Estimation Method of Singular Stress Field at Bonded Edge by Inverse Analysis of Deformed Shape Data

This study has developed a novel method to estimate the singular stress field at the bonded edge by applying an inverse analysis on the deformed shape of the adherend, without explicitly considering microscopic behaviors of the bonded interface.The mathematical model used in the inverse analysis does not need to be a model of the entire adherend, and can be a partial model of the bonded member based on the free body diagram concept.In the inverse analysis, the Tikhonov regularization is applied to reduce the influence of displacement measurement errors on the estimated values.In order to verify the basic validity of the estimation method, peel tests were performed in numerical simulations and actual tests, and the singular stress field at the bonded edge was estimated by the estimation method.In the verification, the regularization parameter selection in the inverse analysis was discussed based on the test results.The numerical simulations show that both the stress intensity factor and the stress singularity index remained almost constant between a certain range of the regularization parameters, and were close to the correct values.Then, the inverse analysis results agree with the correct values.The actual test results show good agreement with each other, and are close to the direct analysis results.These results indicate that the proposed estimation method is effective for estimating the singular stress field at the bonded edge.