AXIAL CRUSHING OF UNI-SECTIONAL BI-TUBULAR INNER TUBES WITH MULTIPLE OUTER CROSS-SECTIONS

Abstract

INCREASE OF ENERGY ABSORPTION ALONG WITH SMOOTH LOAD DISPLACEMENT CURVE, REDUCED PEAK FORCE AND HIGH MEAN CRUSHING FORCE IS THE KEY IN THE MODERN DYNAMIC DESIGN OF STRUCTURES. IN THIS REGARD, A NEW METALLIC TUBULAR CONFIGURATION CONSISTING OF UNI-SECTIONAL BI INNER TUBES WHICH ARE PLACED INSIDE AN OUTER TUBE WITH MULTIPLE VARIED CROSS-SECTIONS IS PROPOSED AND CRUSHED UNDER AXIAL DYNAMIC LOADING. A NUMBER OF CONFIGURATIONS ARE PROPOSED RANGING FROM SIMPLE TO COMPLEX POLYGONAL SECTIONS DEFINED IN THREE GROUPS. DEFORMATION MODES AND ENERGY ABSORPTION CHARACTERISTICS SUCH AS PEAK CRUSHING FORCE, MEAN CRUSHING FORCE, AND SPECIFIC ENERGY ABSORPTION ARE DETERMINED AND DISCUSSED FOR EACH CONFIGURATION. THE PROPOSED ARRANGEMENT SHOWS A STABLE CRUSHING, GIVING HIGHER VALUES OF CRUSH FORCE EFFICIENCY. IN ORDER TO SELECT THE MOST SUITABLE CONFIGURATION, ON THE BASIS OF MAXIMUM SPECIFIC ENERGY ABSORPTION, MAXIMUM CRUSHING FORCE AND MINIMUM PEAK FORCE, A ROBUST DECISION MAKING METHOD KNOWN AS COMPLEX PROPORTIONAL ASSESSMENT (COPRAS) IS IMPLEMENTED. THE RESULTS INDICATE THAT THE PROPOSED CONFIGURATION WITH OUTER AND INNER HEXAGONAL TUBES’ ARRANGEMENT IS THE BEST CONFIGURATION IN TERMS OF ENERGY ABSORPTION CHARACTERISTICS. THE CONCLUSION IS DEPENDENT ON THE ASSIGNED WEIGHTING PARAMETERS WHICH ARE QUITE SENSITIVE FOR THE RESULTS, DEMANDING A CAREFUL SELECTION AS PER THE SPECIFIC APPLICATION AND MAY ALTER THE BEST POSSIBLE CHOICE.