BLAST RESISTANCE OF STIFFENED SANDWICH PANELS WITH ALUMINUM CLOSED CELL FOAM

Abstract

IN THE PRESENT INVESTIGATION, RESPONSE OF THE STIFFENED SANDWICH FOAM PANELS WITH ALUMINUM CLOSED CELL FOAM SUBJECTED TO BLAST LOAD IS EXAMINED. THE PANELS HAVE THE METAL FOAM SANDWICHED BETWEEN TWO STEEL SHEETS. THE METAL FOAM HAS CLOSED CELL STRUCTURE. TO IMPROVE THE RESISTANCE OF THE SANDWICH FOAM PANEL AGAINST BLAST, STIFFENERS ARE PROVIDED AND THEIR DYNAMIC RESPONSE UNDER VARYING BLAST LOAD MAGNITUDES IS STUDIED. BLAST LOAD IS APPLIED USING THE BLAST EQUATIONS AVAILABLE IN LS-DYNA WHICH TAKES INTO ACCOUNT THE REFLECTION OF BLAST FROM THE SURFACE OF THE SANDWICH FOAM PANEL. THE FINITE ELEMENT BASED NUMERICAL SIMULATIONS FOR DYNAMIC ANALYSIS ARE PERFORMED EMPLOYING A COMBINATION OF SHELL AND SOLID ELEMENTS FOR STEEL SHEETS AND METAL FOAM, RESPECTIVELY. QUANTITATIVE ASSESSMENT OF THE DYNAMIC RESPONSE OF THE SANDWICH FOAM PANELS IS MADE, PRIMARILY FOCUSING ON THE PEAK CENTRAL POINT DISPLACEMENT OF THE BACK-SHEET (OPPOSITE TO EXPLOSION) OF THE PANEL. SEVERAL ANALYSES ARE CARRIED OUT WITH AN OBJECTIVE TO UNDERSTAND THE EFFECTS OF STIFFENER CONFIGURATION, FOAM THICKNESS, FOAM DENSITY, AND STANDOFF DISTANCE ON THE BLAST RESPONSE. THE RESULTS INDICATE THAT THE PROVISION OF THE STIFFENERS ALONG WITH THE METAL FOAM CONSIDERABLY INCREASE THE BLAST RESISTANCE AS COMPARED TO THE UNSTIFFENED PANELS WITH THE METAL FOAM.