                 2.813 
                 4.219 
                 5.625 
                 7.031 
                 8.438 
                 9.844 
                 11.250 
                 15.469 
                 22.500 
                 2.7 
               
               
                 0.375 
                 1.25 
                 1.125 
                 2.250 
                 3.375 
                 4.500 
                 5.625 
                 6.750 
                 7.875 
                 9.000 
                 12.375 
                 18.000 
                 3.3 
               
               
                 0.375 
                 1.5 
                 0.938 
                 1.875 
                 2.813 
                 3.750 
                 4.688 
                 5.625 
                 6.563 
                 7.500 
                 10.313 
                 15.000 
                 4.0 
               
               
                 0.5 
                 0.1875 
                 13.333 
                 26.667 
                 40.000 
                 53.333 
                 66.667 
                 80.000 
                 93.333 
                 106.667 
                 146.667 
                 213.333 
                 0.4 
               
               
                 0.5 
                 0.25 
                 10.000 
                 20.000 
                 30.000 
                 40.000 
                 50.000 
                 60.000 
                 70.000 
                 80.000 
                 110.000 
                 160.000 
                 0.5 
               
               
                 0.5 
                 0.375 
                 6.667 
                 13.333 
                 20.000 
                 26.667 
                 33.333 
                 40.000 
                 46.667 
                 53.333 
                 73.333 
                 106.667 
                 0.8 
               
               
                 0.5 
                 0.5 
                 5.000 
                 10.000 
                 15.000 
                 20.000 
                 25.000 
                 30.000 
                 35.000 
                 40.000 
                 55.000 
                 80.000 
                 1.0 
               
               
                 0.5 
                 0.625 
                 4.000 
                 8.000 
                 12.000 
                 16.000 
                 20.000 
                 24.000 
                 28.000 
                 32.000 
                 44.000 
                 64.000 
                 1.3 
               
               
                 0.5 
                 0.75 
                 3.333 
                 6.667 
                 10.000 
                 13.333 
                 16.667 
                 20.000 
                 23.333 
                 26.667 
                 36.667 
                 53.333 
                 1.5 
               
               
                 0.5 
                 0.875 
                 2.857 
                 5.714 
                 8.571 
                 11.429 
                 14.286 
                 17.143 
                 20.000 
                 22.857 
                 31.429 
                 45.714 
                 1.8 
               
               
                 0.5 
                 1 
                 2.500 
                 5.000 
                 7.500 
                 10.000 
                 12.500 
                 15.000 
                 17.500 
                 20.000 
                 27.500 
                 40.000 
                 2.0 
               
               
                 0.5 
                 1.25 
                 2.000 
                 4.000 
                 6.000 
                 8.000 
                 10.000 
                 12.000 
                 14.000 
                 16.000 
                 22.000 
                 32.000 
                 2.5 
               
               
                 0.5 
                 1.5 
                 1.667 
                 3.333 
                 5.000 
                 6.667 
                 8.333 
                 10.000 
                 11.667 
                 13.333 
                 18.333 
                 26.667 
                 3.0 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                   
                   
                 % 
                 % 
                 % 
                 % 
                 % 
                 % 
                 % 
                 % 
                 % 
                 % 
               
               
                   
                 h 
                 L 
                 10% 
                 20% 
                 30% 
                 40% 
                 50% 
                 60% 
                 70% 
                 80% 
                 90% 
                 100% 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 1 
                 0.063 
                 0.188 
                 1.5 
                 2.0 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 3.0 
                 3.5 
               
               
                 2 
                 0.063 
                 0.25 
                 1.5 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 3.0 
               
               
                 3 
                 0.063 
                 0.375 
                 1.0 
                 1.5 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
               
               
                 4 
                 0.063 
                 0.5 
                 1.0 
                 1.5 
                 1.5 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
               
               
                 5 
                 0.063 
                 0.625 
                 1.0 
                 1.5 
                 1.5 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.5 
               
               
                 6 
                 0.063 
                 0.75 
                 1.0 
                 1.0 
                 1.5 
                 1.5 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
               
               
                 7 
                 0.063 
                 0.875 
                 1.0 
                 1.0 
                 1.5 
                 1.5 
                 1.5 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
               
