Patent Publication Number: US-11384658-B1

Title: Deformable bumper for a rotating structure of a turbine engine

Description:
TECHNICAL FIELD 
     This disclosure relates generally to a turbine engine and, more particularly, to a bearing support for a turbine engine. 
     BACKGROUND 
     A gas turbine engine includes a stationary structure and a rotating structure rotatably mounted with the stationary structure via a plurality of bearings. Under certain conditions, one or more portions of the rotating structure may vibrate, wobble and/or otherwise shift relative to the stationary structure. Various devices and systems are known in the art for accommodating and/or controlling such shifting between the rotating structure and the stationary structure. While these known devices and systems have various benefits, there is still room in the art for improvement. 
     SUMMARY OF THE DISCLOSURE 
     According to an aspect of the present disclosure, an assembly is provided for a turbine engine. This turbine engine assembly includes a stationary structure, a rotating structure and a bearing. The rotating structure rotatable about an axis relative to the stationary structure. The bearing supports the rotating structure. The stationary structure includes a flexible bearing support and a crushable bumper. The flexible bearing support supports the bearing. The crushable bumper is arranged radially outward of and axially overlaps the flexible bearing support. The stationary structure is configured such that: the flexible bearing support is disengaged from the crushable bumper during a first mode of operation; and the flexible bearing support contacts the crushable bumper during a second mode of operation. 
     According to another aspect of the present disclosure, another assembly is provided for a turbine engine. This turbine engine assembly includes a rotating structure, a bearing and a stationary structure. The bearing supports the rotating structure. The stationary structure includes a bearing support and a bumper. The bearing support is cantilevered from another portion of the stationary structure. The bearing support includes a plurality of beams and a bearing support section. The beams are distributed circumferentially about an axis and project axially along the axis to the bearing support section. The bearing is mounted to the bearing support section at an unsupported end of the bearing support. The bumper is configured to deform when the bearing support section subjects the bumper to a radial load over a threshold. 
     According to still another aspect of the present disclosure, another assembly is provided for a turbine engine. This turbine engine assembly includes a rotating structure, a bearing, a bearing support and a deformable bumper. The bearing supports the rotating structure. The bearing support supports the bearing. The deformable bumper is configured to damp radial movement of the bearing support. The deformable bumper includes a porous structure with an inner portion and an outer portion. The inner portion is radially between the outer portion and the bearing support. The inner portion has an inner portion density. The outer portion has an outer portion density that is different than the inner portion density. 
     An annular gap may be formed radially between the flexible bearing support and the crushable bumper during the first mode of operation. 
     The flexible bearing support may also be configured to crush the crushable bumper during the second mode of operation. 
     The flexible bearing support may also be configured to permanently deform the crushable bumper during the second mode of operation. 
     The crushable bumper may circumscribe the flexible bearing support. 
     A first portion of the crushable bumper may be configured to crush when subject to a first load. A second portion of the crushable bumper may be configured to crush when subject to a second load that is different than the first load. 
     The first load may be greater than the second load. The first portion of the crushable bumper may be arranged radially between the second portion of the crushable bumper and the flexible bearing support. 
     The first load may be greater than the second load. The second portion of the crushable bumper may be arranged radially between the first portion of the crushable bumper and the flexible bearing support. 
     The first portion of the crushable bumper may include a first cavity with a first dimension in a direction. The second portion of the crushable bumper may include a second cavity with a second dimension in the direction. The second dimension may be different than the first dimension. 
     The first portion of the crushable bumper may have a first porosity. The second portion of the crushable bumper may have a second porosity that is different than the first porosity. 
     The first portion of the crushable bumper may include an empty cavity. The second portion of the crushable bumper may include a cavity at least partially filled with filler material. 
     The crushable bumper may be configured from or otherwise include honeycomb. 
     The crushable bumper may be configured from or otherwise include foam. 
     The crushable bumper may be configured from or otherwise include a lattice structure. 
     The stationary structure may also include a fixed support. The crushable bumper may be mounted to the fixed support. 
     A radial outer side of the fixed support may be configured to form a peripheral boundary of a flowpath within the turbine engine. 
     The flexible bearing support may be a cantilevered from another portion of the stationary structure. The bearing may be supported by a distal, unsupported end portion of the flexible bearing support. 
