Reza Kamgar

The design and fabrication of bending-active structural configurations pose significant challenges due to the nonlinearity of bending-active systems, material properties, the mutual relationship between element sizing and deformation behavior, the assembly process, and the initial flexibility. The enormous domain of construction parameters requires a specific sequence for morphological purposes. Reviewing the systems’ deformation behavior has posed the challenge of associating effective formatting parameters with their postformed load-deformation response. The present study evaluates a single-support roof that can adjust to various situations by utilizing scissor-like segments and bending-active elastic beams. Additionally, the scissor-like structural system reduces the height of the covering system to the ground in three stages by utilizing telescopic rods to increase the size, causing an expansion in bending in the elastic rods parallel to the ground. Subsequently, following configuration instructions, the structure is tested under various loads to evaluate its behavior. The second part of the study focuses on a shading system incorporating five adaptable elements. These elements are designed to provide different light levels, visibility, and thermal comfort throughout the day and seasons. The universal thermal climate index was calculated at two different times and seasons. The optimization process involved five design variables, specifically the rotation angle of dynamic elements, which can range from 0° to 180°. This aims to balance between thermal comfort and sky visibility percentage.

The present research applies a 2D refined plate theory and isogeometric analysis (IGA) for free vibration analysis of functionally graded (FG) sandwich plates, whose governing equations are treated based on a unified formulation (UF), and nonuniform rational Lagrange (NURL)-based IGA technique. The constitutive model of FG materials is approximated via a Voigt’s rule of mixture based on an equivalent single-layer (ESL) theory. The present framework offers several advantages, including high precision of vibration response by employing higher-order plate theory and the capability of NURL basis functions to capture the exact form of plate geometries. Moreover, higher-order theories postulated by the UF are exempt from the Poisson locking phenomenon and do not require a shear correction factor. Additionally, by employing UF, the effect of thickness stretching on vibration response is considered. Furthermore, higher-order NURL basis functions effectively mitigate shear locking. A large numerical investigation shows the accuracy of results and investigates the effects of several key parameters, such as gradient index, thickness-to-length ratios, layer-to-thickness ratios, and boundary conditions, on the vibration response of FG sandwich plates.

Nowadays, with the widespread supply of very powerful laboratory and computer equipment, it is expected that the analyses conducted for geotechnical problems are carried out with very high precision. Precise analyses lead to better knowledge of structures’ behavior, which, in turn, reduces the costs related to uncertainty of materials’ behavior. A precise analysis necessitates a precise knowledge and definition of the behavior of the constituent materials, which itself requires applying an appropriate constitutive model to show the behavior of materials. Constitutive models used in the generalized plasticity framework are very powerful constitutive models for the simulation of sand behavior. However, the simulation of a cyclic behavior in these models, especially the simulation of the undrained cyclic behavior, is not well-recognized. In this study, in order to eliminate the weakness of generalized constitutive models under cyclic loading, a new equation is presented to substitute the so-called coefficient of the discrete memory factor to consider the loading history in such a way that the plastic modulus is modified during reloading and, as a result, more appropriate predictions of sand behavior are obtained. The performance accuracy of the proposed coefficient was evaluated in accordance with the experimental data. Finally, the results show that after using the modification of the loading history coefficient, predictions of the constitutive model are significantly improved.