HIGH ORDER IMPACT ELASTIC ANALYSIS OF CIRCULAR THICK CYLINDRICAL SANDWICH PANELS SUBJECTED TO MULTI-MASS IMPACTS

Abstract

THIS STUDY DEALT WITH THE DYNAMIC MODEL OF COMPOSITE CYLINDRICAL SANDWICH PANELS WITH FLEXIBLE CORES AND SIMPLY SUPPORTED BOUNDARY CONDITIONS UNDER LOW VELOCITY IMPACTS OF MULTIPLE LARGE OR SMALL MASSES USING A NEW IMPROVED HIGHER ORDER SANDWICH PANEL THEORY (IHSAPT). IN-PLANE STRESSES WERE CONSIDERED FOR THE CORE AND FACE SHEETS. FORMULATION WAS BASED ON THE FIRST ORDER SHEAR DEFORMATION THEORY FOR THE COMPOSITE FACE SHEETS AND POLYNOMIAL DESCRIPTION OF THE DISPLACEMENT FIELDS IN THE CORE THAT WAS BASED ON THE SECOND FROSTIG'S MODEL. FULLY DYNAMIC EFFECTS OF THE SOFT CORE AND FACE-SHEETS WERE CONSIDERED IN THIS INVESTIGATION. IMPACTS WERE ASSUMED TO OCCUR SIMULTANEOUSLY AND NORMALLY OVER THE TOP FACE-SHEET WITH ARBITRARILY DIFFERENT MASSES AND INITIAL VELOCITIES. THE CONTACT FORCES BETWEEN THE PANEL AND IMPACTORS WERE TREATED AS THE INTERNAL FORCES OF THE SYSTEM. IN THIS PAPER, NONLINEAR CONTACT STIFFNESS WAS LINEARIZED WITH A NEWLY PRESENTED IMPROVED ANALYTICAL METHOD. NUMERICAL RESULTS OF THE MENTIONED STRUCTURES WERE COMPARED WITH FINITE ELEMENT MODEL USING ABAQUS CODE.