EXPERIMENTAL AND NUMERICALSTUDIES OF THE COLLAPSE OF THIN TUBES UNDER AXIAL COMPRESSION

Abstract

EXPERIMENTS ON ALUMINUM TUBES WITH VARYING D/T RATIOS AND THEIR FINITE ELEMENT SIMULATION HAVE BEEN PERFORMED TO STUDY THEIR COLLAPSE MECHANISM AS WELL AS THE LOAD COMPRESSION AND THE ENERGY ABSORPTION RESPONSES. CONVERGENCE STUDIES WITH RESPECT TO MODEL PARAMETERS LIKE LOAD STEP SIZE, MESH DENSITY AND BOUNDARY CONDITIONS HAVE BEEN ESTABLISHED. DEPENDENCE OF DEFORMATION CHARACTERISTICS AND ENERGY ABSORPTION RESPONSE ON BOUNDARY CONDITIONS (END FIXITY), GEOMETRICAL PARAMETER- D/T RATIO, AND MATERIAL PARAMETERS - YIELD STRENGTH AND TANGENT MODULUS, HAVE BEEN STUDIED. TRANSITION OF DEFORMATION MODE SHAPES FROM AXISYMMETRIC CONCERTINA MODE TO NON AXISYMMETRIC DIAMOND PATTERN OWING TO TUBE WALL THICKNESS ECCENTRICITY UNDER PERFECTLY AXISYMMETRIC TUBE END CONDITIONS HAS BEEN SIMULATED. VALIDATION AND COMPARISON OF NUMERICAL SOLUTION WITH THE EXPERIMENTAL RESULTS HAVE BEEN CARRIED OUT.