Wave relieving geometric features in structural members that are radially expandable into workpieces

Abstract

A bushing with wave relieving geometric features includes a unique geometric end feature such as a countersink or arcuate surface, which creates a pocket, volume, and/or reservoir, to receive an amount of material that is extruded in a longitudinal direction during radial expansion of the bushing. At the mandrel exit side of the bushing, the extruded material may be accumulated from a propagating wave of material preceding a radial-expansion mandrel. At the mandrel entry side of the bushing, the extruded material may be caused by the radial force of the expansion mandrel near the unrestrained end surface at the entry side of the bushing. The unique geometric end features of the bushing may also include a high portion on the end surface of the bushing to direct the fastener clamp-up loads through the radial flange of the bushing and into the workpiece.

1 . A structural member installable in an opening of a workpiece by radial expansion via an expansion mandrel, the structural member comprising: 
 a tubular body having a first end, a second end opposite the first end, a peripheral outer surface disposed between the first and the second ends, the tubular body having a first face at the first end, a second face at the second end, and an inner surface that extends between the first and the second ends to form a longitudinally-extending passage therebetween, wherein in a pre-installed state the tubular body has a first recess formed on the first face about the longitudinally-extending passage and adjacent thereto, the first recess having a volume sized to accommodate a first amount of upset material that will be formed by passage of the expansion mandrel through the longitudinally-extending passage to install the structural member in the opening of the workpiece.    
   
   
       2 . The structural member of  claim 1  wherein in the pre-installed state the tubular body has a second recess formed on the second face about the longitudinally-extending passage and adjacent thereto, the second recess having a volume sized to accommodate a second amount of upset material that will be formed by passage of the expansion mandrel through the longitudinally-extending passage to install the structural member in the opening of the workpiece.  
   
   
       3 . The structural member of  claim 2  wherein the volume of one of the first or the second recesses is sized to accommodate an entrance amount of upset material formed by entrance of the expansion mandrel into the opening of the workpiece and wherein the volume of the other one of the first or the second recesses is sized to accommodate an exit amount of upset material formed by exit of the expansion mandrel from the opening of the workpiece, wherein the entrance amount of upset material is not equal to the exit amount of upset material.  
   
   
       4 . The structural member of  claim 1 , further comprising: 
 a radial flange radially extending from the peripheral outer surface of the tubular body, the radial flange proximate one of the first end or the second end thereof.    
   
   
       5 . The structural member of  claim 1  wherein the longitudinally-extending passage is concentric with the peripheral outer surface.  
   
   
       6 . The structural member of  claim 5  wherein a cross-section of the peripheral outer surface taken perpendicularly to a longitudinal axis of the longitudinally-extending passage is approximately circular.  
   
   
       7 . The structural member of  claim 6  wherein a cross-section of the longitudinally-extending passage taken perpendicularly to the longitudinal axis of the longitudinally-extending passage is approximately circular.  
   
   
       8 . The structural member of  claim 1  wherein the structural member comprises at least one selected from the group consisting of a liner, a bearing, a fastener, a shank, and a conduit.  
   
   
       9 . The structural member of  claim 1  wherein the structural member is a rivet, and further comprises: 
 a radial flange sized to engage at least a portion of a nut cage.    
   
   
       10 . A structural member installation, comprising: 
 a workpiece having an opening formed therein; and    a tubular body having a first end, a second end opposite the first end, a peripheral outer surface disposed between the first and the second ends, the tubular body having a first face at the first end, a second face at the second end, and an inner surface that extends between the first and the second ends to form a longitudinally-extending passage therebetween, wherein, in an installed state, the peripheral outer surface deformingly engages the workpiece to form an interference fit therewith and a first amount of upset material formed by passage of an expansion mandrel through the longitudinally-extending passage to install the structural member in the opening of the workpiece is accommodated by a first recess adjacent to and surrounding the longitudinally-extending passage such that the first amount of upset material does not extend outwardly beyond the first face of the tubular body or inwardly from the inner surface into the longitudinally-extending passage.    
   