     The flexible bearing support may include a mount section, a bearing support section and a spring section axially between and connected to the mount section and the bearing support section. The bearing may be mounted to the bearing support section. The spring section may include a plurality of slots arranged circumferentially about a rotational axis of the rotating structure. Each of the slots may extend radially through the spring section. 
     The present disclosure may include any one or more of the individual features disclosed above and/or below alone or in any combination thereof. 
     The foregoing features and the operation of the invention will become more apparent in light of the following description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial sectional illustration of an assembly for a turbine engine. 
         FIG. 2  is a perspective illustration of a bearing support connected to another portion of a stationary structure. 
         FIG. 3  is a side illustration of a portion of the bearing support. 
         FIG. 4  is a sectional illustration of another portion of the bearing support. 
         FIG. 5  is an end illustration of a bumper. 
         FIGS. 6A-D  are partial sectional illustrations of the turbine engine assembly during different modes of operation. 
         FIG. 7A  is a side illustration of a portion of the bumper configured from honeycomb. 
         FIG. 7B  is a sectional illustration of the bumper portion of  FIG. 7A . 
         FIG. 8A  is a sectional illustration of a portion of the bumper configured from open-cell foam. 
         FIG. 8B  is a sectional illustration of a portion of the bumper configured from closed-cell foam. 
         FIG. 9  is a perspective illustration of a portion of the bumper configured from a lattice structure. 
         FIG. 10  is a sectional illustration of a portion of the bumper configured with a radially uniform construction. 
         FIGS. 11-13  are sectional illustrations of portions of the bumper configured with radially varied constructions. 
         FIG. 14  is a schematic sectional illustration of a turbofan gas turbine engine. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an assembly  20  for a turbine engine. This turbine engine assembly  20  includes a rotating structure  22 , a stationary structure  24  and at least one bearing  26  rotatably mounting the rotating structure  22  with the stationary structure  24 . 
     The rotating structure  22  extends axially along and is rotatable about a rotational axis  28 , which rotational axis  28  may be coaxial with an axial centerline of the turbine engine assembly  20 . The rotating structure  22  of  FIG. 1  includes a shaft  30  and a second component  32 . Examples of the second component  32  of the rotating structure  22  include, but are not limited to, a sleeve, a spacer, a baffle, another shaft, a coupling, a seal land and a retainer (e.g., a clip, a nut, etc.). 
     The shaft  30  of  FIG. 1  includes a (e.g., tubular) shaft base  34  and a (e.g., annular) shaft shoulder  36 . The shaft base  34  extends axially along and circumferentially about (e.g., completely around) the rotational axis  28 . The shaft base  34  extends radially between and to an inner side  38  of the shaft  30  and an outer side  40  of the shaft base  34 . The shaft inner side  38  of  FIG. 1  forms an internal bore  42  within the shaft  30 , which internal bore  42  extends axially within (e.g., and into, or through) the shaft  30  and its shaft base  34 . 
     The shaft shoulder  36  is connected to the shaft base  34  at the base outer side  40 . The shaft shoulder  36  of  FIG. 1  projects radially out from the shaft base  34  and its base outer side  40  to a distal end  44  of the shaft shoulder  36 . The shaft shoulder  36  of  FIG. 1  extends axially along the rotational axis  28  between and to a first side  46  of the shaft shoulder  36  and a second side  48  of the shaft shoulder  36 . The shaft shoulder  36  may extend circumferentially about (e.g., completely around) the rotational axis  28 . 
     The stationary structure  24  of  FIG. 1  includes a bearing support  50 , a fixed support  52  and a bumper  54 . 
     The bearing support  50  of  FIG. 1  is cantilevered from another portion  56  of the stationary structure  24 . The bearing support  50 , for example, projects axially along the rotational axis  28  out from the stationary structure portion  56  to a distal (e.g., unsupported) end  58  of the bearing support  50 . Referring to  FIG. 2 , the bearing support  50  extends circumferentially about (e.g., completely around) the rotational axis  28 , thereby providing the bearing support  50  with a tubular body. The bearing support  50  may be configured as a flexible bearing support. The bearing support  50  of  FIG. 2 , for example, includes a mount section  60 , an intermediate (e.g., spring) section  62  and a bearing support section  64 . 
