The effects of the support type and the material parameters on the elastic and elasto-plastic behaviors of thermoplastic laminated plates

ABSTRACT PhD Thesis THE EFFECTS OF THE SUPPORT TYPE AND THE MATERIAL PAREMETERS ON THE ELASTIC AND ELASTO-PLASTIC BEHAVIORS OF THERMOPLASTIC LAMINATED PLATES Tamer ÖZBEN University of Fırat Graduate School of Natural and Applied Science Department of Mechanical Engineering 2005, Page: 221 In this study, elastic and elastic-plastic stress analyses are carried out by the finite element method (FEM) for the thermoplastic composite laminate plates with rectangular hole. The layers in the laminated plates consist of the stainless steel woven fibers and the low density polyethylene (LDPE), respectively. The thermoplastic matrix composite layers are manufactured by using molds under heating and pres loading. The laminated plate ([0°/8°]2) and ([0°/-0o]2) under uniform transverse loading are formed by stacking four composite layers bonded symmetrically or antisymmetrically. Each layer with constant thickness is meshed into 64 elements and 288 nodes in the FEM solutions. Loading is gradually increased from yield point of the plate as 0.0001 MPa at each load step. The load steps are chosen 25, 50, 75 and 100. The elastic, plastic and residual stress components and expansion of the plastic zones are calculated according to load steps, different orientation angles, stacking sequences ([O°/0O]2 and [9°/-9°]2) and composite materials. In addition, the effects of the rectangular hole dimensions and the load steps on the elasto-plastic behavior are studied. Key Words: Elasto-plastic stresses analysis, finite element method, thermoplastic matrix composites, plates with rectangular hole, residual stress. XIII