| Abstract [eng] |
The growing demand for light weight structures result in increasing replacement of metal parts by composite structures. It makes up about 65 per cent of all the composites produced today and is used for boat hulls, tanks, surfboards, sporting goods, swimming pool linings, building panels and car bodies. The wide use of composite structure comes from the ultimate strength of the glass fibers, core and resin combination. In the sandwich composite structure normally the bending loads are carried by the force couple formed by the facesheets and the shear loads are carried by the lightweight core material. The critical properties of the sandwich structure depends upon the application of the structure. The main theme of this project is to perform stress analysis on the composite sandwich structure laminated by glass fiber reinforced plastics. In this thesis work a constitutive model for the numerical prediction of strength of Sandwich Composite Structure material behavior under three point bending, tension test and compression test. A tension test of the facesheet allowed verification of the material model and failure criteria of GFRP. Three-point bending of the sandwich and the compression of cylinder tests allowed verifying of the sandwich structure model. Using experimentally obtained specific material properties, a numerical finite element model of a hollow cylindrical structure was designed and experimentally verified. The designing and simulation of the model has been done in LS-PREPOST Beta 4.2 and LS-DYNA v.971 R7.0.0. The stress analysis on the composite sandwich structure has been performed and the comparison of the results shows a good co-relation between finite element and experimental results. This methodology can be applied for all types of composite sandwich structures to determine the strength of the structures. . |
