bluuebunny/crossref_metadata_2025 huggingface dataset:
The Packing of a Template on a Flat Surface
Authors: Chow W. W.
Published: January 2010

Two ways of nesting are covered: (1) all templates in uniform orientation, and (2) alternate columns of inverted templates. Columns of templates are formed and neighboring columns are meshed together. Then the template is rotated to a new orientation. The optimum packing is obtained by searching through the tightest packing of individual orientations. This method is based on the periodicity of interlocking shapes. The search covers all possible orientations and relationships of one template to another. An interlocking enclosure can be formed around the template by including the gaps. If the enclosure is not detrimental to the design of the template, this new shape is a scrap-free template.
Interaction Curves as a Tool in Optimization and Decision Making
Authors: Siddall J. N. , Michael W. K.
Published: January 2010

This paper explores the use of soft specifications in design optimization by relaxing hard specifications and generating a set of interaction curves. The use of the interaction curves are discussed and applied to two design examples. Classification of interaction curves into two types (A and B) has been defined according to whether or not the objective function surface is a function of the specifications. A convenient way of detecting a global optimum is also described.
Small-Scale Design Optimization Using an Interactive Minicomputer
Authors: Ellis J.
Published: January 2010

This paper offers a new approach to small-scale design optimization which combines the philosophy of R. C. Johnson’s Method of Optimum Design with the use of a relatively simple and concise direct search strategy implemented on a minicomputer. The procedure is illustrated through the solution of a previously published problem involving the maximization of the reflector saving in the design of a reflected spherical core nuclear reactor.
Large Scale Nonlinear Programming Using The Generalized Reduced Gradient Method
Authors: Gabriele G. A. , Ragsdell K. M.
Published: January 2010

An extension of the generalized reduced gradient (GRG) method to large scale nonlinear programs with nonlinear constraints is discussed. The approach presented here represents the adoption of efficient methods for sparse matrices within the framework of the GRG algorithm. The resulting code, LGOPT, is described, and experience with a class of minimum weight structural problems is given.
Impact of the Nonlinear Connection Torque Between Truck and Car-Body on the Transversal Stability of a Railway-Car
Authors: Richard J. , Joly R.
Published: January 2010

Matrix (A) shows the dynamic behavior of a high speed free truck running on an aligned track under optimal geometric conditions. The maximum running speed will be lower than the critical speed inherent to the system which is determined by the first eigenvalue of the matrix for which the real part is small and positive. The increase of this critical speed has been observed by an increase of the connection stiffness between car-body and truck. In fact, the car-body truck connection includes more than the classical connection. It includes hydraulic damping devices whose force-displacement diagram is similar to that of a friction damping device. After considering the elastic deformation of the connecting system ensured by the damping devices between truck and car-body, and the connecting springs between truck and car-body mounted in parallel, we observe a drawback torque relative to the truck. This characteristic can be compared to an hysteresis cycle. The initiation of cycles with partially constant magnitudes and frequencies, while the truck is running, enables the use of the first harmonic method. Therefore, this method is applied, and a complex term is added to the a33 element of the first matrix (A).
“Chatter-Proof” Overhang Boring Bars—Stability Criteria and Design Procedure for a New Type of Damped Boring Bar
Authors: New R. W. , Au Y. H. J.
Published: January 2010

The paper reviews briefly the vibration problems encountered when using overhung boring bars to profile bore high duty alloy workpieces. It shows how the dynamic instability can be successfully represented by a self-induction term and incorporated in the equations of motion for an analogue of a boring bar, but which incorporates new information of the mechanism of operation of a Lanchester damper recently reported [1]. The solutions for maximum performance are given and the method for using these to evolve an optimization design procedure are described. Further new information on absorber performance is given which explains how response curves can be interpreted and, finally, the conditions and performance for machining “difficult” high duty alloys are discussed.
On a Numerical Method for Solution of the Mathieu-Hill Type Equations
Authors: Midha A. , Badlani M. L.
Published: January 2010

This paper presents a computer-programmable numerical method for the solution of a class of linear, second order differential equations with periodic coefficients of the Mathieu-Hill type. The method is applicable only when the initial conditions are prescribed and the solution is not requiried to be periodic. The solution is facilitated by representing the coefficient functions as a sum of step functions over corresponding sub-intervals of the fundamental interval. During each sub-interval, the solution form is assumed to be that of the differential equations with “constant” coefficients. Constraint equations are derived from imposing the conditions of “compatibility” of response at the end nodes of the intermediate sub-intervals. This set of simultaneous linear equations is expressed in matrix form. The matrix of coefficients may be represented as a triangular one. This form greatly simplifies the solution process for simultaneous equations. The method is illustrated by its application to some specific problems.
Axial Fatigue Strength of Carbon Fibre Reinforced Bone Cement
Authors: Martin K. F. , Davies R. T. , Rasiah P. N.
Published: January 2010

