Experimental and numerical models to study the creep behavior of the unidirectional Alfa fiber composite strength by the photoelasticity method

International audienceIn this paper, we propose an experimental and numerical model to study the creep behavior of the unidirectional Alfa fiber composite strength by the photoelasticity method. To have better mechanical properties, chemical treatment is made for Alfa fibers. Tensile tests are made to predict the Young modulus and tensile strength. These tests confirm that the chemical treatment during 48 Hours of Alfa fibers collected from the south region gives the best results. After that, specimens are made in Medapoxy STR resin and treated Alfa fibers of the south region. All fibers of specimens are arranged approximately in multiple hexagonal clusters embedded in the matrix. For the micromechanical fiber stress redistribution or load sharing theory to be applied, clusters must minimally contain one broken fiber. Consequently, we have a stress perturbation due to a fiber fracture, which propagates to the nearest-neighbor fibers. This perturbation enables us the photoelastic visualization of the fracture events during the creep tests. The contour diagram and fringe values give us the accurate distribution of stress near broken fibers showing local shear stress concentrations during the time. To simulate the creep response and failure mechanism, the Tsai–Wu failure criterion was applied on ANSYS explicit dynamic software. Because it merges between experimental tests and numerical simulation, the present study offers a real scientific contribution in the creep behavior of biobased composite strength by the photoelasticity method

Free vibration analysis of non-symmetric FGM sandwich square plate resting on elastic foundations

In this study, free vibration analysis of simply supported sandwich plate resting on elastic foundation is examined. In this model, the displacements vary as a sinusoidal function across the plate thickness and satisfy zero shear stress condition at the top and bottom surfaces of the plate. The governing equations are derived by employing the principle of Hamilton, These equations are solved via Navier type and the dynamic results are presented by solving eigenvalue problems. The numerical results obtained through the present analysis for free vibration are presented and compared with those available in the literature