Torque Collar Concept

C Neumeyer 7/14/3

The torque collar concept shown in the figures below provides the
following functions....

1)  Transmits limited vertical load to the collar via 12 shoulder
    bolt/Belleville washer attachment between collar and hub disk

2)  Decouples thermal expansion of the collar from the hub disk via
    slotted holes for the shoulder bolts in 1)

3)  Transmits torque from the inner leg bundle to the hub disks via the
    shoulder bolts in 1)

4)  Accommodates position error in the wet lay-up via alignment rings
    which attach by bolted connection to the hub disks. The guide shoes
    interact directly with the shoulder bolts in 1)

5)  Provides compression to the wet lay-up to enhance shear allowable

![](media/image1.jpeg){width="5.992361111111111in"
height="4.179166666666666in"}

> ![](media/image2.jpeg){width="5.997916666666667in"
> height="3.884027777777778in"}

The following calculation shows the sizing of the Belleville washer
spring constant and the wet lay-up compression such that the safety
factor on the wet lay-up shear is equal to 2.0.

  ------------------------------------------ ---------------- -----------
  Total Vertical Load                        249325           lbs

  Net Belleville Spring Constant             3.91E+06         lb/in

  Fraction of Vertical Load to Collar        0.10              

  ∆Lthermal                                  0.007            in

  Belleville Deflection Max                  0.018            in

  Force to Deflect Belleville Max            6000             lb

  K (One Belleville)                         333333           lb/in

  \# Belleville                              12                

  Collar Height                              3.25             in

  Inner Leg Groundwall Outer Radius          3.96             in

  Circumference                              24.88            in

  Area                                       80.86            in\^2

  Torque in Collar                           42000            N-m

                                             30976            ft-lbs

                                             371717           in-lbs

  f Torsion to Collar                        1.0               

  Torsional Force in Collar                  93868            lbs

  Vertical Load in Collar                    24554            lbs

  Thermal Load to Collar                     22879            lbs

  Combined Load in Collar                    105171           lbs

  Collar Safety Factor                       2.0               

  Wet Lay-up Shear Strength                  1700             psi

  Compression for Safety Factor              3004             psi

  Shear Strength w/compression               2601             psi
  ------------------------------------------ ---------------- -----------

> Collar bolting scheme must accommodate both the radial thermal
> expansion of the copper inner leg bundle and the need to compress the
> wet lay-up.

  ---------------------------------------------------- ----------- -------
  Cu Coeff of Expansion                                1.69E-05    per
                                                                   degC

  Tinit                                                10          degC

  R Cu at Tinit                                        3.874       in

  Tsoft                                                29          degC

  ∆R Cu SOFT                                           1.24E-03    in

  Teoft                                                66          degC

  ∆R Cu EOFT                                           3.67E-03    in

  Teop                                                 95          degC

  ∆R Cu EOP                                            5.57E-03    in

  Wet Lay-up Elasticity                                1.00E+06    psi

  Wet Lay-up Thickness                                 0.250       in

  Wet Lay-up K                                         3.23E+08    lb/in

  Collar Elasticity                                    2.90E+07    psi

  Collar Thickness                                     0.500       in

  Collar K for Circumferential Displacement            1.68E+06    lb/in

  #Collar Bolts                                        4           

  #Collar Gaps                                         3            

  Bolt Dia                                             0.5         in

  Pitch Dia                                            0.449       in

  Threads/inch                                         13           

  Bolt Tensile Stress Area                             0.14        in\^2

  Bolt Elasticity                                      2.90E+07    psi

  Bolt Length                                          1.25        in

  K per Bolt                                           3.29E+06    lb/in

  Net Bolt K for Circumferential Displacement          4.39E+06    lb/in

  Net Collar K for Circumferential Displacement        1.22E+06    lb/in

  Net Collar K for Radial Displacement                 7.64E+06    lb/in

  Net K                                                7.46E+06    lb/in

  Thermal Force SOFT                                   9284        lb

  Thermal Compression SOFT                             115         psi

  Thermal Hoop Tension SOFT                            1524        lb

  Thermal Force EOFT                                   27362       lb

  Thermal Compression EOFT                             338         psi

  Thermal Hoop Tension EOFT                            4493        lb

  Thermal Force EOP                                    41532       lb

  Thermal Compression EOP                              514         psi

  Thermal Hoop Tension EOP                             6819        lb

  Collar Hoop Tension for Compression                  38666.71    lbf

  SOFT Hoop Tension Deficit=Preload                    29383.05    lbf

  EOP Hoop Tension Maximum                             36202.13    lbf

  Collar Hoop Stress Maximum                           22278       psi

  Force/Bolt                                           9051        lbf

  Bolt Stress                                          63782       psi

  Bolt Safety Factor                                   1.5          

  Bolt Mat\'l Tensile Yield for Safety Factor          95673       psi
  ---------------------------------------------------- ----------- -------

The 12 1/2" diameter shoulder bolts must handle the vertical and thermal
loads and transmit the torque. They thread into the hub disk but bear
against the alignment ring.

  -------------------------------------------------- ------------ --------
  #Shoulder Bolts                                    12            

  Bolt Radial Location                               7.8265       in

  Torsional Force at Bolt Radius                     47495        lbs

  Shear Force/Bolt                                   3958         lbs

  Shoulder Bolt Dia                                  0.5          in

  Shoulder Bolt Depth                                0.75         in

  Bearing Area                                       0.375        in\^2

  Shear Area in Bolt                                 0.20         in\^2

  Shearing Yield                                     0            lbs

  Shearing Safety Factor                             2.0           

  Shear Allowable/Tensile Allowable                  0.50         

  Bolt Tensile Yield Strength for Safety Factor      80629        psi

  Bearing Stress Concentration Factor                2.3           

  Bearing Safety Factor                              2.00          

  Bearing Yield Strength for Safety Factor           48550        psi

  Tensile Force/Bolt                                 3953         lbf

  Male...                                                          

  Bolt Dia                                           0.5          in

  Pitch Dia                                          0.449        in

  Threads/inch                                       13            

  Bolt Tensile Stress Area                           0.14         in\^2

  Bolt Stress                                        27856        psi

  Bolt Safety Factor                                 1.5           

  Bolt Mat\'l Tensile Yield for Safety Factor        41784        psi

  Female...                                                        

  Shear Safety Factor                                2.0           

  Thread engagement length                           0.500        in

  Shear area                                         0.529        in\^2

  Shear Allowable/Tensile Allowable                  0.50          

  Tensile yield for Safety Factor                    29890        psi
  -------------------------------------------------- ------------ --------

The 12 5/8" diameter alignment ring attachment bolts must provide
sufficient force such that the friction between the ring and the collar
can react the torsional force.

  ------------------------------------------ ---------------- -----------
  Male....                                                     

  Bolt Diameter                              0.625            in

  Threads/inch                               11.000            

  Pitch Diameter                             0.589            in

  Tensile Area                               0.226            in\^2

  Bolting Radius                             7.827            in

  Torsional Load                             47495            lbf

  Friction Safety Factor                     2.0               

  Friction Capacity for Safety Factor        94989            lbf

  Friction Coefficient                       0.390             

  #Bolt                                      12                

  Axial load/bolt                            20297            lbf

  Tensile Safety Factor                      1.5               

  Tensile yield for Safety Factor            134712           psi

  Female...                                                    

  Shear Safety Factor                        2.0               

  Thread engagement length                   0.938            in

  Shear area                                 1.301            in\^2

  Shear Allowable/Tensile Allowable          0.50             psi

  Tensile yield for Safety Factor            62401            psi
  ------------------------------------------ ---------------- -----------