The use of surface treated high tensile carbon fibers as reinforcing in acrylic bone cement is discussed. This reinforcement is shown to have certain advantages over untreated high modulus fibers as previously advocated in that much smaller proportions of fiber produce a similar improvement in fatigue life. The use of smaller fiber proportion also has the beneficial side effect of retaining the good viscosity properties of the unreinforced acrylic cement.
Design of Ellipsoidal and Toroidal Pressure Vessels to Probabilistic Criteria
Authors: Smith C. O.
Published: January 2010

Ellipsoids are frequently used for end closure of cylindrical pressure shells. Toroids of elliptic or circular cross-section, are widely used, e.g., for connecting two parallel legs in a U-shape. This paper presents equations for the means and standard deviations of stresses developed in ellipsoids and toroids with internal pressure. Inherent in these equations are the facts that: (a) design variables are generally characterized by spectra of values, rather than by unique values, and (b) a small, but finite, probability of failure must be recognized in any design. By coupling the stresses due to the applied loading as calculated by the equations given in the paper with the strength available in a material, reliability (or the alternative probability of failure) can be calculated. Conversely, for a given reliability the appropriate size can be determined. Appropriate illustrations of application of these equations are provided through tables and figures. The difficulty of relying on a factor of safety is demonstrated.
A Finite Rotating Shaft Element Using Timoshenko Beam Theory
Authors: Nelson H. D.
Published: January 2010

The use of finite elements for simulation of rotor systems has received considerable attention within the last few years. The published works have included the study of the effects of rotatory inertia, gyroscopic moments, axial load, and internal damping; but have not included shear deformation or axial torque effects. This paper generalizes the previous works by utilizing Timoshenko beam theory for establishing the shape functions and, thereby including transverse shear effects. Internal damping is not included but the extension is straight forward. Comparison is made of the finite element analysis with classical dosed form Timoshenko beam theory analysis for nonrotating and rotating shafts.
Loading Conditions in Bolted and Riveted Joints Affected by Plate Thickness Ratio
Authors: Ziada H. H. , Abd El Latif A. K.
Published: January 2010

Bolted and riveted connections are quite commonly encountered in various design problems. Many trials have been carried out recently to determine the stress distribution in bolted and riveted joints which is of extreme importance in the design of such joints. Effect of many parameters has been investigated, however effect of thickness ratio of the joint plates did not take too much attention. In this analytic work the effect of various plate thickness on the load and stress distribution in cylindrical bolted joints has been investigated using the finite element technique. Computed results show that the load as well as the stress or pressure distribution under bolt-head or nut are not constant nor uniform. Whatever the thickness ratio of the two plates (I1/L2), constant load and stress occurred across the joint under the bolt-head end. Maximum stress on surface and up to the mid plane level showed an increase with the thickness ratio. However the maximum stress on interface decreases with the thickness ratio to reach its lowest at L1/L2 = 1. End of loading on surface or at mid plane increases with the increase in thickness ratio, and tends to approach a constant value at L1/L2 equals 10 or more—on interface the opening position—represented by diameter of joint to bolt diameter D/d, reaches a maximum value of 3.5 then decreases rapidly to reach a constant value of about 2.5 for L1/L2 = 10 or more. Also the thickness of the plate (L1) has a pronounced effect on the opening position.
Hydrodynamic Lubrication of Journal Bearings with a Polymer Melt
Authors: Accorsi J. V. , DeRossett T. A.
Published: January 2010

An experimental investigation of hydrodynamic lubrication of journal bearings was conducted using a polymer melt as the lubricating fluid. The test apparatus monitored the pressure profile, eccentricity ratio, axial flow rate and frictional power loss for a bearing with L/D = 1.5. Due to the non-Newtonian viscosity/shear-rate relation of the polymer, it was necessary to define a generalized Sommerfeld number in order to plot the data. The results provide a tool for the design of polymer lubricated bearings.
Roller Chain as a Transfer Drive for the Automobile
Authors: Davies D. N. C. , Gustafsson K. G. , Nordkvist K. E. , Owen P. J.
Published: January 2010

The paper is the result of a joint effort by Renold Ltd. and Saab Scania dealing with the development of a transfer drive system for a production Saab front wheel drive automobile. The drive consists of three simple roller chains staggered third of a tooth combined with automatic chain tensioning and adjustment. The design of the transfer drive is described - comparisons with gears - bearing arrangements - resulting economies etc. Development of the chain system is described together with details of automatic tensioning and load measurement. The Saab development program is dealt with including high-speed rig and road testing plus noise evaluation and assessment. The mass production aspect, quality control, and experience in service is also covered.
Adaption of Continuously Variable Transmissions to the Characteristic of a Driven Machine by Bicoupled Planetary Transmissions
Authors: Mu¨ller H. W.
Published: January 2010

