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Analysis of arbitrary propagation of strong discontinuities in bidimensional solids using the boundary elements method

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Author(s):
Rafael Antonio Amaral Pedrini
Total Authors: 1
Document type: Master's Dissertation
Press: São Carlos.
Institution: Universidade de São Paulo (USP). Escola de Engenharia de São Carlos (EESC/SBD)
Defense date:
Examining board members:
Osvaldo Luis Manzoli; Tulio Nogueira Bittencourt; Humberto Breves Coda
Advisor: Osvaldo Luis Manzoli
Abstract

This work has the objective of bringing contributions to the numeric simulation using the boundary elements method (BEM) to model the initiation and propagation of strong discontinuities in the displacement field in bidimensional solids. The initiation process of strong discontinuities characterizes the failure process of material, which can be associated with the fracture of quasi-brittle materials and slip lines in ductile materials such as metals. The effect of the displacement jump of a discontinuity interface embedded in an internal cell is provided by an equivalent strain field over the cell. This model allows the study of arbitrary crack growth using a fixed mesh defined before the analysis. The dissipative process in the cell interface is described by an isotropic damage model in the continuum approach of strong discontinues. Alternatives that come from relaxing the static consistencies and the influence of the mesh alignment are analyzed. An adaptative algorithm for internal cells creation is also presented to capture the path of the crack growth during the loading process. This algorithm intends to overcome some convergence problems found in models with predefined meshes and also to reduce the computational efforts. The geometric characteristics of the generated internal cells are defined using the crack orientation, given by the failure criterion, to provide a better numerical efficiency. The results obtained with the proposed formulation are compared with the ones obtained with other numerical methods and also from experiments. (AU)