عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Because of wide applications of composites at low temperatures, mechanical properties of glass fiber-reinforced epoxy have to be assessed at low temperatures. Experimental or analytical investigation on the tensile failure behavior of glass/epoxy laminated composite with/or without stress concentration subjected to thermo-mechanical static loadings at low temperatures has not been done yet. In the present work, a finite element model was developed to perform the progressive failure analysis of quasi isotropic composite plates at room temperature and -60Â°C. In this model Hashin failure criteria was used to detect possible failures. Quasi-isotropic laminates with stress concentration was selected. Full characterization of UD composite at -60Â°C was performed by a set of experimental tests. These results were used as input data for finite element model. The load is increased step by step. For each given load, the stresses (mechanical and thermal) are evaluated and the appropriate failure criterion is applied to inspect for possible failure. For the failed element, material properties are modified according to the failure mode using a non-zero stiffness degradation factor. Then, the modified NewtonâRaphson iteration is carried out until convergence is reached. This analysis is repeated for each load increment until the final failure occurs and the ultimate strength is determined. The present method yields results in a reasonable agreement with the experimental data at room temperature and -60 ÂºC. The effect of low temperature on the failure mechanism of the plates was also determined.