Application of adaptive mesh strategies for deformation-based digital image correlation

• Grant number: 24/05884-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2024
• End date: July 31, 2025
• Field of knowledge: Engineering - Mechanical Engineering - Mechanics of Solids
• Principal Investigator: Ricardo Afonso Angélico
• Grantee: Felipe Lorenzo Andrade de Oliveira
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

The study of crack initiation and propagation is primary to the fracture mechanics domain and essential for developing new materials or establishing inspection techniques. Such a study is relevant for refractory ceramics adopted as thermal insulators in high-temperature industrial applications. In particular, mechanical and thermal tests are essential in measuring properties and contribute to the material selection process. Such tests can be assisted using nonintrusive measurement techniques, in particular, by Digital Image Correlation technique, which enables to obtain full-field information concerning the displacement and strain fields in a loaded configuration (thermal and mechanical loads). Full-field information, together with numerical models, enables identifying properties intrinsic to the fracture behavior, helping to design better materials and understand complex deformation mechanisms. Identifying the crack location is a challenge for DIC techniques and requires special treatment of the correlation process to get reasonable resolution around the crack. Global DIC approaches can benefit from mesh refinement strategies to improve the identification of the displacement field and, consequently, the crack's location. In this context, the present research aims to develop mesh refinement strategies to improve the image correlation in cracked specimens. Also, aiming to achieve a compromise between computational cost and analysis accuracy. The adaptativity approach will be developed using the Application Programming Interface (API) of the GMsh software, which has several features to control the element mesh size distribution, by controlling mesh size parameters using strain and local gray-level residue. The evaluation of the mesh refinement algorithm is established in terms of reducing global gray-level residual and computational cost. The present research contributes to the DIC processing, getting more information on specific regions based on strain and gray level residual information.