A High Accuracy Incremental Hole‐Drilling Method for Residual Stress Measurement and Analysis of a New Type M55J ‐ CF / CE Composite Laminates

ABSTRACT Accurate measurement and analysis of the residual stress (RS) magnitude and distribution in fiber‐reinforced composite laminates are critically important. In the present study, a new type M55J carbon fiber cyanate ester (M55J‐CF/CE) composite laminate was prepared, featuring ply angles of [0° ₄ ] _s and [0°/45°/−45°/90°] _s , respectively. Based on the incremental hole‐drilling (IHD) theory and FE calibration matrix method, and combined with a self‐built CNC‐IHD strain collection device. The gradient measure strain (MS) and RS distribution were obtained under different incremental step depths, laying angles, specimen thicknesses, and applied loads. The morphology and micro‐size of the drilled holes, verified through SEM, exhibit high quality and accuracy, and no phenomena beyond the single thickness range were observed. The research results showed that the 20 μm/step had high collection accuracy compared with others. The range of strain release decreased by about 40%, when the specimen thickness increased from 1.5 to 3 mm. And the RS distribution caused by different layering angles shows “linear enlargement type” and “angular fluctuation type,” respectively. It reveals the mechanism by which the dominant direction of fibers in different layers promotes the corresponding release of RS distribution. The aforementioned research provides methodological support for RS measurement and analysis of similar composite laminates.