Abstract:
This paper presents an inverse method for calculating the thermal residual
stresses in welded specimens via measured fatigue crack growth rates. Firstly,
fracture-mechanics superposition law has been used to extract the stress
intensity factor due to residual stress contribution from measured crack growth
rate. Secondly, a so-called B matrix has been established by performing finite
element analysis. Residual stress distribution is then determined by solving
linear algebraic equations relating the B matrix and residual stress intensity
factors obtained from crack growth test data. The inverse method has been
validated by a well-established residual stress distribution and corresponding
stress intensity factor, and then applied to an M(T) sample in 2024-T3 alloy
with a longitudinal weld. Agreement with the measured residual stresses is
reasonably good and reasons for certain differences between the calculated and
measured are discussed.