Bicoupled Planetary Transmissions composed of any variable Transmission and a planetary gear can be designed to realize any optional speed ratio range including speed reversal and its output characteristic can be approached to the characteristic of the driven machine in order to obtain an economic overall transmission. The paper describes a standardized method to design and to optimize such transmissions.
Analysis and Design of a Uniform-Clearance, Pumping-Ring Rod Seal for the Stirling Engine
Authors: Etsion I.
Published: January 2010

A uniform-clearance pumping ring, as opposed to the conventional taper-clearance one, is described. The uniform-clearance concept eliminates complex elastohydrodynamic problems and enables a simple analytical treatment to be made. An analytical expression is derived for the pumping rate showing the effect of various design parameters on the pumping ring’s performance. An optimum clearance is found by which the pumping rate is maximized and a numerical example is presented to demonstrate the potential of the uniform-clearance design.
Methods of Synthesis and Analysis for Hypoid Gear-Drives of “Formate” and “Helixform”—Part 2. Machine Setting Calculations for the Pinions of Formate and Helixform Gears
Authors: Litvin F. L. , Gutman Y.
Published: January 2010

The second article part is devoted to the calculation of machine settings for Hypoid gear-drive pinions being generated by “Formate” and “Helixform” cutting methods. The solution is based on a local synthesis method by following assumptions: (1) the member-gear surfaceΣ2 is given (the surface Σ2 becomes known after the determination of its machine settings, see article part 1): (2) the being obtained machine settings for the pinion must guarantee: (a) that the member-gear surface Σ2 will be in contact with the pinion surface Σ1 at a choosen point M, (b) that at M and in the vicinity of M prescribed conditions of meshing will be provided.
Design Nomographs of Compression Helical Springs for Predetermined Reliability Levels
Authors: Thien My Dao , Massoud M.
Published: January 2010

This paper discusses a probabilistic approach for the design of Compression Closely Coiled Helical Springs subjected to periodic axial loading. The classical design procedure results in deterministic geometric parameters with tolerances normally chosen according to standards without due regard to their effects on the mission success as normally expressed by a reliability level. With the proposed design procedure, the engineer can specify nominal mean values for the geometric parameters and their tolerances according to a predetermined reliability level. Design nomographs are presented to help the engineer, in the early stages of design, to choose between many alternatives. Computer algorithms can easily be written to verify the final or optimum design.
Mathematical Model for Design Conditions for Cooling Load Calculations
Authors: Kohli D.
Published: January 2010

A numerical procedure using Newton-Raphson technique is used for finding wet bulb temperature from observed dry bulb temperature relative humidity and barometric pressure. Assuming maximum temperatures and daily temperature ranges of the day as random variables, maximum temperatures and daily ranges are estimated from samples of ten years data by t-distribution for various confidence limits. A parameter called “Average Hourly Temperature Deviation” is defined and its effect on Equivalent temperature differential is demonstrated. A mathematical model for finding out optimum daily temperature distribution has been developed. An average value of the “Average Hourly Temperature Deviation” is chosen as the optimality criterion. The procedures are demonstrated by numerical examples and the design conditions for 20 major cities of India are provided in tabular form.
Calculating Natural Frequencies With Extended Tuplin’s Method
Authors: Wang C. C.
Published: January 2010

In this paper an efficient numerical procedure is described which yields the eigenvalue of a lumped mass torsional vibration directly from the frequency equation of the system. Special characteristics of Tuplin’s frequency equation allow all eigenvalues to be easily located and accurately evaluated from the frequency polynomial. In contrast to the general belief that extracting roots of polynomials is less efficient than matrix reduction methods, this paper demonstrates that the direct solution competes favorably with the modern eigenvalue routines such as QR and tridiagonal methods [15] [16] [17] [21] in torsional vibration problems. A BASIC program FUNG has been written based on the numerical concepts of this paper. The current version is able to solve multiple branch systems of many degrees of freedom subject to the restriction that no branch shall exceed 4 rotors and 4 shafts. The program has been tested for various examples and the output compared with the known results. Within the above range of applicability, this method beats the modern tridiagonal eigenvalue subroutines [16] [21] by a comfortable margin which ranges from 15 times to 120 times faster. The comparisons were made on the basis of solving the same problems on the same computer. FUNG assumes a tight tolerance of convergence for iteration (correct to approximately 14 significant digits).
Evaluation of a High Performance Fixed-Ratio Traction Drive
Authors: Loewenthal S. H. , Anderson N. E. , Rohn D. A.
Published: January 2010

The results of a test program to evaluate a compact, high performance, fixed-ratio traction drive are presented. This transmission, the Nasvytis Multiroller Traction Drive, is a fixed-ratio, single-stage planetary with two rows of stepped planetrollers. Two versions of the drive were parametrically tested back-to-back at speeds to 73,000 rpm and power levels to 180 kW (240 hp). Parametric tests were also conducted with the Nasvytis drive retrofitted to an automotive gas turbine engine. The drives exhibited good performance, with a nominal peak efficiency of 94 to 96 percent and a maximum speed loss due to creep of approximately 3.5 percent.
Bending Fatigue Tests of High Speed Spur Gears
Authors: Yuruzume I. , Mizutani H.
Published: January 2010

