triumph406
Aerospace
- Oct 28, 2005
- 47
Using the classical model of a single edge corner crack (not the one with the user defined beta solution), a crack with the dimensions of A = C = 0.015625” is applied to a specimen with the dimensions of 4” width and 0.120” thickness.
A max stress of 41 ksi and stress ration of R = -1 is applied to the spectrum.
Applying the material model with the NASGROW equation, the analysis results show that with the material model for PH13-8 H1000 SS, fracture occurs at 167,630 cycles while with the material model for 15-5PH H900, fracture occurs at 311,675 cycles. Despite the greater fracture toughness of PH13-8 H1000, the greater life is achieved with 15-5PH H900.
I would have expected the 13-8 to have significantly more cycles to failure than with 15-5. I have always believed 13-8 to be a better material than 15-5 for fracture life, but using AFGROW shows that not to be the case. I wonder if I have always been mistaken in my belief in 13-8, or if there’s a problem with the material model in our AFGROW.
A max stress of 41 ksi and stress ration of R = -1 is applied to the spectrum.
Applying the material model with the NASGROW equation, the analysis results show that with the material model for PH13-8 H1000 SS, fracture occurs at 167,630 cycles while with the material model for 15-5PH H900, fracture occurs at 311,675 cycles. Despite the greater fracture toughness of PH13-8 H1000, the greater life is achieved with 15-5PH H900.
I would have expected the 13-8 to have significantly more cycles to failure than with 15-5. I have always believed 13-8 to be a better material than 15-5 for fracture life, but using AFGROW shows that not to be the case. I wonder if I have always been mistaken in my belief in 13-8, or if there’s a problem with the material model in our AFGROW.
