Recent content by feajob

Hi Guys, I appreciate your replies. I'd like to provide additional information: The original material drawing called for PH13-8Mo stainless steel, solution treated according to AMS 5629, with a subsequent heat treatment to condition H1000 (205 KSI minimum UTS) per AMS 2759/3. We received...

Hello Everyone, I'm reaching out for your input. My background is in fatigue life assessments, not materials engineering, so I'd value your thoughts on these statements: Risks Associated with Machining Pre-Hardened PH13-8Mo: Increased Residual Stresses: Machining hardened material generates...

Hello, We need to design a fuse pin for a main landing gear. The goal is to achieve controlled shear failure to protect the aircraft. Our focus is on achieving a predictable failure in shear mode rather than tension or bending, as shear failure provides more controlled separation. To control the...

Based on the e-mail reply that I received from Battel Columbus "The equation included with each MMPDS S/N curve is the typical regression line, 50% survival. And, the 97.7% survival probability can be computed, by subtracting 2.0 x the standard error of the estimate from the typical line."...

Hi, I would like to know what is the Certainty of Survival for the S-N (stress-life) Curves presented in MMPDS? Thanks, A.

Perfect. Thank you.

Yes, I agree with you. I also noticed that there are no S/N curves for 7050-T7451 in MMPDS-15. I sent an email about these S/N Curves to Battelle Memorial Institute, and I didn't receive any answer until now.

Thank you for your reply. I think that 800 cpm (cylces per minute) is equivalent to 800 /60 = 13.3 Hz (cycles per second) versus 20 Hz (not 20,000 Hz).

Figure 3.7.5.2.8(b): Product Form = 4.25 to 8.50 inches thick Specimen Details: Unnotched 0.25 inch diameter Surface Condition: Polished, final surface finish unspecified Test Parameters: Loading - Axial, Frequency - 20 Hz, Temperature - RT, Environment - Air No. of Heat/Lots: Unspecified Sample...

Figure 3.7.5.2.8(b): Product Form = 4.25 to 8.50 inches thick Specimen Details: Unnotched 0.25 inch diameter Surface Condition: Polished, final surface finish unspecified Test Parameters: Loading - Axial, Frequency - 20 Hz, Temperature - RT, Environment - Air No. of Heat/Lots: Unspecified...

Hi Guys, I recently noticed that there is significant difference between the predicted life with S/N curves shown in Figures 3.7.5.2.8(b)and 3.7.5.2.8(e) in MMPDS-09. Both of them are "for unnotched 7050-T7451 plate, long transverse direction, t/4 specimen locations". The second one is giving...

Hi Guys, I recently noticed that there is significant difference between the predicted life with S/N curves shown in Figures 3.7.5.2.8(b)and 3.7.5.2.8(e) in MMPDS-09. Both of them are "for unnotched 7050-T7451 plate, long transverse direction, t/4 specimen locations". The second one is giving...

Hi Guys, I noticed that on page A-7 of MMPDS-15, it is written that "S/N Curves are for a 50 percent probability of survival. We usually assume conservatively few fatigue penalization factors (such as anodizing + shot-peening, surface finish, ...). But, I would like to know if you apply another...

O.K., thanks. For 17-7PH the recommended range is 45% (not 35%).

Thanks again for your reply. We use the Tensile Strength shown in Table 4A of AMS 5678F (SAE). In this document, it is not mention Ultimate or Limit. But, for a wire diameter of (4.57mm to 5.26mm), manufactured from 17-7PH, CH900, the Tensile Strength are Min. 1738 MPa Max. 1944 MPa I think...