Effects of addendum modification of tooth profiles on the bending fatigue strength of high speed spur gear are discussed in this presentation: A JIS Class O Spur gear of m3, α20 deg, Z1 27, and made of AMS 6260 (AISI 9310) steel precisely ground after carburizing and hardening was meshed with the other gear of Z2 77 and operated at 8550 rpm. In this running test, bending load capacity and running performance comparisons between the gear with standard tooth profile and the two shifted gears of which tooth addendum modification coefficients were 0.35 and 0.8. The maximum normal load of the gear with addendum modification coefficient 0.8 at 107 (10 million) cycles was 1.8 kNsmm per unit tooth width. The maximum Hertz stress of this gear was 2.43 × 109 Nsm2. The allowable normal load of the gear with 0.8 was higher than that of the standard gear by 87 percent and higher than of the 0.35 profile shifted gears by 20 percent.
Contact Stress Between Rollers With Surface Irregularity
Authors: Kubo A. , Okamoto T. , Kurokawa N.
Published: January 2010

To obtain fundamental data for research on surface durability of contacting bodies, contact stress between rollers with surface roughness or pit is analyzed. The increasing degree of contact stress owing to surface roughness is given by a non-dimensional factor, which is the ratio between maximum surface roughness and geometrical interpenetration of the contacting bodies. The contact stress concentration around a triangular pit is also discussed.
Endurance and Failure Characteristics of Modified Vasco X-2, CBS 600 and AISI 9310 Spur Gears
Authors: Townsend D. P. , Zaretsky E. V.
Published: January 2010

Gear endurance tests and rolling-element fatigue tests were conducted to compare the performance of spur gears made from AISI 9310, CBS 600 and modified Vasco X-2 and to compare the pitting fatigue lives of these three materials. Gears manufactured from CBS 600 exhibited lives longer than those manufactured from AISI 9310. However, rolling-element fatigue tests resulted in statistically equivalent lives. Modified Vasco X-2 exhibited statistically equivalent lives to AISI 9310. CBS 600 and modified Vasco X-2 gears exhibited the potential tooth fracture occurring at a tooth surface fatigue pit. Case carburization of all gear surfaces for the modified Vasco X-2 gears results in fracture at the tips of the gears.
Design and Evaluation of Drag-Link Driven Cams
Authors: Kwong C. W. , Wiederrich J. L. , Gupta K. C.
Published: January 2010

A systematic and rational method for designing drag-link driven cams for the purpose of modifying cam timing has been presented in this paper. In addition, two possible approaches for designing adjustable drag-link cam systems, namely uncompensated and compensated systems, have also been discussed. The performance comparisons for these linkages-cam systems are based upon pressure angle, cam size, input torque requirement, contact force and Fourier analysis of the follower acceleration.
Implementation of Solution Rectification Techniques in an Interactive Linkage Synthesis Program
Authors: Chuang J. C. , Strong R. T. , Waldron K. J.
Published: January 2010

The numerical and analytical problems encountered in the implementation of the theory developed by Strong and Waldron in an interactive graphic linkage synthesis program are discussed. The resulting program, called RECSYN, is more effective than earlier programs since the interactive experimentation capability no longer is needed to eliminate defective solutions but can be turned to other uses.
Results of an Industry/University Survey of Machine Systems Design Education
Authors: Guggenheim S.
Published: January 2010

Two surveys were conducted: one of instruction in machine systems design (MSD) and the other of employers of recently graduated design engineers who work as designers. Information was obtained on the faculty and the eductional undergraduate programs leading to a B.S. in Mechanical Engineering, and the information was subsequently compared to requirements for practice in the field as interpreted by employers. Both required and elective courses of instruction were categorized by topics covered, skills and attitudes developed, and credits given toward the degree. The corresponding needs of the practicing design engineer in like categories were determined from the survey of employers. Of the teaching faculty, 74 percent hold the Ph.D. and 56 percent are registered. The average faculty member has twice as many years of teaching experience as industrial practice experience, a unique characteristic of engineering education in the U.S. Ninety percent of the schools offer a course in mechanical design typically using Shigley’s text, Mechanical Engineering Design, and are, consequently, component design oriented. Only 9 percent of the credits for graduation are given for required courses in MSD. The university survey shows that very few schools give courses in engineering drawing or manufacturing processes. Interdisciplinary courses are also few. Employers reported only two out of the seven most frequently cited topics of instruction to have significance in industrial applications. Manufacturing processes was one of the courses most often regarded as missing. Educators and employers agree that written communication is a highly desirable skill. However, to the contrary, the need employers express for graphics, drafting, and sketching is not reflected in the instructional program. The extensive means employers use to encourage their engineers to advance their careers by registering and acquiring advanced education were also surveyed. The uniformity of MSD instruction reflected in the results of the survey appears to be unhealthy for U.S. industry. There should be more originality and opportunity for systems design. The near absence of courses in graphical communication skills and manufacturing process—basic tools for young engineers—can be expected to retard the reindustrialization needed in the U.S. to compete worldwide. The problem of training top students in topics and skills that are not generally considered college level but without which they function poorly in the outside world needs a solution.
A New Concept for Force Balancing Machines for Planar Linkages. Part 2: Application to Four-Bar Linkage and Experiment
Authors: Tricamo S. J. , Lowen G. G.
Published: January 2010