     The mount section  60  extends axially along the rotational axis  28  between and to the stationary structure portion  56  and the intermediate section  62 . The mount section  60  is connected to (e.g., formed integral with or otherwise attached to) the stationary structure portion  56  and the intermediate section  62 . The mount section  60  thereby connects and structurally ties the bearing support  50  to the stationary structure portion  56 . The mount section  60  of  FIG. 2  extends circumferentially about (e.g., completely around) the rotational axis  28 , and may be circumferentially and/or axially uninterrupted. 
     The intermediate section  62  extends axially along the rotational axis  28  between and to the mount section  60  and the support section  64 . The intermediate section  62  is connected to (e.g., formed integral with or otherwise attached to) the mount section  60  and the support section  64 . The intermediate section  62  thereby connects and structurally ties the support section  64  to the mount section  60 . Furthermore, under normal operating conditions, the intermediate section  62  may provide the only structural support for the support section  64  given, for example, the cantilevered connection of the bearing support  50  to the stationary structure portion  56 . The intermediate section  62  of  FIG. 2  extends circumferentially about (e.g., completely around) the rotational axis  28 , and may be circumferentially and/or axially interrupted; e.g., configured as a squirrel cage spring. The intermediate section  62  of  FIG. 2 , for example, includes a plurality of beams  66  and/or a plurality of slots  68 . 
     The beams  66  and the slots  68  are distributed circumferentially about the rotational axis  28 . The beams  66  are interspersed with the slots  68  such that: (A) each of the beams  66  is disposed and extends laterally (e.g., circumferentially or tangentially) between a respective lateral neighboring (e.g., adjacent) pair of the slots  68 ; and (B) each of the slots  68  is disposed and extends laterally within the intermediate section  62  between a respective laterally neighboring pair of the beams  66 . Each of the beams  66  extends axially along the rotational axis  28  between and is connected to the mount section  60  and the support section  64 . Each of the slots  68  extends axially along the rotational axis  28  within the bearing support  50  (and through the intermediate section  62 ) between and to the mount section  60  and the support section  64 . Referring to  FIG. 1 , each of the slots  68  extends (e.g., completely) radially through the bearing support  50  and its intermediate section  62  between and to an inner side  70  of the intermediate section  62  and an outer side  72  of the intermediate section  62 , which may also be an outer side  74  of the bearing support  50 . 
     Referring to  FIG. 3 , each of the beams  66  has a longitudinal length  76  and a lateral width  78 . The beam longitudinal length  76  is measured along a longitudinal centerline  80  of the respective beam  66  from the mount section  60  to the support section  64 . Each beam longitudinal centerline  80  of  FIG. 3  is straight and parallel with the rotational axis  28 ; however, the present disclosure is not limited to such an exemplary configuration. The beam lateral width  78  is measured between opposing lateral sides of the respective beam  66 ; e.g., between the respective laterally neighboring pair of the slots  68 . 
     Each of the slots  68  has a longitudinal length  82  and a lateral width  84 , where the slot longitudinal length  82  is equal to the beam longitudinal length  76  and the slot lateral width  84  may be equal to or different (e.g., greater or less) than the beam lateral width  78 . The slot longitudinal length  82  is measured along a longitudinal centerline  86  of the respective slot  68  from the mount section  60  to the support section  64 . Each slot longitudinal centerline  86  of  FIG. 3  is straight and parallel with the rotational axis  28 ; however, the present disclosure is not limited to such an exemplary configuration. The slot lateral width  84  is measured between opposing lateral sides of the respective slot  68 ; e.g., between the respective laterally neighboring pair of the beams  66 . 
     The dimensions (e.g.,  76 ,  78 ,  82 ,  84 ) of the beams  66  and the slots  68  are selected to tune the intermediate section  62  to provide the bearing support  50  with a certain amount of flexibility. For example, referring to  FIG. 1 , the intermediate section  62  and its beams  66  may be configured to facilitate a certain degree of twist between the support section  64  and the mount section  60  about the rotational axis  28 . The intermediate section  62  and its beams  66  may also or alternatively be configured to facilitate a certain degree of radial displacement between the support section  64  and the mount section  60 . The intermediate section  62  may thereby accommodate slight shifts between and/or vibrations in the rotating structure  22  and the stationary structure  24 . 
