Optimization of Product Handle Material Mechanical Properties for Improved Ergonomics Using Finite Element Method and Subjective Response

Abstract

AbstractFinite element method (FEM) is being increasingly used in ergonomics and biomechanics lately, since it can provide various quantitative results, which are otherwise not obtainable, however, it does not provide any results in terms of subjective rating. Therefore, in this paper we investigated to what extent the quantitative results of FEM can be used to predict the subjective comfort rating. We focused on the optimization of the product handle material parameters to lower the contact pressure while maintaining the stability of the handle in hands. Basic criterion of pressure discomfort threshold has been used for the FEM approach. Deformable meta-material interface layer of a product handle has been manufactured using 3D printing technology based on the obtained results. Additionally, one handle with higher stiffness, one with lower stiffness and handle made from hard plastic have been manufactured for comparison. A sawing task has been utilized for the evaluation of the subjective comfort rating. Results have shown the material properties of the deformable handle obtained by FEM with optimization yielded in higher comfort rating when compared to the hard-plastic handle while maintaining same stability. Stiffer deformable handle showed slight increase in comfort rating with similar perceived stability, while softer deformable handle was rated lower in terms of subjective comfort and provided less stability. Results indicate FEM can be successfully used for initial material parameter identification; however subjective response needs to be considered for fine tuning of the material behavior.KeywordsProduct handleSubjective comfort ratingMaterial propertiesFinite element method