This paper represents Part 2 of a two-part investigation on balancing devices for planar linkages. The theory shown in Part 1 is applied to the development of an experimental machine for theoretically fully force balanced four-bar linkages. To accomodate the inaccuracies in the various experimental quantities, it became necessary to obtain the correction masses from overdetermined sets of shaking force equations. Minimax and least squares approaches were formulated and adapted for solution by an existing augmented Lagrangian penalty function code. Both methods reduced the magnitudes of the actual shaking force components by more than fifty percent.
Moments Between Impacting Rigid Bodies
Authors: Brach R. M.
Published: January 2010

It appears that all current literature in mechanics omits the effect of the moment developed between colliding rigid bodies. In many practical applications in design work, a significant moment can exist during impact and the impulse of the moment must be included in the equations for the change of angular momentum of each body. The general equations of impulse and momentum are presented for two rigid bodies colliding in planar motion. These reduce to six linear equations in the six unknown final velocities. The effect of the moment impulse on the angular velocities is taken into account through the use of a moment coefficient of restitution. This coefficient can take on realistic values between minus and plus one. Several examples are worked. An expression for the moment coefficient is derived for a vertically falling block which rebounds with a non zero angular velocity. This angular velocity is related to nonuniformities in the surface impacted by the block.
Thermal and Thermoelastic Analysis of Spheroidal Graphite Cast Iron and Light Alloy Pistons
Authors: Calderale P. M. , Garro A. , Vullo V.
Published: January 2010

The results of theoretical thermal, thermoelastic, and mechanical analyses of a spheroidal graphite cast iron piston and an equivalent light alloy piston used hitherto are reported. The theoretical analysis was carried out using the finite elements method. Results obtained were experimentally verified by subjecting a spheroidal graphite cast iron piston to a peculiar load condition. The maximum stress values were found to be about the same in both pistons; so there is reason to believe that the spheroidal graphite cast iron piston can meet the same design requirements and even offer better performances than the light alloy piston.
Monotonicity in Goal and Geometric Programming
Authors: Papalambros P.
Published: January 2010

The concept of monotonicity is applied to posynomial geometric programming establishing rules for constraint activity identification by inspection. The same concept applied to goal programming allows direct evaluation of deviational variables. Goal interpretation with dominance conditions obviates the use of deviational variables and permits easy parametric analysis. Examples for helical spring design and machining economics of a turning operation are presented.
Linkage Characteristic Polynomials: Assembly Theorems, Uniqueness
Authors: Yan H. S. , Hall A. S.
Published: January 2010

Several assembly theorems, for obtaining the linkage characteristic polynomial for a complex chain through a series of steps involving the known polynomials for subunits of the chain, are derived and presented. These theorems give insight into how the topological information concerning the linkage is stored in the polynomial and might contribute to the automated recognition of linkage structure in generalized computer-aided design programs. Based on graph theory, the characteristic polynomial cannot characterize the graph up to isomorphism. However, for practical applications in the field of linkage mechanisms, it is extremely likely that the characteristic polynomials are unique for closed connected kinematic chains without any overconstrained subchains.
The Determination of the Lewis Form Factor and the AGMA Geometry Factor J for External Spur Gear Teeth
Authors: Mitchiner R. G. , Mabie H. H.
Published: January 2010

This paper presents a simple and direct approach to the problem of the definition of the root profile for standard and nonstandard external spur gear teeth. Equations are developed for the location of the tooth center-line intercept at the constant-stress parabola. Also, the expression for the location of the point of tangency of the parabola with the root trochoid is given as well as the derivative of this expression. The AGMA Standards present charts of geometry factors, but the method by which these factors were determined is graphical and in some instances is not sufficiently accurate nor convenient to use. Although other investigators have considered this problem, their methods are either graphical or very complicated analytically. This treatment of the problem has been developed because it is not available in the open literature. Tables and charts are given for both Y and J factors for many profile variations.
Complex Number Synthesis of Four-Bar Path Generating Mechanisms Adjustable for Multiple Tangential Circular Arcs
Authors: Huston L. , Kramer S.
Published: January 2010

