Numerical modelling in large strain plasticity with application to tube collapse analysis

摘要: Numerical methods are proposed for the analysis of 2 or 3-dimensional large strain plasticity problems. A Finite Difference program, with 2-dimensional continuum elements and explicit time integration, has been developed applied to model axisymmetric crumpling circular tubes. New types mixed (Triangles-Quadrilaterals 2-D, Tetrahedra-Bricks 3-D) spatial discretization. These accurately incompressible plastic flow, without unwanted "zero-energy" deformation modes tangling over mesh. Elastic-plastic, rate dependent laws modelled a "radial return" algorithm. The transmission heat generated by work material dependence on temperature also included, enabling fully coupled thermo-mechanical analysis. A 2-D computer program developed, implementing numerical techniques described. Computational efficiency was essential, as scale, costly applications were intended. An important part contact algorithm, modelling interaction between surfaces. The tubes under axial compression ("concertina" mode) analyzed Numerically. Quasi-static experiments Aluminium modelled, using velocity scaling. Very strains in process; help tension tests, valid such ranges developed. Good agreement obtained predictions experimental results. Modelling choices mesh refinement, element type scaling studied, found have an influence predictions. Finally, scale impact steel tube at 176m/s performed. results compared well experiment, indicating differences behaviour low mechanisms. To conclude, procedures time- marching problems, medium velocities. fairly robust code successfully range