     The support section  64  of  FIG. 2  extends axially along the rotational axis  28  between and to the intermediate section  62  and the support distal end  58 . The support section  64  of  FIG. 2  extends circumferentially about (e.g., completely around) the rotational axis  28 , and may be circumferentially and/or axially uninterrupted. The support section  64  of  FIG. 1  includes a support section base  88 , a support section shoulder  90  and a support section slot  92 . 
     The section base  88  extends axially along and circumferentially about (e.g., completely around) the rotational axis  28 . The section base  88  extends radially between and to an inner side  94  of the section base  88  (e.g., the intermediate section inner side  70 ) and the support outer side  74 . 
     The section shoulder  90  is connected to the section base  88  at the base inner side  94 . The section shoulder  90  of  FIG. 1  projects radially inward from the section base  88  and its base inner side  94  to a distal end  96  of the section shoulder  90 . The section shoulder  90  of  FIG. 1  extends axially along the rotational axis  28  between and to a first side  98  of the section shoulder  90  and a second side  100  of the section shoulder  90 . The section shoulder  90  may extend circumferentially about (e.g., completely around) the rotational axis  28 . 
     The section slot  92  is arranged at (e.g., on, adjacent or proximate) the support distal end  58 . The section slot  92  extends circumferentially about (e.g., completely around) the rotational axis  28  within the section base  88 . Referring to  FIG. 4 , the section slot  92  extends axially along the rotational axis  28  within the section base  88  between and to opposing sides  102  and  104  of the section slot  92 . The section slot  92  projects radially into the section base  88  from the support inner side  94  to an end  106  of the section slot  92 . Referring again to  FIG. 1 , the section slot  92  may be configured as a receptacle for an annular retainer  108  (e.g., a split ring). 
     The fixed support  52  may be structurally tied to the stationary structure portion  56 . The fixed support  52  of  FIG. 1  extends axially along the rotational axis  28 . The fixed support  52  extends circumferentially about (e.g., completely around) the rotational axis  28 . The fixed support  52  projects radially inward (e.g., towards the rotational axis  28 ) to an inner side  110  of the fixed support  52 . The fixed support  52  may project radially outwards (e.g., away from the rotational axis  28 ) to an outer side  112  of the fixed support  52 . This fixed support outer side  112  may form a (e.g., inner) peripheral boundary of a volume  114  outside of a bearing compartment  116  housing the bearing  26 , which volume  114  may be a flowpath  116  within the turbine engine. 
     The bumper  54  extends axially along the rotational axis  28  between and to opposing ends  118  and  120  of the bumper  54 . Referring to  FIG. 5 , the bumper  54  extends circumferentially about (e.g., completely around) the rotational axis  28 , thereby providing the bumper  54  with a full hoop body. The bumper  54  of  FIGS. 1 and 5  is circumferentially and/or axially uninterrupted, and may be forms as a single unitary (e.g., monolithic) body. The bumper  54  of  FIG. 1  extends radially between and to an inner side  122  of the bumper  54  and an outer side  124  of the bumper  54 . 
     Referring to  FIGS. 6A-D , the bumper  54  is configured as a (e.g., permanently) deformable body. More particularly, the bumper  54  may be configured as a (e.g., radially) crushable body. The bumper  54  may have various configurations to tune its deformation (e.g., crushability), various examples of which are described below with reference to  FIGS. 7A-13 . The present disclosure, however, is not limited to such exemplary bumper configurations. 
     The bumper outer side  124  of  FIG. 1  may be abutted against and/or otherwise radially engage (e.g., contact) the fixed support  52  and its inner side  110 . The bumper  54  is also mounted to the fixed support  52 . The bumper  54 , for example, may be fixedly secured to the fixed support  52  through a mechanical coupling (e.g., via interference fit, mechanical fastener, etc.), a bond (e.g., weld, braze, adhesive, etc.) joint and/or any other attachment technique. 
     The bumper  54  of  FIG. 1  is radially outboard of and extends circumferentially about (e.g., completely around) each of the turbine engine assembly elements  22 ,  26 ,  30 ,  50  and  64 . The bumper  54  is axially aligned with the bearing support  50  and its support section  64 . The bumper  54  of  FIG. 1 , for example, axially overlaps the support section  64  at (or near) the support distal end  58 . 
