Abstract:
A method of installing a bracket to an engine casing of a gas turbine engine includes attaching a first mount segment of a first bracket to an auxiliary component and attaching a second mount segment of the first bracket to the engine casing. In one exemplary embodiment, the method can include attaching a second bracket to the auxiliary component on an opposite side of the auxiliary component from the first bracket.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This is a divisional application of U.S. patent application Ser. No. 11/291,348, filed Dec. 1, 2005. 
     
    
     BACKGROUND 
       [0002]    This disclosure relates to a mounting system, and more particularly to an energy absorbing mount system for a gas turbine engine auxiliary component. 
         [0003]    Gas turbine aircraft engines utilize a turbine fan to draw ambient air into the engine for compression and combustion by the engine. The turbine fan is shrouded by an engine casing. Typically, a variety of auxiliary components such as engine oil tanks, gearboxes, valves, control systems for regulating the engine&#39;s operations, and other components are mounted to the engine casing. Various mounting systems mount the auxiliary components to the engine casing. 
         [0004]    Conventional mounting systems typically include a plurality of rigid bracket members that are attached between the auxiliary component and the engine casing by a series of shear pins. Such conventional mounting systems may also include isolators that damp the transmission of engine vibratory loads to the auxiliary components during normal loading and operating conditions. 
         [0005]    Conventional mounting systems may become subjected to a high degree of shock loading not experienced during normal engine operating conditions. For example, a high shock load may result from a fan-blade out event. A fan-blade out event occurs when a fan-blade breaks off of an engine rotor body as a result of impact with a foreign object. A fan-blade out event results in an imbalance in the engine rotor body which may also cause outward deflection and a rotor body shaft imbalance. 
       SUMMARY 
       [0006]    A method of installing a bracket to an engine casing of a gas turbine engine includes attaching a first mount segment of a first bracket to an auxiliary component and attaching a second mount segment of the first bracket to the engine casing. In one exemplary embodiment, the method can include attaching a second bracket to the auxiliary component on an opposite side of the auxiliary component from the first bracket. 
         [0007]    The various features and advantages of this disclosure will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a perspective view of a gas turbine engine assembly having an auxiliary component for mounting on the engine&#39;s external casing; 
           [0009]      FIG. 2  is a top view of a portion of a gas turbine engine assembly having an auxiliary component mounted to the engine casing with a mount system according to the present invention; 
           [0010]      FIG. 3  is a side view of the assembly illustrated in  FIG. 2 ; 
           [0011]      FIG. 4  is a perspective view of a top bracket position with respect to an auxiliary component and an engine casing; 
           [0012]      FIG. 5  is a bottom view of a portion of a gas turbine engine having an auxiliary component mounted to the engine casing with the mount system according to the present invention; 
           [0013]      FIG. 6  is a perspective view of a side bracket according to the present invention; 
           [0014]      FIG. 7  is a perspective view of the side bracket of the present invention after experiencing a high shock loading event. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Referring to  FIG. 1 , a gas turbine engine  10  generally includes a fan section  12 , a compressor section  14 , a combustion section  16  and a turbine section  18 . The compressor section  14  and the turbine section  18  each contain one or more stages of a compressor and a turbine (not shown) which rotate about an engine longitudinal axis  20 . The components of the gas turbine engine  10  are circumscribed by an essentially cylindrical engine casing  22 . The engine casing  22  serves as a main structural support for the gas turbine engine  10 . The engine casing  22  is usually constructed of individual case sections, such as case sections  24  and  26 , which are joined together at bolted flanges such as engine case flange  30 . 
         [0016]    An auxiliary component  32  is mounted to the engine casing  22  by a mount system  40  along an auxiliary component axis A which is generally transverse to the engine longitudinal axis  20 . The auxiliary component  32  may include any component known in the art that requires mounting to the engine casing  22 , including but not limited to an oil tank, a gearbox, valves and electronic control systems for regulating the operations of the gas turbine engine  10 , and may be mounted in any orientation. 
         [0017]    Referring to  FIG. 2 , a three-point mount system  40  includes side brackets  42 ,  44  and a top bracket  46 . It should be understood that fewer or additional brackets may be utilized to mount an auxiliary component  32  within the contemplation of this invention. One side bracket  42 ,  44  is positioned on each side of the auxiliary component  32 , forward and aft thereof relative to the gas turbine engine longitudinal axis  20 . The side brackets  42 ,  44  are preferably positioned on each side of the auxiliary component  32  center of gravity. It should be understood that the position of the side brackets  42 ,  44  may vary depending upon the size and shape of the auxiliary component  32 . Generally, the side brackets  42 ,  44  are positioned nearest to the average location of the weight of the auxiliary component  32  as possible without interfering with design functionality. By positioning the side brackets  42 ,  44  near the average location of the weight of the auxiliary component, the side brackets  42 ,  44  provide a rigid attachment of the auxiliary component  32  to the engine casing  22  during normal engine operation to generally reduce vibration therefrom. 
         [0018]    Referring to  FIG. 3 , the top bracket  46  is located axially forward of the side brackets  42 ,  44  along the axis A of the auxiliary component  32 . The top bracket  46  is positioned generally parallel relative to the engine longitudinal axis  20  of the gas turbine engine  10  near a top end segment  51  of the auxiliary component  32 . It should be understood that other orientation and bracket combinations will also be usable with the present invention. 
         [0019]    Referring to  FIG. 4 , the top bracket  46  includes a set of arms  57 ,  59  and a neck portion  61 . The set of arms  57 ,  59  are each attached to a separate engine case flange  30 . The set of arms  57 ,  59  of the top bracket  46  engage the auxiliary component  32  through a multitude of fasteners F to provide a relatively flexible cradle between the auxiliary component  32  and the engine casing  22 . That is, the side brackets  42 ,  44  are the primary supports for the auxiliary component  32  while the top bracket  46  generally stabilizes the auxiliary component therebetween. 
