Moment frame connections have high share to withstand deformation caused by earthquakes. Hence, connections of reinforced concrete structures must have sufficient plasticity in addition to resistance. Observations after earthquakes and the results of tests prove that structural damages have been more observed in the connections area. Implementation of reinforcement in limited volume of connection area is difficult and hence improving the behavior of the connection areas has been among the major issues discussed in structural engineering. In addition, corrosion in the bad environmental conditions is one of the main difficulties in implementing steels in concrete arming. Among alternative materials, FRP rebars that have higher durability, were given attention in recent years. In this study, the behavior of the element has been compared in these conditions by modeling the connection area with steel and FRP rebars.

Reinforcement of structural timber members with fibre reinforced polymer (FRP) rods offers merits over that of the conventional steel type. In recent times, near surface mounted (NSM) FRP reinforcement with timber has emerged as a promising alternative for reinforcing timber structures in both flexural and shear loading configurations. Previous investigations have shown that NSM FRP reinforcement technique has higher bond performance than externally bonded equivalents because it (NSM FRP technique) is able to utilise the full capacity of the FRP materials. In spite of these merits, the investigations and the use of this innovative technique are limited. In this paper, an experiment was conducted to investigate the bond characteristics and performance of NSM basalt FRP reinforcement with solid timber structures. In order to predict the performance of the reinforced beam structures, unreinforced control timber members of the same timber characteristics were tested. The results showed that the average bond capacity of the NSM FRP reinforced members was 16% higher than the corresponding unreinforced beams.

Study of behavior of building structures under blast loads is an important issue for design of high reliable structures made of concrete material. Hence, in previous studies the enclosed wall under blast loads, open-air explosion has been investigated through experiments. In this study, the experimental results reported in the literature for dynamic performance of a masonry wall subjected to high strain dynamic loads (i.e. contact blast and air burst test) are simulated numerically using finite element method (FEM) by utilizing soft particle hydrodynamics (SPH). Comparison of simulated numerical results with the experimental data demonstrates the ability and accuracy of FEM analyses in predicting the response of confined masonry walls subjected to dynamic loads.

Connections represent major challenges in the design of composite structures, mainly because they entail discontinuities in the geometry of the structure and material properties, and introduce high local stress concentrations. Despite some constructability complications, integrated connection could be a reliable solution. In this paper, the structural behaviour of an integrated connection for implementation between adjacent composite sandwich panels in rapid assembly buildings is studied. The integrated connection system consists of 3-D high density polyethylene (HDPE) skin faces, and cores of high-density polyurethane (PUR) foam integrated into the sandwich panels at the moment of their production. The study included experimental investigations regarding the mechanical and structural response of the connection under actual applied loads, and its torsional rigidity, rotational stiffness and behaviour under lateral loading is investigated. Using Finite Element modelling, the stress distribution and the mechanisms of failure are studied. The results show a good agreement between the numerical and experimental results.

The present work predicts the numerical progressive failure response and crack growth of finite plate laminated composites with cutout and multiple cracks under in-plane tensile and compressive loads. The ply to ply failure response of the finite plate is predicted using ABAQUS user define field variables subroutine approach, whereas the extended finite element method is used for examination of crack growth direction for multiple through crack of laminated composite finite plate. The subroutine predicted results are compared and validated with published experimental results and extended finite element method results. The effect of changing mesh size, fibre orientation, crack length, crack inclination angle on failure load, progressive stress intensity factor and damage toughness of various crack types is presented and discussed.

This study synthesizes the use of chemicals to prevent one of common concrete durability problems, alkali-silica reaction (ASR), and can help researchers (i) identify widely used potential chemicals and evaluate these chemical solutions to prevent ASR with proper understanding of mechanisms, and (ii) to identify the research gaps in order to develop guidelines and implementation plan on the use of these chemicals for future research.

n this paper, armchair rectangular monolayer graphene nanoplates were analyzed based on the assumption of orthotropic properties with different boundary conditions. For this purpose, the nonlocal elasticity and Kirchhoff theories were applied to analyze the small-scale effects on the armchair monolayer graphene nanoplates and obtain the static equation of the graphene nanoplates, respectively. As there were no readily accurate answers to the analyses of all the problems associated with nanoplates of different boundary and geometrical conditions, numerical methods were employed for obtaining approximate responses. One of the capable approaches to the analyses of the differential equations governing these types of plates is the meshless method. In this research, the Discrete Least Squares Meshless (DLSM) method was employed for the static analysis of rectangular nanoplates with different boundary conditions besides assessing the effect of nonlocal coefficient amount on the nanoplate deflection. According to the results of this investigation, it could be concluded that the method utilized here was suitable for solving the problems of nano-dimensions compared to the analytical and Galerkin meshless methods.

In this paper, a smoothed weighted function with the compact support is suggested to improve the numerical accuracy of blending elements for the extended finite element method (XFEM) applied to the crack problem. Such a weight function consists of the shape functions used for the meshless method, reflecting the characteristics of the enriched bases inside the blending element. The effectiveness of this weight function is validated through the numerical examples.

The use of elastic elements in actuators can be effective in improving their performance. The present paper examines the different layouts of the elastic element in actuators, choosing the appropriate design, and then designing a series elastic actuator for use in an active knee orthosis. For this purpose, the design elements of actuators were extracted using the knee data for walking. In the next step, considering the effect of the spring stiffness on the energy consumption and actuator’s peak power, its optimum amount for gait was calculated. Afterwards, the effect of adding the spring has been shown at an optimal value. Since the human knee in a gait cycle involves position and force control, designing an efficient controller to track the force and position of the knee during the gait cycle is the next section of this study. Due to the specific application of this actuator, its volume and size are important for the user. For this reason, it is necessary to design and construct an actuator with a suitable size and weight, with good output. For this purpose, a lightweight and low volume actuator was fabricated.

Failure analyses require more and more reliable and robust approaches to structural response prediction. This represents a quite complex task to be accomplished especially when dealing with historical or ancient constructions in seismic geographic areas. The paper is aimed at providing approaches to the analysis of buildings alternative to simplified methods usually adopted in professional practice, which do typically involve drastic simplifications of the fabric. The approach allows developing full holonomic non-linear analyses for forecasting the behavior of structural panels present in the structural system, and it results in higher reliability and flexibility than ordinary procedures that are generally adopted in commercial software and are typically based on gross simplifications of the real structure. The presented method allows taking into account the real geometry of the masonry building under analysis, also including a number of elements such as architraves, tendons or reinforcements possibly incorporated into the walls. Besides the consistent improved reliability in performing structural analyses under quasi-static loads, the main potential of the approach is related to the possibility of developing its extension for performing dynamic analyses quite easily.