hi all
please help me to find solution

1) in caesar material database eg:carbon steel
the yield stress is decreasing(100 deg onward)while temperature increasing but allowable stress is constant till 343 deg(inline with Code) .As we know the allowable stress is 2/3 of yield stress.then why allowable stress not changing with yield stress change

2)i need to do analyse bunch of small bore separately which connected to header.for boundary condition i considered displacement of header at each connecting point and SIF which i calculated from Caesar SIF scratch pad here im getting two SIF one for header and one for branch ,which one i should considered for analysis