NONLINEAR SOLUTIONS LLC, Failure Analysis

Problem 1: The hypervelocity Light Gas Gun projectile failed, where are the design weak points?

Solution:

Created a finite element model of the Hypervelocity Light Gas Gun Projectile and applied loading environment:

Light Gas Gun Model was developed from drawings
High acceleration body force loading was applied
Analysis determined the high-stress was at a thickness transition region shown as a red contour in Figure 1
Design changes were recommended to decrease the rapid change in thickness to reduce stress and eliminate/reduce failure risk

Problem 2: There is an out of tolerance 0.060 inch gap between the Solid Rocket Booster (SRB) Lead Coupler and Insert will the bolt threads fail?

Solution:

Created a finite element model of the SRB Lead Coupler and Insert to determine the shear force on the threads:

SRB Lead Coupler and Insert model with 0.060 inch gap were developed from drawings
Pressure time-history was applied to the coupler
Calculated shear force on the bolt threads would not cause a failure

Figure 1. Hypervelocity Light Gas Gun Projectile failure analysis

Figure 2. SRB 0.060 inch gap failure analysis

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Harvest, AL 35749

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mike.howell@nonlinear-solution.com