A Comparison of the Effects of Stress Concentrations in Laser-Cut PMMA Under Static and Centripetal Loading

Abstract

A number of studies have looked how resultant stress concentrations in designs can have a detrimental effect on finished parts. Recently student projects at Solent University experienced issues with uncertainty in stress concentrations from laser cutting of polymeric materials. This study looks at conventional tensile testing to evaluate PMMA (acrylic) subjected to tensile testing, varying the presence of fillet radii on section changes, and compare the findings to finite element analysis (FEA) models. In addition, parts are tested under centripetal loading to compare the effects of stress concentrations when a component is subjected to centripetal force and angular acceleration, in the form of a horizontal fan blade. The centripetal testing will avoid the effects of impulse on specimens but allow comparisons to be drawn between physical testing (with limited controlled variables) using a motor hub and FEA results. The findings will be used in teaching undergraduates and also help with future student projects.