     The bearing  26  may be configured as a roller element bearing. The bearing  26  of  FIG. 1 , for example, includes a (e.g., tubular) inner race  126 , a (e.g., tubular) outer race  128  and a plurality of bearing elements  130 . These bearing elements  130  are arranged circumferentially about the rotational axis  28  in an annular array. The bearing elements  130  are located radially between and radially engaged with the inner race  126  and the outer race  128 . 
     The inner race  126  is mounted to the rotating structure  22 . The inner race  126  of  FIG. 1 , for example, circumscribes and radially engages (e.g., contacts) the shaft base  34  and a surface thereof at its outer side  40 . The inner race  126  is axially captured and clamped between the shaft shoulder  36  and the second component  32  of the rotating structure  22 . The inner race  126  may thereby be fixed to and rotatable with the rotating structure  22 . 
     The outer race  128  is mounted to the stationary structure  24  and, more particularly, to the support section  64  at (e.g., on, adjacent or proximate) the support distal end  58 . The outer race  128  of  FIG. 1 , for example, is arranged within a bore of the bearing support  50  and its support section  64 , which support section  64  circumscribes and radially engages (e.g., contacts) the outer race  128  and an outer surface thereof. The outer race  128  is axially captured and clamped between the section shoulder  90  and the retainer  108 . The outer race  128  may also or alternatively be mechanically fixed (e.g., press fit) into the bore of the support section  64 . The outer race  128  may thereby be fixed to the stationary structure  24  and its bearing support  50 . 
     Referring to  FIG. 6A , during a mode of nominal (e.g., normal) turbine engine operation as well as when the turbine engine is non-operational, the bumper  54  is radially displaced from the bearing support  50  and its support section  64  by an (e.g., annular) air gap  132 . This air gap  132  has a height  134  with a first value. This gap height  134  extends radially between and to an (e.g., cylindrical) outer surface  136  of the support section  64  at the support outer side  74  and an (e.g., cylindrical) inner surface  138  of the bumper  54  at the bumper inner side  122 . The air gap  132  extends axially along the surfaces  136  and  138  for a (e.g., entire) length  140  of the bumper  54 , which bumper length  140  extends between and to the bumper sides  118  and  120 . The air gap  132  extends circumferentially about (e.g., completely around) the rotational axis  28 , thereby forming the air gap  132  as an annulus which circumscribes the support section  64 . 
     With the arrangement of  FIG. 6A , the bumper  54  is (e.g., completely) structurally disengaged from (e.g., does not contact and/or structurally support) the bearing support  50  and its support section  64 . The bumper  54  also has a height  142  with a first value. This bumper height  142  extends radially between and to the bumper inner side  122  and the bumper outer side  124 . 
     Referring to  FIG. 6B , during a first mode of off-nominal (e.g., abnormal) turbine engine operation, a first (e.g., shock and/or imbalance) load may radially displace the rotating structure  22  (see  FIG. 1 ). This first load is equal to or greater than a first threshold, but less than a second threshold. The first load may be generated during and/or follow from an off-nominal operating condition and/or event such as, but not limited to, a partial blade off event and/or a relatively large rotating structure imbalance. The radial displacement of the rotating structure  22  displaces the bearing  26  and the bearing support  50  radially outward. The support section  64  and its outer surface  136  may thereby temporarily radially engage (e.g., contact) the bumper  54  and its inner surface  138 . 
     During the first mode of off-nominal turbine engine operation, the bumper  54  provides a radial stop (e.g., a bump stop) for the rotating structure radial displacement. While the bumper  54  may slightly deform upon initial engagement (e.g., impact) between the surfaces  136  and  138 , this deformation may be elastic/resilient. Thus, the bumper height  142  may have a second value that is substantially (e.g., +/−2%) or exactly equal to the bumper height first value. A configuration of the bumper  54  may thereby remain substantially unchanged between the mode of nominal turbine engine operation and the first mode of off-nominal turbine engine operation. 
     Referring to  FIG. 6C , during a second mode of off-nominal turbine engine operation, a second (e.g., shock and/or imbalance) load may radially displace the rotating structure  22  (see  FIG. 1 ). This second load is equal to or greater than the second threshold. The second load may be generated during and/or follow from an off-nominal operating condition and/or event such as, but not limited to, a full blade off event. The radial displacement of the rotating structure  22  displaces the bearing  26  and the bearing support  50  radially outward. The support section  64  and its outer surface  136  may thereby temporarily radially engage (e.g., contact) the bumper  54  and its inner surface  138 . 