By combining complex number methods of synthesis [1] with graphical techniques, an adjustable, planar, four-bar path generating mechanism can be synthesized to produce symmetrical coupler curves that conform to a specified radius over a finite range. In this way the earlier works by Tao and Yan [2, 3] can be generalized for use by a large number of mechanism designers. The coupler point of the mechanism will trace any desired number of circular arcs that are tangential at a preselected point with prescribed radii of curvature (positive, negative, or infinite). In this development, components of this mechanism may be chosen freely or under certain parameters by one of three techniques presented here. Also available is an analysis to give coupler link rotation, output crank rotation, and coupler point location as a function of input crank rotation.
On Attempting to Reduce Undesirable Inertial Characteristics of the Schatz Mechanism
Authors: Baker J. Eddie , Duclong Tran , Khoo P. S. H.
Published: January 2010

Using the geometrical properties of the Schatz linkage, we develop expressions for the velocity and acceleration of the mass centre for each coupler and for the angular velocity and acceleration of each link. We attempt to reduce the serious inertial characteristics of the linkage by seeking an input pattern which decreases the magnitudes of acceleration components. We find that the most beneficial form of drive, under our criteria, is that which results from using a Hooke’s joint with a drive-shaft inclined at 45° to the input link. We employ the methods of classical mechanics to determine joint forces and input torque for a working model of the linkage for this case and for that with constant input angular velocity. We find that, despite the difference in acceleration characteristics, the consequent forces and torque for the two cases are practically identical. We subsequently determine locations of acceleration centres for the links as an indication of possible relationships with inertial properties. The result of this particular investigation leads us to also develop the equations of the axodes for the couplers.
Method of Determining Locations of Unbalances in Rotating Machines
Authors: Shiohata K. , Fujisawa F. , Sato K.
Published: January 2010

This paper presents a method of determining the locations of unbalances on a rotor when the unbalances occur abruptly during rotor running. The method makes use of journal vibrations, because, generally, there is a relation between the locations of unbalances and the unbalance vibration modes of a rotor. At critical speeds, where this relation is particularly significant, the phase angle of an unbalance vibration shifts 90 deg, and unbalance distributions excite vibration modes. Which mode or modes is excited depends on the location of an unbalance on a rotor. In this paper, a rotor is assumed to be divided lengthwise into three sections on which unbalances are assumed to be distributed. A simple algorithm, which is derived from the characteristics of the foregoing vibrations and assumptions, allows four unbalance distributions to be determined on a rotor, at the center, on the either side (right or left side), on the right and left sides (out of phase), and on the right and left sides (in phase) of a rotor.
Effect of Inter-Modulation and Quasi-Periodic Instability in the Diagnosis of Rolling Element Incipient Defect
Authors: Osuagwu C. C. , Thomas D. W.
Published: January 2010

The absence of significant peaks at the fundamental rotational frequencies, indicative of a particular defect such as an outer race fault, results in a failure of the power spectrum technique to detect and diagnose mechanical defects characterized by sounds of short duration. Based on the results of an incipient defect diagnosis, explanations are offered as to the cause of the missing fundamental in the power spectrum in terms of two different effects which may operate simultaneously; they are 1 An average and shift effect which causes a slow migration of the fundamental impact frequency from its computed value; and 2 An inter-modulation effect which translates defect related information to frequency locations unrelated to the fundamental impact frequency. The paper goes on to show that fault detection and diagnosis are possible despite the absence of a significant peak at the fundamental rotational frequency.
Use of Cepstra in Acoustical Signal Analysis
Authors: Lyon R. H. , Ordubadi A.
Published: January 2010

Cepstral Analysis is an example of nonlinear filtering that has been applied to extracting the properties of transmission path and source characteristics in acoustics. To see why this is so, we review some of the properties of linear windowing in the time and frequency domains with a view to revealing the limitations that these methods have. We then describe the cepstrum and the conditions under which it can be helpful in separating source and path characteristics. The method is illustrated by describing some applications. Finally, research directions that may help to extend the applicability of cepstral analysis to structural vibration transmission are discussed.
Transverse Vibrations of a General Cracked-Rotor Bearing System
Authors: Inagaki T. , Kanki H. , Shiraki K.
Published: January 2010

In this study, the steady state response to the gravity and the unbalance force, and the major natural vibration of a general rotor bearing system with the open or open-close type crack, is analyzed along the iterative numerical calculation method (the transfer matrix method). The open-close type crack is idealized as a step function of the bending moment. The nonlinear equations are linearized by using the Fourier expansion technique, and its solutions are given approximately with the static deflection, the once/rev. vibration, and the twice/rev. vibration. The analyzed calculated method is confirmed by comparing the calculations with the experiments for a small test rotor. The rotor bearing system model in this method is as accurate as the usual numerical rotor dynamic analysis model, and also the required procedures for the calculation are almost the same.
Large Amplitude Elliptical Plate Vibration With Transverse Shear and Rotatory Inertia Effects
Authors: Sathyamoorthy M.
Published: January 2010