               
                 8 
                 0.063 
                 1 
                 1.0 
                 1.0 
                 1.0 
                 1.5 
                 1.5 
                 1.5 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
               
               
                 9 
                 0.063 
                 1.25 
                 1.0 
                 1.0 
                 1.0 
                 1.5 
                 1.5 
                 1.5 
                 1.5 
                 2.0 
                 2.0 
                 2.0 
               
               
                 10 
                 0.063 
                 1.5 
                 1.0 
                 1.0 
                 1.0 
                 1.0 
                 1.5 
                 1.5 
                 1.5 
                 1.5 
                 2.0 
                 2.0 
               
               
                 11 
                 0.125 
                 0.188 
                 2.0 
                 2.5 
                 3.0 
                 3.5 
                 3.5 
                 4.0 
                 4.0 
                 4.0 
                 4.5 
                 5.0 
               
               
                 12 
                 0.125 
                 0.25 
                 2.0 
                 2.5 
                 3.0 
                 3.0 
                 3.5 
                 3.5 
                 3.5 
                 4.0 
                 4.5 
                 5.0 
               
               
                 13 
                 0.125 
                 0.375 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
                 3.0 
                 3.0 
                 3.0 
                 3.5 
                 3.5 
                 4.0 
               
               
                 14 
                 0.125 
                 0.5 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
                 2.5 
                 3.0 
                 3.0 
                 3.0 
                 3.5 
                 4.0 
               
               
                 15 
                 0.125 
                 0.625 
                 2.0 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
                 2.5 
                 3.0 
                 3.0 
                 3.0 
                 3.5 
               
               
                 16 
                 0.125 
                 0.75 
                 1.5 
                 2.0 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 3.0 
                 3.5 
               
               
                 17 
                 0.125 
                 0.875 
                 1.5 
                 2.0 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 3.0 
                 3.0 
               
               
                 18 
                 0.125 
                 1 
                 1.5 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 3.0 
               
               
                 19 
                 0.125 
                 1.25 
                 1.5 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
                 2.5 
                 3.0 
               
               
                 20 
                 0.125 
                 1.5 
                 1.0 
                 1.5 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
               
               
                 21 
                 0.188 
                 0.188 
                 3.0 
                 3.5 
                 4.0 
                 4.5 
                 5.0 
                 5.0 
               
               
                 22 
                 0.188 
                 0.25 
                 2.5 
                 3.0 
                 3.5 
                 4.0 
                 4.5 
                 4.5 
                 5.0 
                 5.0 
               
               
                 23 
                 0.188 
                 0.375 
                 2.5 
                 3.0 
                 3.0 
                 3.5 
                 3.5 
                 4.0 
                 4.0 
                 4.5 
                 5.0 
                 5.0 
               
               
                 24 
                 0.188 
                 0.5 
                 2.0 
                 2.5 
                 3.0 
                 3.0 
                 3.5 
                 3.5 
                 4.0 
                 4.0 
                 4.5 
                 5.0 
               
               
                 25 
                 0.188 
                 0.625 
                 2.0 
                 2.5 
                 2.5 
                 3.0 
                 3.0 
                 3.5 
                 3.5 
                 3.5 
                 4.0 
                 4.5 
               
               
                 26 
                 0.188 
                 0.75 
                 2.0 
                 2.5 
                 2.5 
                 3.0 
                 3.0 
                 3.0 
                 3.5 
                 3.5 
                 4.0 
                 4.5 
               
               
                 27 
                 0.188 
                 0.875 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
                 3.0 
                 3.0 
                 3.0 
                 3.5 
                 3.5 
                 4.0 
               
               
                 28 
                 0.188 
                 1 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
                 3.0 
                 3.0 
                 3.0 
                 3.0 
                 3.5 
                 4.0 
               
               
                 29 
                 0.188 
                 1.25 
                 2.0 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
                 2.5 
                 3.0 
                 3.0 
                 3.0 
                 3.5 
               
               
                 30 
                 0.188 
                 1.5 
                 1.5 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 3.0 
                 3.0 
                 3.5 
               
               
                 31 
                 0.25 
                 0.188 
                 3.5 
                 4.0 
                 5.0 
                 5.0 
               