         [0020]    The bracket components, including the side brackets  42 ,  44  and the top bracket  46 , are preferably constructed of a sheet metal material. The brackets can be made entirely from AMS5599, Inconel 625 (nickel-alloy). This material is well suited for the present invention, because of its relative stiffness while simultaneously having a high plasticity and good fatigue properties. It should be understood that other materials and combinations thereof may be utilized to construct the brackets of the mount system of the present invention. 
         [0021]    Referring to  FIG. 5 , the auxiliary component  32  is here mounted to the engine casing  22  such that the auxiliary component axis A (extending into the page) is transverse to the engine longitudinal axis  20  of the engine casing  22 . It should be understood that various mounting arrangements are possible for the auxiliary components, and may depend on design specific parameters. The side brackets  42 ,  44  are aligned generally along the engine longitudinal axis  20  of the engine casing  22  and on each side of the auxiliary component axis A. 
         [0022]    Each side bracket  42 ,  44  defines a first mount segment  50  and a second mount segment  52 . The first and second mount segments  50 ,  52  are planar members which are generally parallel to one another. The first mount segment  50  attaches to the auxiliary component  32  and the second mount segment  52  attaches to the engine casing  22 . Preferably, the mount segments  50 ,  52  are fastened to the auxiliary component  32  and the engine casing  22 , respectively through a plurality of apertures formed in the mount segments  50 ,  52  (also illustrated in  FIG. 6 ). 
         [0023]    The side brackets  42 ,  44  are manufactured of three layers, although it should be understood that any number of layers may be used to form the mount segments  50 ,  52 . The layers are preferably riveted together at rivets R ( FIG. 6 ) to maintain the structural integrity of the mount segments  50 ,  52 ; however, other attachments including welding may also be utilized to sandwich the layers of the brackets  42 ,  44 . The mount segments  50 ,  52  may include weight reducing openings  53  to still further reduce the overall weight of the side brackets  42 ,  44 . The construction of the side brackets  42 ,  44  preferably requires no welding, brazing or the like. The side brackets  42 ,  44  are assembled from three pieces of sheet metal. Separation of the individual segments of the side brackets  42 ,  44  as hereinabove described is for purposes of description only. 
         [0024]    Each side bracket  42 ,  44  includes a deformable member  60  sandwiched between a first and a second retainer member  62 ,  64 . The deformable member  60  defines a planar segment  74  which extends transversely to the mount segments  50 ,  52 . The deformable member  60  is sandwiched between a first retainer member  62  and a second retainer member  64 . The retainer members  62  and  64  include at least partially non-planar segments  72  between the mount segments  50 ,  52 . The non-planar segments  72  flank but are separated from the planar segment  74  of the deformable member  60  between the planar mount segments  50 ,  52 . That is, the retainer members  62 ,  64  sandwich the deformable member  60  therebetween to provide a laminated side bracket  42 ,  44  design. 
         [0025]    The planar segment  74  of the deformable member  60  defines a series of openings  70  generally transverse to the mount segments  50 ,  52 . The size and quantity of the openings  70  is determined by application specific parameters including the shear strength and the load strength of the material used to fabricate the deformable member  60  and the magnitude of the shock loads expected to be experienced by the deformable member  60 . It should be understood that the deformable member  60  may be designed with a single opening or without any openings  70  by utilizing a more brittle material as a substitute for the nickel-alloy sheet metal material preferably used to fabricate the deformable member  60 . In one example, titanium is substituted as the material for the deformable member  60 . The deformable member  60  is designed to reach ultimate strain at a predetermined load that is expected to be experienced during a particular high shock load such as during a fan-blade out event. 
         [0026]    The first retainer member  62  and the second retainer member  64  are disposed on each side of the deformable member  60  to sandwich the deformable member  60  therebetween. The retainer members  62 ,  64  each include the non-planar segment  72  adjacent the planar segment  74  of the deformable member  60 . Preferably, the non-planar segments  72  are pre-formed sections that to include an arcuate bend. 
         [0027]    During normal engine operation, the side brackets  42 ,  44  and the top bracket  46  are sufficiently stiff to rigidly support the auxiliary component  32 . The retainer members  62 ,  64  and the deformable member  60  of the side bracket  42 ,  44  provide the necessary rigidity to support the auxiliary component  32  relative to the engine casing  22 . 
         [0028]    Referring to  FIG. 7 , the side bracket  42 ,  44  is illustrated after being subjected to a fan-blade out event. That is, the openings  70  provide a predefined failure area. Relatively severe engine rotor imbalance occurs due to the fan-blade out event such that the deformable member  60  may tear, shear, buckle, fuse or otherwise deform in tension along the openings  70 . The plastic deformation of the deformable member  60  absorbs a majority of the high shock load. The balance of the shock loads are absorbed by the retainer members  62 ,  64  in which the non-planar segments  72  of the retainer members  62 ,  64  extend (illustrated schematically by arrow B) and collapse toward or bulge away from each other to provide a further load absorption path. That is, the combination of the deformable member  60  failure and extension of the non-planar segments  72  of the retainer members  62 ,  64  absorb the high shock load by essentially extending the time period of the high shock load event. The retainer members  62 ,  64  also retain the auxiliary component  32  to the engine casing  22  subsequent to the fan-blade out event such that the auxiliary component  32  does not break completely free. In this way, the mount system  40  may be sacrificed while the integrity of the auxiliary component  32  is maintained. 
         [0029]    The foregoing shall be interpreted as illustrative and not in a limiting sense. A worker of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.