Using experimental data and numerical simulations, a new combined technique is presented for characterization of thin and thick orthotropic composite laminates. Four or five elastic constants, as well as ply orientation angles, are considered as the unknown parameters. The material characterization is first examined for isotropic plates under different boundary conditions to evaluate the method's accuracy. The proposed algorithm, so-called CPAM (Combined Programs of ABAQUS and MATLAB), utilizes an optimization procedure and makes simultaneous use of vibration test data together with their corresponding numerical solutions. The numerical solutions are based on a commercial finite element package for efficiently identifying the material properties. An inverse method based on particle swarm optimization algorithm is further provided using MATLAB software. The error function to be minimized is the sum of squared differences between experimental and simulated data of eigenfrequencies. To evaluate the robustness of the model's results in the presence of uncertainty and unwanted noises, a sensitivity analysis that employs Gaussian disorder model is directly applied to the measured frequencies. The results with high accuracy confirm the validity and capability of the present method in simultaneous determination of mechanical constants and fiber orientation angles of composite laminates as compared to prior methods.

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A new method combining experimental and numerical data is proposed to simultaneously determine the mechanical properties and damage parameters in multilayered composite plates. Studied parameters are mechanical properties of each layer, width and length of delamination zone, location of damage’s center, and interface location of the damage. In this method, the PSO optimization procedure based on a CPAM algorithm uses vibration test data along with their corresponding numerical solution. Vibration data are the plates’ natural frequencies and mode shapes obtained in the modal laboratory. In order to efficiently investigate the studied parameters, the numerical solution is investigated by a commercial finite element package. The error function constitutes two parts, one part is included by the sum of the squared differences between experimental and numerical natural frequencies and the other is based on the mode shapes data. The mode shapes’ curvatures are also utilized to achieve high sensitivity to small faults. Moreover, by applying a Gaussian disorder model to the vibrational data, the sensitivity of the method is evaluated in the presence of unwanted noises. The results confirm the robustness of the proposed study for identifying both mechanical constants and damage parameters in composite plates.

Purpose The primary purpose of this research was to expand the knowledge base regarding the behavior of steel columns during exposure to fire. This paper presents the numerical study of the effect of heat on the performance of parking steel column in a seven-story steel building under cyclic loading. Design/methodology/approach In this research, the forces and deformations developed during a fire are estimated by using detailed 3D finite-element models. The analyses are in the form of a coupled thermo-mechanical analysis in two types of loading: concurrent loading (fire and cyclic loading) and non-concurrent loading (first fire and then cyclically), and the analyses have been conducted in both states of the fire loading with cooling and without cooling using the ABAQUS software. Further, it was investigated whether, during the fire loading, the specimen was protected by a 3-cm-thick concrete coating and how much it changes the seismic performance. After verification of the specimen with the experimental test results, the column model was investigated under different loading conditions. Findings The result of analyses indicates that the effect of thermal damage on the performance of steel columns, when cooling is happening late, is more than the state in which cooling occurs immediately after the fire. In this paper, thermal–seismic performance of parking steel columns has been specified and the effect of the fire damage has been investigated for the protected steel by concrete coating and to the non-protected steel, under both cooling and non-cooling states. Originality/value This study led to recommendations based on the findings and suggestions for additional work to support performance-based fire engineering. It is clear that predicting force and deformation on steel column during fire is complex and it is affected by many variables. Here in this paper, those variables are examined and proper results have been achieved.

In some countries, collapse of bridges initiated the formal requirements for the inspection of highway bridges. Almost in all developed countries, the bridge management systems have been developed for cost-effective allocation of limited budgets for deteriorating bridges. Visual inspections are one of the most important parts of a bridge management system. On the other hand, many new and promising techniques for the non-destructive evaluation (NDE) of highway bridges have emerged in the past decades. NDT methods are costly and time consuming as well; since they cannot be used widely in bridge management systems. However, NDT methods can be used as verification of visual inspections in bridge management systems. This paper discusses visual inspections of 200 reinforced concrete bridges in Turkey and non-destructive testing applications performed on 10 bridges, which were most deficient. Penetration resistance, ultrasonic pulse velocity, rebar locating and reinforcement corrosion tests are performed on decks, piers and beams of reinforced concrete bridges and the results are compared with the results of visual inspections.

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Abstract-Cable stayed bridges are one of the most advanced bridges ever built. This type of bridges geometrically is similar to suspension bridges, but their structural behaviors are so different. In the last decade for bridges with span length (500-1000 m), the cable stayed bridges have been more welcomed. In comparison with suspension bridges, the cable stayed bridges have advantages like the simple construction of foundations. In this paper, for a specific cable stayed bridge three different connection systems including radial, harp and fan are designed and modeled by finite-element software (ANSYS). Based on the results of static analysis of bridges, the elements which have the maximum internal forces are chosen. The influence lines of shear force, axial force of cables and bending moments of selected elements are drawn for three bridge types. The results indicate that, for bridges subjected to high concentrated loads, bridges with radial and fan cables have better structural performance and for bridges subjected to high distributed loads, bridges with harp cables have better performance than the others.Index Terms-Cable-stayed bridge, influence line, ANSYS