Design of a heterogeneous interior notched specimen using shape optimisation approach

• Autor(a) principal: Conde, Mariana Peneda
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/31334
• topic: Heterogeneity; Mechanical testing; Shape optimisation; Finite element method (FEM); Strain measurements; Material behaviour; Design by optimisation

Nowadays, virtual predictions are essential in the design and development of new engineering parts. A critical aspect for virtual predictions is the accuracy of the constitutive model to simulate the material behaviour. A state-of-the-art constitutive model generally involves a large number of parameters, and according to classical procedures, it requires many mechanical experiments for its accurate identification. Fortunately, this large number of mechanical experiments can be reduced using heterogeneous mechanical tests, which provide richer mechanical information than classical homogeneous tests. However, the richness is much dependent on the specimen’s geometry and can be improved with the development of new specimens. Therefore, this work aims to design a uniaxial tensile load test that presents heterogeneous strain fields using a shape optimisation methodology, by controlling the specimen’s interior notch shape. The optimisation problem is driven by a cost function composed by several indicators of the heterogeneity present in the specimen. Results show that the specimen’s heterogeneity is increased with a non-circular interior notch, compared to a circular one. The achieved virtual mechanical test originates both uniaxial tension and shear strain states in the plastic region, being the uniaxial tension strain state predominant.