               
                 32 
                 0.25 
                 0.25 
                 3.0 
                 4.0 
                 4.5 
                 5.0 
                 5.0 
               
               
                 33 
                 0.25 
                 0.375 
                 2.5 
                 3.5 
                 4.0 
                 4.0 
                 4.5 
                 5.0 
                 5.0 
               
               
                 34 
                 0.25 
                 0.5 
                 2.5 
                 3.0 
                 3.5 
                 4.0 
                 4.0 
                 4.5 
                 4.5 
                 5.0 
                 5.0 
               
               
                 35 
                 0.25 
                 0.625 
                 2.5 
                 3.0 
                 3.0 
                 3.5 
                 4.0 
                 4.0 
                 4.5 
                 4.5 
                 5.0 
                 5.0 
               
               
                 36 
                 0.25 
                 0.75 
                 2.0 
                 2.5 
                 3.0 
                 3.5 
                 3.5 
                 4.0 
                 4.0 
                 4.0 
                 4.5 
                 5.0 
               
               
                 37 
                 0.25 
                 0.875 
                 2.0 
                 2.5 
                 3.0 
                 3.0 
                 3.5 
                 3.5 
                 4.0 
                 4.0 
                 4.5 
                 5.0 
               
               
                 38 
                 0.25 
                 1 
                 2.0 
                 2.5 
                 3.0 
                 3.0 
                 3.5 
                 3.5 
                 3.5 
                 4.0 
                 4.5 
                 5.0 
               
               
                 39 
                 0.25 
                 1.25 
                 2.0 
                 2.5 
                 2.5 
                 3.0 
                 3.0 
                 3.0 
                 3.5 
                 3.5 
                 4.0 
                 4.5 
               
               
                 40 
                 0.25 
                 1.5 
                 2.0 
                 2.0 
                 2.5 
                 2.5 
                 3.0 
                 3.0 
                 3.0 
                 3.5 
                 3.5 
                 4.0 
               
               
                 41 
                 0.313 
                 0.188 
                 4.0 
                 5.0 
               
               
                 42 
                 0.313 
                 0.25 
                 3.5 
                 4.5 
                 5.0 
                 5.0 
               
               
                 43 
                 0.313 
                 0.375 
                 3.0 
                 4.0 
                 4.5 
                 5.0 
                 5.0 
               
               
                 44 
                 0.313 
                 0.5 
                 3.0 
                 3.5 
                 4.0 
                 4.5 
                 5.0 
                 5.0 
               
               
                 45 
                 0.313 
                 0.625 
                 2.5 
                 3.5 
                 3.5 
                 4.0 
                 4.5 
                 5.0 
                 5.0 
               
               
                 46 
                 0.313 
                 0.75 
                 2.5 
                 3.0 
                 3.5 
                 4.0 
                 4.0 
                 4.5 
                 4.5 
                 5.0 
                 5.0 
               
               
                 47 
                 0.313 
                 0.875 
                 2.5 
                 3.0 
                 3.5 
                 3.5 
                 4.0 
                 4.0 
                 4.5 
                 4.5 
                 5.0 
                 5.0 
               
               
                 48 
                 0.313 
                 1 
                 2.5 
                 3.0 
                 3.0 
                 3.5 
                 4.0 
                 4.0 
                 4.5 
                 4.5 
                 5.0 
                 5.0 
               
               
                 49 
                 0.313 
                 1.25 
                 2.0 
                 2.5 
                 3.0 
                 3.5 
                 3.5 
                 3.5 
                 4.0 
                 4.0 
                 4.5 
                 5.0 
               
               
                 50 
                 0.313 
                 1.5 
                 2.0 
                 2.5 
                 3.0 
                 3.0 
                 3.5 
                 3.5 
                 3.5 
                 4.0 
                 4.5 
                 5.0 
               
               
                 51 
                 0.375 
                 0.188 
                 4.5 
                 5.0 
               
               
                 52 
                 0.375 
                 0.25 
                 4.0 
                 5.0 
                 5.0 
               
               
                 53 
                 0.375 
                 0.375 
                 3.5 
                 4.5 
                 5.0 
                 5.0 
               
