Showing 3 results for Parvizian
M. Mashayekhi, S. Ziaei-Rad, and J. Parvizian,
Volume 25, Issue 2 (1-2007)
Abstract
The continuum mechanic simulation of micro-structural damage process is important in the study of ductile fracture mechanics. In this paper, the continuum damage mechanics model formulation proposed by Lematire has been validated against ductile damage evolution experimentally measured in A533B-C1 steel under stress triaxiality conditions. First, a
procedure to identify the model parameters from test was defined. Then, the finite element model was used to simulate the experiment carried out on a notched flat rectangular bar. Good agreement was observed between the experimental results and finite element predictions. Next, the identified parameters on A533B-C1 steel were used to simulate the results from a conventional tensile test by finite element method. The specimen was prepared according to ASTM E08 standard. The stresses at necking stage and ultimate load calculated by the damage based method were compared with those obtained from the test. The comparisons indicate a good agreement between the simulated and the experimental results.
Y. Mirbagheri, H. Nahvi, J. Parvizian,
Volume 34, Issue 2 (1-2016)
Abstract
Grid dispersion is one of the criteria of validating the finite element method (FEM) in simulating acoustic or elastic wave propagation. The difficulty usually arisen when using this method for simulation of wave propagation problems, roots in the discontinuous field which causes the magnitude and the direction of the wave speed vector, to vary from one element to the adjacent one. To solve this problem and improve the response accuracy, two approaches are usually suggested: changing the integration method and changing shape functions. The Finite Element iso-geometric analysis (IGA) is used in this research. In the IGA, the B-spline or non-uniform rational B-spline (NURBS) functions are used which improve the response accuracy, especially in one-dimensional structural dynamics problems. At the boundary of two adjacent elements, the degree of continuity of the shape functions used in IGA can be higher than zero. In this research, for the first time, a two dimensional grid dispersion analysis has been used for wave propagation in plane strain problems using B-spline FEM is presented. Results indicate that, for the same degree of freedom, the grid dispersion of B-spline FEM is about half of the grid dispersion of the classic FEM.
Aliakbar Taghipour, J. Parvizian, S. Heinze, A. Duester, E. Rank,
Volume 37, Issue 1 (9-2018)
Abstract
finite cell method, are employed to compute a series of benchmark problems in the finite strain von Mises or J2 theory of plasticity. The hierarchical (integrated Legendre) shape functions are used for the finite element approximation of incompressible plastic dominated deformations occurring in the finite strain plasticity of ductile metals. The computational examples include the necking under uniaxial tension with notched and un-notched samples and the compression of a perforated plate. These computations demonstrate that the high-order finite element methods can provide a locking-free behavior with a pure displacement-based formulation. They also provide high convergence rates and robustness against high mesh distortions. In addition, it is shown that the finite cell method, on the top of the aforementioned advantages, provides easy mesh generation capabilities for highly complex geometries. The computational results are verified in comparison with the results obtained using a standard low-order finite element method known as the F-bar method. The numerical investigations reveal that both methods are good candidates for the plasticity analysis of engineering materials and structures made up of ductile materials, particularly those involving complex geometries.
