Damage created by abrasive waterjet and conventional drilling in open-hole and assembled 3D interlock woven carbon fiber-reinforced plastic composites examined by fatigue testing and linear regression analysis

• Assessing the influence of secondary machining processes on the fatigue behavior. • Fatigue damage description by thermal imaging and acoustic emission. • Modelling of the minimal strain for both open-hole and assembled samples. • Prediction of the model parameters with hole characteristics. With the advent of 3D woven composites, delamination is no longer a major concern when drilling holes in composite structures, but the effects of the other hole characteristics must be assessed. Here, the abrasive waterjet is compared with a conventional cutting tool to reveal their damage characteristics and assess their influence on the mechanical properties of the composites. Tensile failure is observed in open-hole samples and shear failure is preceded by bearing damage in assembled samples. The magnitude of the damage is estimated using acoustic emission and thermal imaging. The results show that roughness plays an important role in damage initiation for both open-hole and assembled loading. Thus, the proposed model helps identify the differences in the degradation of mechanical properties between the two drilling methods.