   
       11 . The structural member installation of  claim 10  wherein, in the installed state, a second amount of upset material that will be formed by passage of the expansion mandrel through the longitudinally-extending passage to install the structural member in the opening of the workpiece is accommodated by a second recess adjacent to and surrounding the longitudinally-extending passage such that the second amount of upset material does not extend outwardly from the second face of the tubular body or inwardly from the inner surface into the longitudinally-extending passage.  
   
   
       12 . The structural member installation of  claim 10  wherein the first amount of upset material is not equal to the second amount of upset material.  
   
   
       13 . The structural member installation of  claim 10 , further comprising: 
 a radial flange radially extending from the peripheral outer surface of the tubular body, the flange proximate one of the first end or the second end.    
   
   
       14 . The structural member installation of  claim 10  wherein the longitudinally-extending passage is concentric with the peripheral outer surface, a cross-section of the peripheral outer surface taken perpendicularly to a longitudinal axis of the longitudinally-extending passage is approximately circular, and a cross-section of the longitudinally-extending passage taken perpendicularly to the longitudinal axis of the longitudinally-extending passage is approximately circular.  
   
   
       15 . A method of radially expanding a structural member into a workpiece, the method comprising: 
 positioning an expansion mandrel at an entrance of a longitudinally-extending passage extending through the structural member, the structural member having a first end, a second end opposite the first end, a peripheral outer surface disposed between the first and the second ends, the structural member further having a first face at the first end, a second face at the second end, and an inner surface that extends between the first and the second ends to form the longitudinally-extending passage therebetween;    passing the expansion mandrel through the longitudinally-extending passage to radially expand at least a portion of the structural member into the workpiece; and    longitudinally displacing some of the material of the structural member into at least one recess of the structural member, the recess having a volume sized to accommodated a first amount of upset material, wherein the volume of the recess is sufficient to receive the displaced material without permitting any of the displaced material to extend beyond a desired distance relative to the respective face.    
   
   
       16 . The method of  claim 15  wherein longitudinally displacing some of the material of the structural member into the at least one recess includes displacing an amount of material into the recess in the form of a pocket defined by an arcuate surface.  
   
   
       17 . The method of  claim 15  wherein longitudinally displacing some of the material of the structural member into the at least one recess includes moving a wave of the material ahead of the expansion mandrel passing through the longitudinally-extending passage.  
   
   
       18 . The method of  claim 15  wherein longitudinally displacing some of the material of the structural member into the at least one recess includes permanently deforming an amount of the material in a region proximate to where the expansion mandrel enters the structural member.  
   
   
       19 . A method of manufacturing a structural member to be secured into an opening of a workpiece, the method comprising: 
 forming an outer surface and an inner surface, the outer surface radially offset from the inner surface to form a wall of the structural member;    forming a first end and a second end opposite the first end;    forming a first face at the first end and a second face at the second end, the inner surface extending between the first and the second ends to form a longitudinally-extending passage therebetween; and    forming a recess into at least one of either the first face or the second face, wherein the recess defines a volume sized to accommodated a first amount of upset material expected when an expansion mandrel is passed through the longitudinally-extending passage during a radial expansion process to secure the structural member into the opening of the workpiece.    
   
   
       20 . The method of  claim 19  wherein forming the recess includes machining the first face so as to form the recess, the recess located adjacent the longitudinally-extending passage.  
   
   
       21 . The method of  claim 19  wherein forming the recess includes machining the second face so as to form the recess, the recess located adjacent the longitudinally-extending passage.  
   
   
       22 . The method of  claim 19  wherein forming the first end includes forming a radial flange.  
   
   
       23 . The method of  claim 22  wherein forming the recess includes machining in at least a portion of the radial flange to form at least a portion of the recess.  
   
   
       24 . The method of  claim 19  wherein forming the recess includes forming an arcuate surface on at least one of either the first face or the second face of the structural member.  
   
   
       25 . The method of  claim 19  wherein forming the recess includes forming a countersink surface on at least one of either the first face or the second face of the structural member.