Variation Simulation and Diagnosis Model of Compliant Block Assembly Considering Welding Deformation

Abstract

This article proposes a variation simulation and diagnosis model for ship block assembly processes considering the effects of welding distortion. The welding process and the deformation pattern affecting the final shape of a block assembly are diagnosed. Prior studies on welding distortion mainly focused on mitigation methodologies. In this research, welding distortion is regarded as the main cause of geometric variation in parts. In addition, how geometric variations are accumulated throughout multiple assembly processes is mathematically modeled. The variation simulation model is based on a state space equation, where variations of previous stages are propagated to the current stage. The diagnosis model predicts the quantitative effect of each variation source on the final assembly's geometrical variation, based on a normal equation and designated component analysis. The proposed model is simulated with FEM (Dassault Systemes Americas Corp., Waltham, MA) and MATLAB (Mathworks (https://www.mathworks.com/), Massachusetts, United States) replicating a realistic block assembly process for validation. The model can effectively simulate the propagation of welding distortion and quantitatively diagnose variation patterns and welding processes.