     During the second mode of off-nominal turbine engine operation, the bumper  54  again provides a radial stop for the rotating structure radial displacement. The bumper  54  may also provide a damper (e.g., a shock absorber) for the displaced rotating structure  22 . For example, where an impact and/or pressure force of the support section  64  against the bumper  54  is equal to or greater than a deformation threshold, the bumper  54  may (e.g., permanently) deform radially outward. The radial displacement of the rotating structure  22 , more particularly, presses the support section  64  radially against and at least partially crushes the bumper  54 . This crushing may provide a relatively gradual braking effect for the radial rotating structure displacement, as compared to the support section  64  hitting against a non-deformable stop. Providing such a gradual braking effect may reduce or prevent further damage to the rotating structure  22  and/or other components of the turbine engine. The crushing may also tune a response of the rotating structure  22 , for example, by changing rotor-dynamic modes. Following this deformation (e.g., crushing), the bumper height  142  has a third value that is less than the bumper height first and second values. The bumper height third value, for example, may be less than four-fifths (⅘), two-thirds (⅔), one-half (½), one-third (⅓) or otherwise of the bumper height first value. The present disclosure, however, is not limited to the foregoing exemplary dimensional relationship. 
     Referring to  FIG. 6D , following the second mode of off-nominal turbine engine operation, the bumper  54  may remain substantially or completely deformed. The bumper height  142 , for example, may have a fourth value that is substantially (e.g., +/−2%) or exactly equal to the bumper height third value. Thus, when the turbine engine is non-operational for example, the gap height  134  has a second value that is greater than the gap height first value (see  FIG. 6A ) prior to the deformation (e.g., crushing) of the bumper  54 . 
     Referring to  FIGS. 7A-9 , the bumper  54  is configured with a porous body. The bumper  54  of  FIGS. 7A-9 , for example, includes a plurality of internal cavities  144  (e.g., pores, chambers, interstices), which cavities  144  provide space for the bumper  54  to deform; e.g., crush. One or more of the cavities  144  may be configured as separate, fluidly discrete cavities. One or more of the cavities  144  may also or alternatively be fluidly coupled with another one or more of the cavities  144 ; e.g., the cavities  144  may be interconnected to provide a volume. The bumper  54  is constructed from a bumper material such as, but not limited to, a metal, a polymer, a composite material or a combination thereof. 
     In some embodiments, referring to  FIGS. 7A and 7B , the bumper  54  may be configured with or otherwise include honeycomb  146 ; e.g., a honeycomb body. Each cavity  144  of  FIG. 7A , for example, is configured with a polygonal (e.g., hexagonal) cross-sectional geometry when viewed, for example, in a plane perpendicular to a centerline  148  of the respective cavity  144 . Referring to  FIG. 7B , the cavity centerline  148  may be arranged perpendicular to the bumper inner surface  138 /the bumper inner side  122 . Each cavity  144  of  FIG. 7B , for example, may extends longitudinally along its cavity centerline  148  between and to (or about) the bumper inner side  122  and the bumper outer side  124 . 
     In some embodiments, referring to  FIGS. 8A and 8B , the bumper  54  may be configured with or otherwise include foam; e.g., a foam body. Referring to  FIG. 8A , the foam may be configured as open cell foam  150  where its internal cavities  144  (e.g., pores) are interconnected. Referring to  FIG. 8B , the foam may alternatively be configured as closed cell foam  152  where its internal cavities  144  are discrete. 
     In some embodiments, referring to  FIG. 9 , the bumper  54  may be configured with or otherwise include a lattice structure  154 ; e.g., a lattice structure body. This lattice structure  154  may include one or more repeated cells, where each cell may include a plurality (e.g., a pattern) of interconnected elements  156 ; e.g., columns. 
