Damage identification of a 2D frame structure using two-stage approach

Seyed Rohollah Hoseini Vaez,Narges Fallah 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.3

In this article, a two-stage damage identification approach is employed to detect the site and extent of multiple damage cases in a 2D frame structure. In the first stage, Damage locating vector (DLV) method based on a new indicator called EDS (Exponential decreased stress) is applied to localize the damaged elements. Next, the damage extents of suspected elements are quantified using two metaheuristic algorithms, Water evaporation optimization (WEO) and accelerated WEO. Numerical example consists of a 2D frame structure with two types of meshing elements, 35 and 105 frame elements. For every state, two multiple damage cases are tested in noisy condition. To compare performance of the two-stage method with one-stage optimization method, the studied cases are also run using these two metaheuristic algorithms. The results indicate that the two-stage approach is more effective than one-stage because the number of intact element detected as damaged one and computational errors for actual damaged elements in one-stage method are more while the two-stage approach spends a much shorter time.

Reliability-Based Optimization of One-Bay 2-D Steel Frame

Seyed Rohollah Hoseini Vaez,Saeid Sarvdalir 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.7

In the conventional method of designing structures, a number of constants often characterize decisive parameters such asdimensions, material strengths and loads. Insufficient precision in modeling and implementing the structures are among theuncertainties that exist in structural design. If the maximum safety is expected for a structure, a combination of optimization andreliability should be used; this means that the structure should be optimized on the basis of reliability rather than economicconsiderations. In this study, geometry optimization of different steel frames has been done based on reliability; in fact, the objectiveis to obtain dimensions which are expected to have the best performance in terms of safety. To do so, different failure surfaces shouldfirstly be defined and the structure should be optimized on the basis of the maximum reliability possible. The answer to the problemis the maximum distance from the defined failure surface obtained by probabilistic method. Also, decision-making analysis, which isthe principle of engineering judgment, has been defined in the mathematical model so that the structural engineer has more options todetermine the type of structural performance. The solution of linear and non-linear problems can be determined by implementing thealgorithm for several times. Genetic algorithm can obtain the design point and probability of failure in statistical problems; therefore,it has been used to find the best dimensions of the frame under study.

Simplified dolphin echolocation algorithm for optimum design of frame

Ali Kaveh,Seyed Rohollah Hoseini Vaez,Pedram Hosseini 국제구조공학회 2018 Smart Structures and Systems, An International Jou Vol.21 No.3

Simplified Dolphin Echolocation (SDE) algorithm is a recently developed meta-heuristic algorithm. This algorithm is an improved and simplified version of the Dolphin Echolocation Optimization (DEO) method, based on the baiting behavior of the dolphins. The main advantage of the SDE algorithm is that it needs no empirical parameter. In this paper, the SDE algorithm is applied for optimization of three well-studied frame structures. The designs are then compared with those of other meta-heuristic methods from the literature. Numerical results show the efficiency of the SDE algorithm and its competitive ability with other well-established meta-heuristics methods.

Detection of damage in truss structures using Simplified Dolphin Echolocation algorithm based on modal data

Ali Kaveh,Seyed Rohollah Hoseini Vaez,Pedram Hosseini,Narges Fallah 국제구조공학회 2016 Smart Structures and Systems, An International Jou Vol.18 No.5

Nowadays, there are two classes of methods for damage detection in structures consisting of static and dynamic. The dynamic methods are based on studying the changes in structure\'s dynamic characteristics. The theoretical basis of this method is that damage causes changes in dynamic characteristics of structures. The dynamic methods are divided into two categories: signal based and modal based. The modal based methods utilize the modal properties consisting of natural frequencies, modal damping and mode shapes. As the modal properties are sensitive to changes in the structure, these can be used for detecting the damages. In this study, using dynamic method and modal based approach (natural frequencies and mode shapes), the objective function is formulated. Then, detection of damages of truss structures is addressed by using Simplified Dolphin Echolocation algorithm and solving inverse optimization problem. Many scenarios are used to simulate the damages. To demonstrate the ability of the algorithm, different truss structures with several multiple elements scenarios are tested using a few runs. The influence of the two different levels of noise in the modal data for these scenarios is also considered. The last example of this article is investigated using a different mutation. This mutation obtains the exact answer with fewer loops and population by limited computational effort.

Damage identification in laminated composite plates using a new multi-step approach

Narges Fallah,Seyed Rohollah Hoseini Vaez,Hossein Fasihi 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.29 No.1

In this paper a new multi-step damage detection approach is provided. In the first step, condensed modal residual vector based indicator (CMRVBI) has been proposed to locate the suspected damaged elements of structures that have rotational degrees of freedom (DOFs). The CMRVBI is a new indicator that uses only translational DOFs of the structures to localize damaged elements. In the next step, salp swarm algorithm is applied to quantify damage severity of the suspected damaged elements. In order to assess the performance of the proposed approach, a numerical example including a three-layer square laminated composite plate is studied. The numerical results demonstrated that the proposed CMRVBI is effective for locating damage, regardless of the effect of noise. The efficiency of proposed approach is also compared during both steps. The results demonstrate that in noisy condition, the damage identification approach is capable for the studied structure.

Simplified dolphin echolocation algorithm for optimum design of frame

Kaveh, Ali,Vaez, Seyed Rohollah Hoseini,Hosseini, Pedram Techno-Press 2018 Smart Structures and Systems, An International Jou Vol.21 No.3

Simplified Dolphin Echolocation (SDE) algorithm is a recently developed meta-heuristic algorithm. This algorithm is an improved and simplified version of the Dolphin Echolocation Optimization (DEO) method, based on the baiting behavior of the dolphins. The main advantage of the SDE algorithm is that it needs no empirical parameter. In this paper, the SDE algorithm is applied for optimization of three well-studied frame structures. The designs are then compared with those of other meta-heuristic methods from the literature. Numerical results show the efficiency of the SDE algorithm and its competitive ability with other well-established meta-heuristics methods.

Probabilistic performance-based optimal design of low-rise eccentrically braced frames considering the connection types

Mohammad Ali Fathali,Seyed Rohollah Hoseini Vaez 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.46 No.5

In this study, the weight and the connections type layout of low-rise eccentrically braced frame (EBF) have been optimized based on performance-based design method. For this purpose, two objective functions were defined based on two different aspects on rigid connections, in one of which minimization and in the other one, maximization of the number of rigid connections was considered. These two objective functions seek to increase the area under the pushover curve, in addition to the reduction of the weight and selection of the optimum connections type layout. The performance of these objective functions was investigated in optimal design of a three-story eccentrically braced frame, using two meta-heuristic algorithms: Enhanced Colliding Bodies Optimization (ECBO) and Enhanced Vibrating Particles System (EVPS). Then, the reliability indices of the optimal designs for both objective functions were calculated for the story lateral drift limits using Monte-Carlo Simulation (MCS) method. Based on the reliability assessment results of the optimal designs and taking the three levels of safety into account, the final designs were selected and their specifications were compared.