Abstract: Introduction: Sandwich composite structures is a type composite material which are consist of two thin face layers and thick core in order to obtained higher strength and lightweight material. The thin layers are high strength materials, whereas the core layer is lightweight materials. Sandwich composite structures have been used many engineering applications, such as aircrafts, space vehicles, automotive industries, defence industries and civil engineering applications because these structures have higher strength-weight ratios, more lightweight and ductile properties than classical materials. With the great advances in technology, the using of the sandwich composite materials is growing in applications. With the increased use of sandwich composites, understanding the mechanical behavior of sandwich composites is very important. It is known that if the stress of a material is bigger than the elastic limit of the material, the material perform plastic or elasto-plastic behavior and the material do not return to the initial configuration. After this that permanent deformation and deflections occur in the material and the material can damage. So, plastic or elasto-plastic problems are very important for structural elements because their losing strength. In sandwich composite structures, elasto-plastic behavior occur frequently because their structural components. Sandwich composite structures consist of layered laminates. In the between among of the layered laminates, residual stress occur. As a result, the elastic-plastic stress stresses are seen frequently in the composite structures. Understanding the elasto-plastic analysis and behaviour of sandwich composite structures is very important for safety of sandwich composite structures. Aim: In this study, the elasto-plastic analysis of a sandwich composite rectangular plate is investigated and analyzed under mechanical loads. The constitute model of the materials are considered as bi-linear elasto-plastic stress-strain relation. In the numerical examples, elasto-plastic deflections are calculated and discussed. The effects of the material and dimenison ratios on the static responses of the sandwich composite rectangular plate are examined in the elasto-plastic behavior. Also, the difference between the elasto-plastic analysis and the elastic analysis is investigated for different values of the load. Content: In accordance with this purpose, a sandwich composite rectangular plate is modeled with using three dimensional solid model. In the selection of the structural materials, the face sheet is considered as a metal material and the core material is considered as a light weight isolation material. The boundary conditions are selected as clamped for all edges. Constraints: In this paper, the constitute model of material is considered as a bi-linear elasto-plastic stress-strain relation. The nonlinear material stress-strain relation is not modeled. Method: The mechanical model of the sandwich composite rectangular plate is modeled as three dimensional solid model in order to get sensitive results. In solution of the problem, three-dimensional (3-D) finite element method is used. In the material model of the sandwich composite rectangular plate, the face sheet and core materials are modelled as isotropic and bi-linear elasto-plastic material model. The boundary conditions of the sandwich composite rectangular plate is assumed as clamped in the all boundaries. In the solution of the problem, the sandwich composite rectangular plate is modelled and analysed in ANSYS Workbench finite element software. In this paper, the elasto-plastic deflections are obtained and discussed. Findings: The numerical results shows that that material distribution and the dimensional of the face sheet layers have very important role on the elasto-static behavior of the sandwich composite rectangular plate. Choosing the suitable material distribution parameter, the plate can be getting more strength. Conclusion: In this paper, the elasto-plastic static deflections of the sandwich composite rectangular plate is investigated by using three-dimensional finite element method. In the solution of the problem, the sandwich composite rectangular plate is modelled and analysed in ANSYS Workbench finite element software. The effects of the material and dimenison ratios on the static responses of the sandwich composite rectangular plate are examine and in both the elasto-plastic and elastic analysis. The material and dimension ratios have very important role on the elasto-static behavior of the sandwich composite rectangular plate.
Anahtar Kelimeler: Sandwich Plates, Elato-Plastic Anlaysis, Finite Element Method
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