Digital twin-driven real-time suppression of delamination damage in CFRP drilling

Delamination damage should be avoided because it severely affects the quality of CFRP products. This paper proposes a digital twin (DT) driven method for real-time suppression of delamination damage to ensure the highest quality hole exit. The relationship between the increase in thrust caused by tool wear and CFRP delamination was analyzed through extensive drilling experiments. The evolving twin models were developed to integrate the virtual space of the drilling process. Once the cutting parameters and thrust signals were input into the twin, the Gaussian process regression and mathematical models predicted the current tool wear and thrust curve, respectively. The feedback results from the DT dynamically interact with the real drilling operation after the optimization function solves the current critical feed rate (CFR). A DT scheme was designed, and the performance of the deployed DT was tested through an online service panel. The results show that the DT has excellent real-time prediction capability within 100 hole-making cycles, with maximum errors of 4.1% and 4.2% for tool wear and thrust prediction at the exit, respectively. Compared to conventional drilling (CD), DT technology provides closed-loop feedback on the time-varying CFR for each hole, resulting in no delamination mode I and up to 48.4% suppression of delamination mode III. This research has achieved intelligent virtual-real linkage in the CFRP drilling process, providing important theoretical support for effectively suppressing delamination damage in the automated production process.