In this article, several aspects of material parameter identification are addressed. We compare several methods to identify material parameters of a constitutive model for small strain, linear elastic transverse isotropy based on experimental data of specimens made from composite plates. These approaches range from identifying the five material parameters from purely analytical considerations to the fully numerical identification on the basis of finite elements and various data provided by digital image correlation (DIC). The underlying experimental tests range from purely uniaxial tensile tests with varying fiber orientation to shear and compression tests. A specific measuring instrument has been developed for the latter tests to obtain unique material parameters—motivated by the concept of local identifiability. Besides, we compare the numerical differentiation, which is the common procedure in parameter identification, with the fully analytical derivation of sensitivities within the DIC/FEM approach.

The insertion of holes into laminates can be done by producing a fiber reinforced composite plate and, subsequently, drilling the borehole. Alternatively, we can bypass the fibers around the final hole before injecting the matrix material. In the first case, the spatial distribution of the axis of anisotropy, and the structural tensor concerned, are spatially constant. In the second case, i.e. the fiber circumplacement around the hole, a space-dependent anisotropy has to be considered. Instead of the common approach of defining region-wise constant fiber orientations, we propose a continuous formulation of fiber orientations using streamlines. To estimate the final stress and strain state for a unidirectional composite plate, three-dimensional finite element simulations are performed, where spatially constant transverse isotropy is compared to inhomogeneously distributed fiber orientation around the hole. It will turn out that the resulting stress states lead to both reduced stress amplitudes in loading direction as well as compressive strains in lateral direction. A detailed mathematical derivation of the basic equations accompanies the investigations.

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Since 1970, the steel plate shear wall is regarded as the first choice among latest load resisting systems and employed in several important and modern buildings. In the early and during the 1970s, the steel plate shear walls were used in modern buildings in Japan and United States to improve the seismic behavior of structures. It can be concluded from existing researches that the steel plate shear walls have considerable strength and stiffness in comparison with other systems. In order to find the optimum size that minimizes structure’s weight under the applied load and also fulfilling the structural requirements and restrictions optimization is required. In this study, tracing the shear wall elements with the lowest strain energy through using the topology optimization based on finite element method and removing them according to particular mechanism is investigated. This procedure gives us the optimized shape of steel plate shear wall. For this purpose, a steel plate shear wall is modeled in Abaqus to obtain its force-displacement curve and subsequently the force-displacement relationship is acquired using virtual work method and MATLAB programming.

In order to withstand lateral loads such as wind and seismic loads, various systems have been proposed so far. Among these, one of the latest one is steel plate shear wall system that has been used in several high and important buildings in different seismic zones of countries including the United State and Japan. Comparing to other lateral load resisting systems such as braces and concrete shear walls, the steel plate shear walls have relative advantages. Additionally, a number of studies and experiences indicate that this type of shear wall has considerable strength and stiffness compared to other systems. Due to architectural requirements, openings are usually cut in panels of steel plate shear walls during construction. It is clear that the size and location of openings affect the performance of steel plate shear walls during earthquake. Therefore, two steel plate shear walls, one with stiffeners and other without stiffeners are considered and their performance are assessed under applying openings with different sizes. The shear walls are modeled in Abaqus and analyzed using finite element method to find the most critical opening size and location. For this reason, the entire plate of the shear wall is used; moreover, the force-displacement curves are obtained after the analysis to compare the shear walls performance.