Robust prediction and optimization of surface roughness and kerf taper in AWJM of titanium mesh basalt carbon hybrid composites

This study investigates abrasive water jet machining (AWJM) of a hybrid titanium mesh/basalt fiber/carbon fiber stacked composite, focusing on machining behavior at dissimilar metal-fiber interfaces. Unlike homogeneous composites, the laminate shows non-uniform erosion due to combined ductile metallic and brittle polymeric phases, limiting conventional machining models. A design of experiments approach integrated with response surface methodology (RSM) was used to evaluate the effects of abrasive jet pressure, traverse speed, abrasive flow rate, and stand-off distance on surface roughness and kerf angle. Abrasive jet pressure is identified as the dominant factor due to its influence on jet energy distribution and interlayer erosion stability. The study highlights how material heterogeneity and interfacial interactions govern erosion mechanisms in hybrid stacked composites, an area underexplored in existing AWJM literature focused mainly on uniform materials. The developed RSM models show high predictive accuracy (R² > 0.99) within the investigated experimental design space, although their applicability beyond the studied parameter range requires further validation. Results confirm that AWJM can machine complex hybrid laminates without thermal damage, minimizing machining defects and post-processing needs. Overall, the work extends AWJM understanding from conventional composites to multi-material systems, improving insight into erosion behavior and predictive modeling of hybrid laminates.