Regression analysis method for superalloy stress relaxation process

Based on the linear process regression analysis theory, a regression analysis method for superalloy stress relaxation process was put forward. Then the residual stress regression equation and one-sided lower confidence limit curve with high confidence level and reliability were given. By this method, the stress relaxation process can be analyzed as an integration and the lengthwise information of the residual stresses at different test times is applied, therefore the presented method not only has higher precision but also provides reasonable estimates for small sample sizes. Furthermore, the proposed method can avoid distortion of the relaxation curve in the traditional method especially when the sample size is very small.