HCMCOU Journal of Science – Advances in Computational Structures

An Efficient Computational System For Defect Prediction through Neural Network And Bio-inspired Algorithms

2024-07-30T11:31:21+07:00

Detecting and locating damage is essential in maintaining structural integrity. While Artificial Neural Networks (ANNs) are effective for this purpose, their performance can be significantly improved through advanced optimization techniques. This study introduces a novel approach using the Grasshopper Optimization Algorithm (GOA) to enhance ANN capabilities for predicting defect aluminum plates. The methodology begins by deriving input parameters from natural frequencies, with defect locations as the output. A Finite Element Model (FEM) is used to simulate data by varying defect locations, creating a comprehensive dataset. To validate this approach, experimental data from vibration analyses of plates with different defect locations is collected. We then compare the performance of our GOA-optimized ANN against other metaheuristic algorithms, such as Cuckoo Search Algorithm (CSA), Bat Algorithm (BA), and Firefly Algorithm (FA). Notably, CSA's performance is slightly close to GOA. The results show that our GOA-based method outperforms these traditional algorithms, demonstrating superior accuracy in damage prediction. This advancement holds significant potential for applications in structural integrity monitoring and maintenance.

2D and 3D seismic damage analysis of concrete gravity dam

2024-06-20T22:23:04+07:00

This study focuses on the 2D and 3D nonlinear seismic damage analysis of a proposed concrete gravity dam using the finite element program ABAQUS, employing the concrete damaged plasticity model. To compare the 2D and 3D analyses, four different cases of the dam's spillway section are simulated. Initially, a frequency analysis is performed to estimate the damping parameter. Subsequently, seismic analysis is conducted using simulated ground acceleration motion. The time history of relative displacement between the crest and base of the dam is recorded, and the maximum values and their occurrence times are compared. Additionally, the tensile damage distributions over the dam at specific time instants during the ground motion period are analyzed to examine the initiation and evolution of the damage. The results indicate that while the plane-stress assumption yields similar outcomes in terms of maximum relative displacement and final damage distribution when compared to the 3D analysis, there are notable differences in natural frequency and the timing of the first crack, second crack, and maximum relative displacement.

Decision-making in structural engineering using BHARAT-II method

2024-07-30T10:24:54+07:00

This paper presents a simple and effective multi-attribute decision-making method, named as BHARAT-II (Best Holistic Adaptable Ranking of Attributes Technique - II), to choose the best alternatives for different structural engineering related problems. Two case studies are presented to demonstrate the proposed multi-attribute decision-making method. The first case study addresses the problem of (a). selecting the best construction method for a bridge out of 4 available methods considering 7 selection attributes, (b). selecting best structural system of bridge out of 7 structural systems considering 11 selection attributes, and (c). selecting best construction material out of 4 materials considering 4 selection attributes; the second case study addresses the problem of selecting the best structural system of a housing project by considering 4 alternative structural systems and 5 selection attributes (i.e., criteria) involving 19 sub-attributes (sub-criteria). The results of the proposed BHARAT-II decision-making method are compared with those of other well-known multi-attribute decision-making methods. The proposed method is shown to be simple to implement, providing a logical way for allocating weights to the selection attributes and adaptable to solve the best alternative selection problems of structural engineering.

Damage detection of beam-like structures using a combination of wavelet transform and subtraction of intact and damaged mode shapes

2024-06-10T09:59:30+07:00

Detection of damages with low levels has been one of the most critical challenges. As a result, many damage detection methods cannot detect damages or cracks with a level lower than 10%. On-surface damages as low-level damages are challenging to localize. A new technique is proposed to eliminate this challenge based on wavelet transformation of the difference in damaged and intact mode shapes. In this way, a finite element model is developed for obtaining governing equations of thin beams. The developed finite element model provides the mode shape signals. Then, the signals are decomposed by wavelet transform. The findings of this study show that in both numerical and experimental investigations, the proposed method is very efficient since the proposed method can detect on-surface damages having a level below 10%.

In-Plane and Out-of-Plane Bending Vibration Analysis of the Laminated Composite Beams Using Higher-Order Theories

2024-05-29T10:51:54+07:00

In this paper, higher-order shear deformation theories for a thorough analysis of the in-plane and out-of-plane vibrational characteristics of laminated composite beams have been presented. Through the introduction of new displacement fields and the consideration of rotary inertia and Poisson's effect, the kinetic and potential energies of the beams have been derived. This formulation, displaying significant generality, accommodates arbitrary stacking sequences. Utilizing the finite element method, a new element has been presented for calculating the beam's vibrational characteristics. Featuring three nodes, each with seven degrees of freedom, this higher-order element provides a detailed representation of complex behaviors. Mass and stiffness matrices have been derived using the energy method and apply boundary conditions through the penalty approach. The results exhibit a high degree of consistency and alignment with those obtained from the 3D commercial software ANSYS, validating the accuracy and reliability of the proposed methodology for structural analysis. This comprehensive approach contributes to advancing the understanding and modeling of laminated composite beams in diverse engineering applications. The effects of different parameters on the in-plane and out-of-plane vibration analysis of laminated composite beams have been investigated in detail.