     Referring to  FIG. 10 , the structure/configuration of the bumper  54  may be uniform axially across an axial length of the bumper  54  between and to the bumper ends  118  and  120  (see  FIG. 1 ). The structure/configuration of the bumper  54  may be uniform circumferentially about (e.g., completely around) the rotational axis  28 . The structure/configuration of the bumper  54  may also be uniform radially across the (e.g., radial) height  142  (see  FIG. 6A ) of the bumper  54  between and to the bumper sides  122  and  124 . Such an arrangement may provide the bumper  54  with a uniform damping characteristic. In other embodiments however, referring to  FIGS. 11 and 12 , the structure/configuration of the bumper  54  may be non-uniform to tailor the bumper  54  with a progressive stiffness characteristic and/or a progressive damping characteristic. 
     Referring to  FIG. 11 , an inner portion  158 A (e.g., radial zone) of the bumper  54  may be configured with a different stiffness characteristic and/or a different damping characteristic than an outer portion  158 B (e.g., radial zone) of the bumper  54 . The bumper inner portion  158 A is configured to deform (e.g., crush) when subject to an inner portion load. The bumper outer portion  158 B is configured to deform (e.g., crush) when subject to an outer portion load, where the outer portion load is different (e.g., greater or less) than the inner portion load. The bumper inner portion  158 A, for example, may be configured with an inner portion porosity and an inner portion density. The bumper outer portion  158 B may be configured with an outer portion porosity and an outer portion density, where the outer portion porosity is different (e.g., greater or less) than the inner portion porosity and the outer portion density is different (e.g., less or greater) than the inner portion density. For example, the bumper inner portion  158 A may be provided with an inner portion number of the internal cavities  144 , where each of those internal cavities  144  has an inner portion dimension (e.g., diameter, length, etc.). The bumper outer portion  158 B may be provided with an outer portion number of the internal cavities  144 , where each of those internal cavities  144  has an outer portion dimension (e.g., diameter, length, etc.). The inner portion number may be different (e.g., greater or less) than or equal to the outer portion number. The inner portion dimension may be different (e.g., greater or less) than or equal to the outer portion dimension. 
     For ease of illustration, the bumper inner portion  158 A of  FIG. 11  is shown with a greater density than the bumper outer portion  158 B. However, in other embodiments, the bumper outer portion  158 B may have a greater density than the bumper inner portion  158 A. 
     The bumper  54  is described above as including two (the inner and outer) portions  158 A and  158 B for tuning the stiffness characteristic and/or the damping characteristic. However, the bumper  54  may include more than two bumper portions; e.g., radial zones. For example, referring to  FIG. 12 , the bumper  54  may also include an intermediate portion  158 C radially between the bumper inner portion  158 A and the bumper outer portion  158 B. Each of these bumper portions  158 A-C (generally referred to as “ 158 ”) may be configured with a unique structure. Each of the bumper portions  158 , for example, may be configured to deform (e.g., crush) when subject to a different load. Alternatively, some of the bumper portions  158  (e.g.,  158 A and  158 B), but not all of the bumper portions  158  (e.g.,  158 C) for example, may be configured with a common structure. Any two of the bumper portions  158 , for example, may be configured to deform (e.g., crush) when subject to a first load whereas the remaining bumper portion  158  may be configured to deform (e.g., crush) when subject to a different (e.g., larger or small) second load. 
     In some embodiments, referring to  FIG. 13 , the bumper  54  may be further tailored by at least partially or completely filling one or more of the internal cavities  144  with filler material  160 . The cavities  144  in the bumper inner portion  158 A of  FIG. 13 , for example, are filled with the filler material  160 , whereas the cavities  144  in the bumper outer portion  158 B are empty. Of course, in other embodiments, the cavities  144  in the bumper outer portion  158 B may be filled with the filler material  160 , and the cavities  144  in the bumper inner portion  158 A may be empty (or partially or completely filled with the same filler material  160  or a different filler material). Examples of the filler material  160  include, but are not limited to, a polymer material and a potting material. 
     For ease of illustration, the bumpers  54  of  FIGS. 11-13  are shown with honeycomb cores. However, the foregoing teachings may also be applied to bumpers  54  with other configurations. For example, the porosity, the density, the number of internal cavities  144 , the dimensions of the internal cavities  144  and/or whether or not the internal cavities  144  are filled or empty may be tailored for the foam  150 ,  152  or the lattice structure  154 . Furthermore, it is also contemplated that the different portions  158  of the bumper  54  may be tailored with different internal structures. For example, one of the bumper portions  158  may have a honeycomb configuration whereas another one of the bumper portions  158  may have a foam configuration, etc. The present disclosure therefore is not limited to the foregoing exemplary bumper configurations. 