               
                 54 
                 0.375 
                 0.5 
                 3.0 
                 4.0 
                 4.5 
                 5.0 
                 5.0 
               
               
                 55 
                 0.375 
                 0.625 
                 3.0 
                 3.5 
                 4.0 
                 4.5 
                 5.0 
                 5.0 
               
               
                 56 
                 0.375 
                 0.75 
                 3.0 
                 3.5 
                 4.0 
                 4.5 
                 5.0 
                 5.0 
               
               
                 57 
                 0.375 
                 0.875 
                 2.5 
                 3.5 
                 4.0 
                 4.0 
                 4.5 
                 5.0 
                 5.0 
               
               
                 58 
                 0.375 
                 1 
                 2.5 
                 3.0 
                 3.5 
                 4.0 
                 4.5 
                 4.5 
                 5.0 
                 5.0 
               
               
                 59 
                 0.375 
                 1.25 
                 2.5 
                 3.0 
                 3.5 
                 3.5 
                 4.0 
                 4.0 
                 4.5 
                 4.5 
                 5.0 
                 5.0 
               
               
                 60 
                 0.375 
                 1.5 
                 2.5 
                 3.0 
                 3.0 
                 3.5 
                 3.5 
                 4.0 
                 4.0 
                 4.5 
                 5.0 
                 5.0 
               
               
                 61 
                 0.500 
                 0.188 
                 5.0 
               
               
                 62 
                 0.500 
                 0.25 
                 5.0 
               
               
                 63 
                 0.500 
                 0.375 
                 4.0 
                 5.0 
               
               
                 64 
                 0.500 
                 0.5 
                 4.0 
                 5.0 
               
               
                 65 
                 0.500 
                 0.625 
                 3.5 
                 4.5 
                 5.0 
               
               
                 66 
                 0.500 
                 0.75 
                 3.5 
                 4.0 
                 5.0 
                 5.0 
               
               
                 67 
                 0.500 
                 0.875 
                 3.0 
                 4.0 
                 4.5 
                 5.0 
                 5.0 
               
               
                 68 
                 0.500 
                 1 
                 3.0 
                 4.0 
                 4.5 
                 5.0 
                 5.0 
               
               
                 69 
                 0.500 
                 1.25 
                 3.0 
                 3.5 
                 4.0 
                 4.5 
                 5.0 
                 5.0 
               
               
                 70 
                 0.500 
                 1.5 
                 2.5 
                 3.5 
                 4.0 
                 4.0 
                 4.5 
                 5.0 
                 5.0 
               
               
                   
               
             
          
         
       
     
         [0026]    The testing protocol provides for the preparation of coupons as described previously with 2 category  2  curves, 2 category  3  and 2 category  4  to simulate the changes in both amplitude and wavelength that categorize a typical fiber distortion wave as a 2, 3, or 4. The shape factor and the amplitude are controlled by the inserts that created by selecting a curve from the inspection standard that is a score of 2, 3, or 4. One that has a high (tall) amplitude and one that has a low (short) amplitude. These 6 inserts provide the standard shapes for the resin pocket around which the fiber distortion is created. The location of the insert will either be at the edge, 2 plies in, or at the middle of the coupon, 20 plies in. 
         [0027]    The resulting test design is shown in Table 3 
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                   
                   
                   
                 Wave 
                   
               
               
                 StdOrder 
                 RunOrder 
                 Amplitude 
                 Shape 
                 location 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 17 
                 1 
                 short 
                 3 
                 edge 
               
               
                 14 
                 2 
                 short 
                 1 
                 middle 
               
               
                 3 
                 3 
                 short 
                 2 
                 edge 
               
               
                 18 
                 4 
                 short 
                 3 
                 middle 
               
               
                 12 
                 5 
                 tall 
                 3 
                 middle 
               
               
                 22 
                 6 
                 tall 
                 2 
                 middle 
               
               
                 34 
                 7 
                 tall 
                 2 
                 middle 
               
               
                 13 
                 8 
                 short 
                 1 
                 edge 
               
               
                 9 
                 9 
                 tall 
                 2 
                 edge 
               
               
                 35 
                 10 
                 tall 
                 3 
                 edge 
               
