Papers by Keyword: Elastic-Plastic FEM

Abstract: This study evaluates the effect of the compression between the punch and the die on spring-back after the punch reaches the dead point. Utilizing the elastic-plastic FEM, the forming and spring-back process of aluminum alloy V-shape sheet is simulated. The investigation is also carried out through experiment. It is shown that spring-back decreases as the ratio of the average pressure and tensile strength increases when the ratio is small; Spring-back increases slightly as the radius of the punch increases from 8mm to 16mm. The results of the 2D plain strain element are in good agreement with the experiment results.

Abstract: In a roll forming process, a desired profile is produced through continuous bending of a sheet metal strip. Occurrences of spring back, twist, and bow are major defects in roll formed profiles. We developed a dedicated analysis program based on the elastic-plastic finite element method to simulate roll forming processes with asymmetrical shaped rolls. We applied the augmented Lagrangian technique in contact algorithm and a pre-determined deformation region division method for computation efficiency. A simplified cross section produced via three passes of roll forming has been experimented to be measured in the amounts of twist and bow occurred after roll forming. The performance of the developed FEA tool has been verified with measurements in terms of accuracy. The tool has been evaluated in terms of computation efficiency by comparison of without region division method.

Abstract: In order to reveal the mechanism of deformation, disintegration and failure of shallow landslides of coal measure soil, through contact elastic-plastic FEM with shear strength reduction, the paper analyzes shallow landslides stability, calculates shallow landslides safety factors, and reveals the mechanism of deformation, disintegration and failure of shallow landslide of coal measure soil. The results are shown as follows: during shallow landslides of coal measure soil, the displacement of sliding mass sliding along sliding surface, the plastic strain of sliding mass and sliding mass sliding state along sliding surface don’t change simultaneously; adopting contact elastic-plastic FEM algorithm may better reflect the actual state and sliding process of shallow landslides of coal measure soil. It can help faithfully reflect real situations of shallow landslides like deformation, disintegration and failure of shallow landslide of coal measure soil, and it may afford one method that can be used as a reference of the stability analysis, accurate evaluation and forecast of this type of landslide.

Abstract: In previous studies, the elastic stress field near the crack tip was investigated by digital image correlation and the 2-D intelligent hybrid method. In this study, the 2-D nonlinear hybrid method was developed to analyze the elastic-plastic singular stress field near the crack tip from the displacement data obtained by digital image correlation. Then, the 2-D nonlinear hybrid method was carried out to evaluate stress, strain and J integral. The 3-D elastic-plastic finite element method was conducted on the same specimen as the experiment, and the validity of this approach was discussed from the comparison of the experiment and 3-D finite element method.