       FIG. 14  illustrates an example of the turbine engine with which the turbine engine assembly  20  may be configured. This turbine engine is configured as a turbofan gas turbine engine  162 . This turbine engine  162  of  FIG. 14  extends along the rotational axis  28  between an upstream airflow inlet  164  and a downstream airflow exhaust  166 . The turbine engine  162  includes a fan section  168 , a compressor section  169 , a combustor section  170  and a turbine section  171 . 
     The fan section  168  includes a fan rotor  174 . The compressor section  169  includes a compressor rotor  175 . The turbine section  171  includes a high pressure turbine (HPT) rotor  176  and a low pressure turbine (LPT) rotor  177 , where the LPT rotor  177  is configured as a power turbine rotor. Each of these rotors  174 - 177  includes a plurality of rotor blades arranged circumferentially around and connected to one or more respective rotor disks. 
     The fan rotor  174  is connected to the LPT rotor  177  through a low speed shaft  178 , which provides a low speed rotating structure  22 A. The compressor rotor  175  is connected to the HPT rotor  176  through a high speed shaft  180 , which provides a high speed rotating structure  22 B. The rotating structure  22  of  FIG. 1  may be configured as or otherwise included in either of the low speed rotating structure  22 A or the high speed rotating structure  22 B, and the shaft  30  may be configured as or otherwise included in the respective shaft  178 ,  180 . 
     During operation, air enters the turbine engine  162  through the airflow inlet  164 . This air is directed through the fan section  168  and into a core flowpath  182  (e.g., the flowpath  116  of  FIG. 1 ) and a bypass flowpath  184 . The core flowpath  182  extends sequentially through the engine sections  169 - 171 ; e.g., an engine core. The air within the core flowpath  182  may be referred to as “core air”. The bypass flowpath  184  extends through a bypass duct, which bypasses the engine core. The air within the bypass flowpath  184  may be referred to as “bypass air”. 
     The core air is compressed by the compressor rotor  175  and directed into a combustion chamber  186  of a combustor  188  in the combustor section  170 . Fuel is injected into the combustion chamber  186  and mixed with the compressed core air to provide a fuel-air mixture. This fuel-air mixture is ignited and combustion products thereof flow through and sequentially cause the HPT rotor  176  and the LPT rotor  177  to rotate. The rotation of the HPT rotor  176  drives rotation of the compressor rotor  175  and, thus, compression of air received from an inlet into the core flowpath  182 . The rotation of the LPT rotor  177  drives rotation of the fan rotor  174 , which propels bypass air through and out of the bypass flowpath  184 . The propulsion of the bypass air may account for a significant portion (e.g., a majority) of thrust generated by the turbine engine  162 . 
     The turbine engine assembly  20  and/or its bumper  54  may be included in various turbine engines other than the ones described above. The turbine engine assembly  20  and/or its bumper  54 , for example, may be included in a geared turbine engine where a gear train connects one or more shafts to one or more rotors in a fan section, a compressor section and/or any other engine section. Alternatively, the turbine engine assembly  20  and/or its bumper  54  may be included in a turbine engine configured without a gear train; e.g., a direct drive turbine engine. The turbine engine assembly  20  and/or its bumper  54  may be included in a geared or non-geared turbine engine configured with a single spool, with two spools (e.g., see  FIG. 14 ), or with more than two spools. The turbine engine may be configured as a turbofan engine, a turbojet engine, a turboprop engine, a turboshaft engine, a propfan engine, a pusher fan engine, an auxiliary power unit (APU) or any other type of turbine engine. The present disclosure therefore is not limited to any particular types or configurations of turbine engines. In addition, while the turbine engine is described above for use in an aircraft application, the present disclosure is not limited to such aircraft applications. For example, the turbine engine may alternatively be configured as an industrial gas turbine engine, for example, for a land based power plant. 
     While various embodiments of the present disclosure have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the disclosure. For example, the present disclosure as described herein includes several aspects and embodiments that include particular features. Although these features may be described individually, it is within the scope of the present disclosure that some or all of these features may be combined with any one of the aspects and remain within the scope of the disclosure. Accordingly, the present disclosure is not to be restricted except in light of the attached claims and their equivalents.