               
                 6 
                 11 
                 short 
                 3 
                 middle 
               
               
                 19 
                 12 
                 tall 
                 1 
                 edge 
               
               
                 26 
                 13 
                 short 
                 1 
                 middle 
               
               
                 29 
                 14 
                 short 
                 3 
                 edge 
               
               
                 27 
                 15 
                 short 
                 2 
                 edge 
               
               
                 16 
                 16 
                 short 
                 2 
                 middle 
               
               
                 24 
                 17 
                 tall 
                 3 
                 middle 
               
               
                 15 
                 18 
                 short 
                 2 
                 edge 
               
               
                 30 
                 19 
                 short 
                 3 
                 middle 
               
               
                 36 
                 20 
                 tall 
                 3 
                 middle 
               
               
                 7 
                 21 
                 tall 
                 1 
                 edge 
               
               
                 25 
                 22 
                 short 
                 1 
                 edge 
               
               
                 5 
                 23 
                 short 
                 3 
                 edge 
               
               
                 1 
                 24 
                 short 
                 1 
                 edge 
               
               
                 2 
                 25 
                 short 
                 1 
                 middle 
               
               
                 33 
                 26 
                 tall 
                 2 
                 edge 
               
               
                 23 
                 27 
                 tall 
                 3 
                 edge 
               
               
                 4 
                 28 
                 short 
                 2 
                 middle 
               
               
                 32 
                 29 
                 tall 
                 1 
                 middle 
               
               
                 20 
                 30 
                 tall 
                 1 
                 middle 
               
               
                 31 
                 31 
                 tall 
                 1 
                 edge 
               
               
                 21 
                 32 
                 tall 
                 2 
                 edge 
               
               
                 10 
                 33 
                 tall 
                 2 
                 middle 
               
               
                 11 
                 34 
                 tall 
                 3 
                 edge 
               
               
                 8 
                 35 
                 tall 
                 1 
                 middle 
               
               
                 28 
                 36 
                 short 
                 2 
                 middle 
               
               
                   
               
             
          
         
       
     
         [0028]    The test protocol is repeated as required to determine initial failure using a load line parallel to or normal to the axis of the marcel with a force testing machine at varying head speeds. Repetition of the protocol for varying temperature and moisture or other operationally specific environmental conditions provides additional data to establish acceptance criteria. The stress levels for fatigue testing will vary by material and category of distortion. 
         [0029]    The data provided by the test protocol is then applied to the distortion characteristics defined in Table 2 to provide a definitive means for determining whether the associated defect as characterized by the table has engineering structural properties sufficient for a “use as is” determination or whether the structural properties warrant a “scrap” disposition. 
         [0030]    The curves of  FIG. 2  provide templates for determination of approximate shape of a distortion in a production composite identifiable using the tracer fibers present in the layup. Tracer fibers are doped prior to composite creation to allow visualization of fiber placement and distortion. 
         [0031]    The templates of  FIGS. 4   a - 4   i  are employed in inspection to determine the number of plies affected by a distortion for the composite embodiments defined herein.  FIG. 4   a  provides a boundary for a distortion involving 10 plies or less,  FIG. 4   b  a boundary for a distortion involving 20 plies or less  FIG. 4   c  30 plies or less,  FIG. 4   d  40 plies or less,  FIG. 4   e  50 plies or less,  FIG. 4   f  60 plies or less,  FIG. 4   g  70 plies or less,  FIG. 4   h  80 plies or less and  FIG. 4   i  90 plies or less. 
         [0032]      FIGS. 5 and 6  provide templates for determination of approximate shape of a distortion in a production composite identifiable using the tracer fibers where the distortion is present in a region surrounding a pin in the layup.  FIG. 5  with shapes  1 A- 60 A provide the positive curvature while  FIG. 6  with shapes  1 B- 60 B demonstrate a negative curvature. 
         [0033]    The determined shape and number of plies involved in a distortion are then applied to define the distortion category for determining the appropriate disposition of the defect. 
         [0034]    Having now described the invention in detail as required by the patent statutes, those skilled in the art will recognize modifications and substitutions to the specific embodiments disclosed herein. Such modifications are within the scope and intent of the present invention as defined in the following claims.