CYCLIC SHAKEDOWN LIMIT TESTING AND ANALYSIS OF THE INFLUENCE OF YIELD STRENGTH PARAMETERS ON SQUARE PLATES WITH A CENTRAL CIRCULAR HOLE

Under cyclic loading, structures can reach a stable state through limited plastic deformation and redistribution of residual stress. Existing stability analyses usually use the yield strength obtained from uniaxial tensile tests as a material parameter, but its applicability for predicting the stability limit of structures under cyclic loading still needs further verification. This paper first obtains the monotonic yield strength and cyclic yield strength of 316L stainless steel through uniaxial tensile tests and strain-controlled cyclic loading tests; second, performing hierarchical multiple cyclic loading tests on square plates with a central circular hole made of the same material, the stability limit load range of the structure is identified by combining key factors such as strain evolution in the dangerous area around the hole and the average strain rate; finally, based on an ideal elastic-plastic finite element numerical analysis model, the effects of different yield strength parameters on predicting the stability limit are compared. The results show that the cyclic yield strength of the 316L material is lower than the monotonic yield strength, and the stability limit load identified by structural testing is 151.85 ~ 162.96 MPa. When using the monotonic yield strength, the predicted values are overestimated by 12.30% ~ 20.51%; when using the cyclic yield strength, the prediction deviation is only 1.86% ~ 9.31%. Clearly, the choice of yield strength parameters has a significant impact on the predicted stability limit of perforated plates, and cyclic yield strength is more suitable for stability analysis.