Sensitivity analysis of stress/strain evolution on removal thickness in machining laser cladded workpiece with a novel FEM method

During subsequent machining of laser cladded workpiece, the stress transferred in depth direction is different from the conventional cast workpiece due to the geometrical discontinuity, resulting in the stress difference and strain discontinuity at the interface between the cladding layer and substrate. Distinguishing from the traditional finite element method model, this paper establishes a model with an inclined interface to investigate the thickness ratio, i.e., the ratio of the removal thickness in subsequent machining to cladding thickness on the machining-induced stress and strain. The results show that the maximum thickness ratio is 0.352 when the removal thickness is 0.1 mm. The change in interfacial shear stress energy dissipation due to interfacial inclination makes this result 22.8% lower than a traditional model with a horizontal interface. With the help of the presented model, the effect of removal thickness on machining-induced stress and strain evolution was investigated. The results show that an increase in the removal thickness will lead to an increase in machining-induced stress and strain. The stress difference and strain increment at the interface increase proportionally with the removal thickness, implying that variations in removal thickness will have a consequential impact on the maximum thickness ratio. Thus, the interaction of material removal thickness and thickness ratio on PEEQ increment at the interface was further analyzed. The response surface results indicate that an increase in the removal thickness leads to a corresponding increase in the maximum thickness ratio, albeit with a minor degree of influence. Therefore, the challenge of fixing the maximum thickness ratio in actual machining due to multi-step processes can be resolved through micro-adjustments. Simultaneously, in engineering applications, workpiece surface defects exhibit varying depths and require different removal amounts after cladding. This study provides further theoretical guidance for repairing and remanufacturing surface defects with diverse depths.