چكيده به لاتين
Nonlinear physical behavior of polymer composites has been widely studied. Due to the fact that at least two constituents with largely different thermomechanical properties compose them, studying their mechanical response has been a challenge. This nonlinear behavior includes development of various damage mechanisms in the microstructure of the material, which cause irreversible changes. These materials are used in a broad range of industries, whereas in the past they were mainly used in the aerospace industry. In order to achieve the full potential of these materials and design reliable components and structures, the aforementioned complexities should be taken into account. Accordingly, elastic, linear analysis of PMCs is not adequate for many practical issues. In this study, tension and compression tests were carried out on unidirectional carbon/epoxy specimens to measure the irreversible deformations occurring along the action planes. Unidirectional specimens with fiber orientations of 15°, 30°, 45°, 60° and 90° were tested both in tension and compression to study the yielding behavior of the matrix in varied stress states. Results suggest that in the case of UD laminates, accumulation of plastic shear strains on a critical plane controls the response. Using the experimental measurements, yielding behavior of the matrix under different loading conditions was modeled using two deformation mechanisms. This physically-based modeling strategy is able to reproduce the complex effects of multi-axial loading.