An improved nonlinear vibration theory is used in the present analysis to study the effects of transverse shear deformation and rotatory inertia on the large amplitude vibration behavior of isotropic elliptical plates. When these effects are negligible the differential equations given here readily reduce to the well-known dynamic von Ka´rma´n equations. Based on a single-mode analysis, solutions to the governing equations are presented for immovably clamped elliptical plates by use of Galerkin’s method and the numerical Runge-Kutta procedure. An excellent agreement is found between the present results and those available for nonlinear bending and large amplitude vibration of elliptical plates. The present results for moderately thick elliptical plates indicate significant influences of the transverse shear deformation, axes ratio, and semi-major axis-to-thickness ratio on the large amplitude vibration of elliptical plates.
Analysis of Plate Vibrations Using Superelements
Authors: Pekau O. A. , Huttelmaier H. P.
Published: January 2010

A rectangular substructure or superelement is described for use in the vibrational analysis of plates and flat plate assemblies. Basic features include elimination of internal nodes and flexibility in the location of nodes along the boundaries. Illustrative examples demonstrate the efficient and versatile application of the element. The main focus, however, is on solution accuracy for different representations of mass. In particular, it is found that the homogeneous inertia properties of a plate must be expressed by a consistent substructure mass matrix in order to model dynamic properties accurately.
Eigenvalue Derivatives for Damped Torsional Vibrations
Authors: Doughty S.
Published: January 2010

In the design of rotating machinery, it is often necessary to project design changes in order to modify the system torsional natural frequencies. For damped systems, there are additional questions regarding the change in modal decay rates associated with a parameter change. This paper provides a simple, easily implemented procedure to calculate the derivatives of the complex eigenvalue for the damped torsional system when the eigensolution is known.
Rank Transformations of Order Statistics
Authors: Saringer J. H.
Published: January 2010

Distributions of order statistics are shown to describe themselves recursively; hence items of a population of one order statistic, when ordered, can themselves be described by distributions of order statistics. A transformation carried out analytically or with a simple Fortran algorithm supplied transforms ranks from one level to another, making it possible to describe an ordered item of a population, which is itself an order statistic of some larger population, in terms of the larger parent population itself. This process is described as a “rank transformation” where an item “rank” is defined as the proportion of the population falling below that item. Examples are presented that demonstrate applications of this technique to the analysis of accelerated life data, probability plotting, and analysis of systems with redundancy.
The Effects of Inherent Flaws on the Time and Rate Dependent Failure of Adhesively Bonded Joints
Authors: Sancaktar E. , Padgilwar S.
Published: January 2010

Experiments on single lap joints bonded with viscoelastic adhesives reveal that the effects of rate and time and inherent flaws are as critical in joint failure as are the environmental and stress concentration effects. Experimental data reveal that random inherent flaws and loading rate changes may result in as much as 40 percent reduction in joint strength. Furthermore when creep loading is used, the asymptotic creep stress, below which no delayed failure will occur, may have to be as much as 45 percent less than the adhesive maximum strength.
Predicting Fatigue Endurance Strengths for High- and Low-Cycle Fatigue
Authors: Mischke C. R.
Published: January 2010

The objective of this paper is to develop a single equation that can describe the endurance strength cycles-to-failure locus for steels. A designer can use this equation by having only static tensile test information and one point on the fatigue locus.
A Numerical Study on the Edge-Profile During Shearing of Bars Using the Principles of Linear Elastic Fracture Mechanics
Authors: Maiti S. K.
Published: January 2010

In this paper sheared edge-profiles of brittle bars are predicted using the principles of linear elastic fracture mechanics. The effects of several varying process parameters are also included.
Computer-Aided Design of Curved Surfaces With Automatic Model Generation
Authors: Staley S. M. , Jerard R. B. , White P. R.
Published: January 2010

The design and visualization of three-dimensional objects with curved surfaces have always been difficult. This paper describes a computer system that facilitates both the design and visualization of such surfaces. The system enhances the design of these surfaces by virtue of various interactive techniques coupled with the application of B-Spline theory. Visualization is facilitated by including a specially built model-making machine that produces three-dimensional foam models. Thus the system permits the designer to define an object and, with little additional effort, produce an inexpensive model of the object which is suitable for evaluation and presentation.
Error Linearization in the Least-Squares Design of Function Generating Mechanisms
Authors: Wilde D. J.
Published: January 2010

Minimum squared error mechanism synthesis can be done relatively easily by Error Linearization, a nonlinear regression procedure long known to statisticians. It has a descent property not possessed by the Newton-Raphson method, which consequently tends more readily to converge to unwanted stationary points. Applied to a four-bar function generator, error linearization yields, for the Freudenstein linear displacement equation, a least-squares design as a direct solution of three linear equations, whatever the number of design angle pairs. For the particular example considered, this design is mechanically unacceptable, but a good configuration is produced by a more natural nonlinear model in which angular error is the measure of performance. Here error linearization avoids nonoptimal local minima to which the Newton-Raphson method converges.
Resizing: Predicting a New Geometric Programming Optimum as Coefficients Vary
Authors: Wilde D. J.
Published: January 2010

