Measurement and analysis of residual stress of multilayer carbon fiber laminate based on incremental drilling method

In the automotive and aerospace industries, carbon fiber is widely used in structures such as chassis and wings due to its lightweight and excellent mechanical properties, and the residual stresses are crucial for product design. In this paper, six kinds of carbon fiber laminates with different layup directions are investigated by using the integral method, and the calibration coefficient matrix is numerically solved by using ABAQUS finite element software, and the effects of laminate direction and incremental step on the three-direction residual stresses are experimentally analyzed. The residual stresses in different oriented layers were predicted by classical lamination theory (CLT), and the longitudinal, transverse and in-plane shear stresses were compared by combining incremental drilling experiments with calibration factors. The results showed that the ply with [45/90/ - 45/0/45/90/ - 45/0] laminate had the best performance,the difference between theoretical and experimental values for sigma x was 0.421 MPa. The maximum tau xy measurement was 1.7103 MPa, with a maximum percentage error of 25.3%. The maximum difference for sigma y was 0.7306 MPa. These findings indicate that the method is more accurate in predicting the residual stresses in the first four layers of composite material. This provides important theoretical and experimental support for the optimal design of composites.