PSI - Issue 60

Sreerag M N et al. / Procedia Structural Integrity 60 (2024) 20–35 Sreerag M N/ Structural Integrity Procedia 00 (2023) 000 – 000

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Table 10: Comparison of FE computed failure pressure for different cases

Failure pressure

Cyl. Shell

L/S joint

C/S joint

T-joint

unflawed

With 5x2 mm defect

PM PM PM PM PM PM

R0 R0 R0 R0

R0 R0

R0 R1 R1 R1 R1 R1 R1

91.91 91.83 91.82 91.90 90.99 89.52

80.36 80.36 80.36 80.36 79.86 78.93 78.40

Ro/Local R1 R0/Local R2 R0/Local R2 R0/Local R2

R0/Local R1 R0/Local R2

R1

R1

R1

88.8

7. Salvage of motor case hardware with weld repair deviation 8.2 m long and Ø3.2 m cylindrical hardware is used in the SRB of LVM3. 2 nd weld repair (which is considered as deviation as the design accounts for only 1 st repair) was carried out at following two locations in one of the Cirseam welds of this cylinder. Figure-7 shows the measured profile error (error w.r.to a uniform circular diameter) in the repair zones.  R2 repair at RT spot 17+242 to 17+26  R2 repair at RT spot 17+89 to 17+105

Fig 7: Profile error at outer surface for cirseam weld After the weld defect repair process, the motor case hardware was subjected to proof pressure test at 1.18 times operating pressure of the rocket motor to evaluate the structural integrity and screen out any defects in the hardware. For this the hardware was filled with hydraulic oil and pressurized to 66ksc. Both ends of the hardware was closed with suitable end closures. During the proof pressure test at 66 ksc, two locations (i.e. at RT 17+242 & RT 17+74) in cirseam weld were strain gauged both on the inner and outer surface. Fig 8 & 9 shows the strain gauge pattern followed for the test.