Imagine that an optimal solution is available for a constrained geometric program, and suppose one wishes a satisfactory solution for greatly different values of some of the coefficients. An estimate can be constructed by using the values of the dual variables for the old optimum in the invariance conditions for the new problem. Although these are inconsistent except at the precise optimum, a unique primal solution can easily be generated from them by the method of least squares with individual equations weighted by the value of the corresponding dual variable. The matrix equations for these linear operations are derived and applied to a well-known merchant fleet design problem. The predictions are remarkably accurate—1.4 percent error for a 100 percent coefficient change.
A Minimax Approach to the Best Mechanical Alignment Problem
Authors: Bandler J. W. , El-Kady M. A. , Kellermann W. , Zuberek W. M.
Published: January 2010

This paper provides an attempt to formulate and to solve the best mechanical alignment problem, which arises in many practical situations when a relatively expensive manufactured product does not meet design specifications and a decision is to be made for partial retreatment of the product. We define and use concepts of regular points, reference points, and referenced points for a mechanical design. These points represent important features which must be reproduced subject to tolerances, which are defined with respect to (w.r.t.) various coordinate systems. The algorithm proposed identifies candidates for reworking using minimax optimization. While the concepts introduced and the method presented resulted from a variety of approaches to solving mechanical problems in two dimensions, this class of problem can arise in other areas and further generalization is possible.
Multiobjective Design Optimization of Machine-Tool Spindles
Authors: Yoshimura Masataka , Hamada Toshio , Yura Kenji , Hitomi Katsundo
Published: January 2010

A method of multiobjective design optimization is presented in order to evaluate conflicting objectives in designing machine-tool spindles. A Pareto optimum set which shows a trade-off relationship between two objectives minimizing the total weight of the spindle and the static torsional or bending compliance, is derived using the Kuhn-Tucker necessary conditions for optimality, and through analyses of objective and constraint functions. Weighting factors between the two objectives are obtained on the Pareto optimum set. Expanded problems and numerical examples are given.
An Automated Procedure for Local Monotonicity Analysis
Authors: Azarm S. , Papalambros P.
Published: January 2010

A strategy for selecting active constraints in a design optimization program is implemented computationally. The strategy uses local monotonicity information to iterate on the active set. A fully automated algorithm is developed with the aid of constrained derivatives and conventional search methods. Four design examples are presented, one of which demonstrates how global rules derived from monotonicity analysis can be included in the active set strategy to enhance the performance of the algorithm. The procedure is flexible, so that any available rules that can bias the selection of active sets may be included in the strategy.
Optimization of the Geometry of Shafts Using Boundary Elements
Authors: Mota Soares C. A. , Rodrigues H. C. , Oliveira Faria L. M. , Haug E. J.
Published: January 2010

The problem of the optimization of the geometry of shafts is formulated in terms of boundary elements. The corresponding nonlinear programming problem is solved by Pshenichny’s Linearization method. The advantages of the boundary element method over the finite element method for optimal design of shafts are discussed, with reference to the applications.
The Generalized Oldham Coupling
Authors: Freudenstein F. , Tsai L. W. , Maki E. R.
Published: January 2010

A new mechanism, which we have called the generalized Oldham coupling, has been described. With a circular-arc construction for its projections and grooves, the coupling has been shown to be analyzable in terms of an equivalent drag linkage, which is generally much larger than the coupling. The kinematic analysis of the coupling, including sliding motions, has been given and general considerations regarding transmission-angle optimization and dynamic equivalence have been pointed out. The application of the coupling to phase changing is reviewed and a general form of construction involving rollers has been described and shown to yield a phase-changing capability of a very general nature.
Assembly Integrity of Coaxial Rigid Parts Positioned by Congruent Conical Pilots. Part 2: F-F End Conditions
Authors: Ferrel R. S. , Davidson J. K.
Published: January 2010

Congruent conical pilots can be used to configure the contacting surfaces of coaxially assembled rigid cylindrical parts where assembly integrity is obtained by an axial clamping load and where externally applied constraints occur only at the ends of the assembly. The relative motion for mating parts is developed for parts of arbitrary length. A method for optimal geometric design of the pilots is presented for the special conditions that all the parts be of the same length and that the assembly contain the minimum number of parts permissible for instability to occur. Application of the optimal design method achieves the maximum stability in the presence of a lateral destabilizing load. For each part dimension, the optimal value is at a domain limit.
Optimal Design of a Mechanism Used for Opening and Shutting a Ship’s Hatch Cover
Authors: Ito Koichi , Kuroiwa Tadashi , Akagi Shinsuke
Published: January 2010

A nonlinear optimization method is proposed to design a linkage mechanism used for opening and shutting a ship’s hatch cover. Considering the maximum force of the oil cylinder necessary to move the hatch cover as the objective function to be minimized, the design problem to determine the optimal configuration of linkage mechanism is formulated as a nonlinear optimization problem of minimax type. It it shown that the optimal solution can be derived by adopting the generalized reduced gradient algorithm together with a linkage statical simulation model, and the effectiveness of the algorithm is ascertained through a numerical study.