Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Stress Concentration Analysis in Pseudoelastic Thin Sheets using the Finite Element Method
Submission Author:
Bruno Felippe Silva , RJ
Co-Authors:
Bruno Felippe Silva, Luís Felipe Guimarães de Souza, Ricardo Alexandre Amar de Aguiar, Pedro Manuel Calas Lopes Pacheco
Presenter: Bruno Felippe Silva
doi://10.26678/ABCM.COBEM2023.COB2023-0759
Abstract
Shape Memory Alloys (SMA) are materials that have a strong thermomechanical coupling associated with phase transformation processes. These alloys have special characteristics in terms of their stress-strain-temperature behavior, making them attractive for use in various applications of interest in engineering, such as actuators, intelligent structures and mechanical vibration absorbers. When submitted to thermomechanical loadings, SMAs present a complex nonlinear behavior and require the use of specific methodologies to evaluate their performance and integrity. The design of mechanical components with complex geometries, involving geometric discontinuities such as notches and holes, has been treated through simplified mechanical design approaches involving stress concentration factors, both for static loads and during cycles of mechanical and/or thermal loads. The presence of plastic deformations increases the complexity of the analysis due to stress redistribution and non-linearities present, and mechanical design approaches involving elastoplastic stress concentration factors have also been used. Similarly, strains associated with the phase transformation process in shape memory alloys promote a stress field redistribution effect. In this work the phenomenon of stress concentration in thin sheets of pseudoelastic SMAs is investigated through numerical simulations using a model based on finite elements. The effect of the redistribution of the stress field resulting from the phase transformation process is investigated, with the objective of identifying specific concentration factors. The pseudoelastic behavior is modeled using a constitutive model for SMAs. The results show different behaviors from those observed in materials with elastic and elastoplastic behavior, indicating the importance of considering the effect of phase transformation during the loading of mechanical components of pseudoelastic shape memory alloys.
Keywords
Shape Memory Alloys, Pseudoelasticity, stress concentration, Finite Element Method, modeling
