Service Life Extension and Failure Prevention of a Washing Machine Spider Arm Using Flexible Multibody Analysis

Abstract

In this study, a failure-based parametric design study was carried out to extend the service life of the spider arm component used in washing machines while exploring potential cost savings. Representative loading conditions were determined using a washing machine test setup operating at full capacity, and the resulting unbalanced mass data were employed in a Flexible Multibody Dynamics (FMBD) analysis. Modal analyses were performed for the drum and tub assemblies, and the corresponding flexible body representations were incorporated into the multibody model. Based on the analysis results, regions exhibiting high stress concentrations were identified as critical regions, and three geometric design parameters were defined on the spider arm to reduce stress levels in these areas. A three factor, two level parametric design study was conducted to evaluate the influence of these parameters within manufacturable limits. Among the tested configurations, the best performing tested design within the investigated design space achieved an approximately 15% reduction in maximum stress, corresponding to an approximately 1.8 times increase in fatigue life. The potential economic implications of the observed fatigue life improvement were also examined using a scenario based cost analysis. Based on company specific production assumptions, the analysis suggests potential annual cost savings of €9.3–12.0 million under conservative assumptions and €21–27 million under optimistic assumptions. It is explicitly noted that this cost evaluation represents an assumption based business case rather than a field data driven economic assessment, as actual field failure rates and warranty data cannot be disclosed due to industrial confidentiality. Overall, the results demonstrate that structural improvements guided by failure analysis and parametric design evaluation can effectively enhance component durability. When interpreted within the stated assumptions and limitations, the presented approach highlights the potential technical and economic relevance of durability-driven design improvements for high volume manufacturing applications.