Techno Press
Tp_Editing System.E (TES.E)
Login Search
You logged in as

scs
 
CONTENTS
Volume 53, Number 1, October 10 2024
 

Abstract
This work presents the effectiveness of differential quadrature shape functions (i.e., Lagrange interpolation polynomial, Cardinal sine function, Delta Lagrange kernel and Regularized Shannon kernel) in the solution of nonlinear vibration of multilayers piezoelectric plates with nonlinear elastic support. A piezoelectric composite laminated plate is rested on nonlinear Winkler and Visco-Pasternak elastic foundations problems. Based on 3D elasticity theory and piezoelectricity, the governing equations of motion are derived. Differential quadrature methods based on four shape functions are presented as numerical techniques for solving this problem. The perturbation method is implemented to solve the obtained nonlinear eigenvalue problem. A MATLAB code is written for each technique for solving this problem and extract the numerical results. To validate these methods, the computed results are we compare with the previous exact results. In addition, parametric analyses are offered to investigate the influence of length to thickness ratio, elastic foundation parameters, various boundary conditions, and piezoelectric layers thickness on the natural frequencies and mode shapes. Consequently, it is discovered that the obtained results via the proposed schemes can be applied in structural health monitoring.

Key Words
laminated plate; nonlinear viscoelastic foundation; perturbation; piezoelectric material; quadrature techniques; vibration

Address
Ola Ragb, Mohamed Abd Elkhalek, M.S. Matbuly, Mohamed Salah, and Tharwat Osman:Department of Engineering Mathematics and Physics, Faculty of Engineering, Zagazig University, P.O. 44519, Egypt

Mohamed Eltaher:1)Mechanical Engineering Department, Faculty of Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah, Saudi Arabia
2)Mechanical Design & Production Department, Faculty of Engineering, Zagazig University, P.O. Box 44519, Zagazig, Egypt

Abstract
In this paper, the behavior of an innovative metallic a butterfly-shaped link as damper with shear and flexural mechanism was investigated experimentally and numerically. The damper is directly attached to the diagonal member of the Concentrically Braced Frame (CBF) to prevent buckling of the braces. Since it is expected that nonlinear behavior of the system is limited to the dampers, the other parts of structures remind elastic that the damper can replaced easily after a severe earthquake. The experimental outcomes indicated that both types of dampers (with shear or flexural mechanism) pertain to stable hysteresis loops without any significant degradation in stiffness or strength. Comparing the dampers indicated that the shear damper has a greater ultimate strength (4.59 times) and stiffness (3.58 times) than flexural damper but a lower ductility (16%) and ultimate displacement (60%). Also, the shear damper has a considerable dissipation energy 14.56 times greater than flexural dampers where dissipating energy are affected by ultimate strength, stiffness and ultimate displacement. Also, based on the numerical study, the effect of main plate slenderness on the behavior of the damper was considered and the allowable slenderness was suggested to the design of the dampers. Numerical results confirmed that the flexural damper is more sensitive to the slenderness than shear damper. Accordingly, as the slenderness is less than 50 and 30, respectively, for, shear and flexural damper, no degradation in ultimate strength is realized. By increasing the slenderness, the maximum reduction of the ultimate strength, stiffness, and energy dissipation capacity reached by 16%, 7%, and 17% for SDB dampers whereas it is 3%, 33%, 20%, and 45% for MDB.

Key Words
energy; flexural mechanism; metallic damper; shear mechanism; ultimate strength

Address
Seong‐Hoon Jeong:Department of Architectural Eng, Inha University, Incheon, Republic of Korea

Ali Ghamari:Department of Civil Eng, Ilam branch, Islamic Azad University, Ilam, Iran

Reneta Kotynia:Department of Concrete Structures, Lodz University of Technology, Lodz, Poland

Abstract
This paper aims to investigate the impact of interfacial debonding on modal dynamic properties such as frequencies and vibration mode shapes. Furthermore, it seeks to identify the specific locations of debonding in rectangular concrete-filled steel tubular (CFST) columns during the subsequent stage of the study. In this study, debonding is defined as a reduction in the elasticity modulus of concrete by a depth of 3 mm at the connection point with the steel tube. Debonding leads to a lack of correlation between primary and secondary shapes of vibration modes and causes a reduction in the natural frequency in all modes. However, directly comparing changes in vibration responses does not allow for the identification of debonding locations. In this study, a novel irregularity detection index (IDI) is proposed based on modal signal processing via the 2D wavelet transform. The suggested index effectively reveals relative irregularity peaks in the form of elevations at the debonding locations. As the severity of damage increases at a specific debonding location, the relative irregularity peaks would increase only at that specific point; in other words, the detection or non-detection of a debonding location using IDI has minimal effects on the identification of other debonding locations.

Key Words
CFST columns; feature extraction; Interface debonding detection; Irregularity Detection Index (IDI); mode shape

Address
Mohtasham Khanahmadi:Faculty of Civil Engineering, Semnan University, Semnan, Iran

Borhan Mirzaei:School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran

Gholamreza Ghodrati Amiri:School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran

Majid Gholhaki:Faculty of Civil Engineering, Semnan University, Semnan, Iran

Omid Rezaifar:Faculty of Civil Engineering, Semnan University, Semnan, Iran

Abstract
Thin-walled concrete-filled U-shaped steel beams have been recently used in building structures for shortening the construction period and cost efficiency of structural members. In this study, the flexural and shear behavior of newly developed bolt-connected U-shaped steel beams filled with concrete was experimentally evaluated considering load conditions for positive and negative moments, and types of U-shaped steel sections. Because the cross sections are not symmetrical about a horizontal axis, compressive buckling of bottom plates was observed along with web shear buckling under negative moment loading, while the slab concrete under compression was crushed under a positive moment loading. Despite such different shear failure modes depending on load conditions, the shear strength of the composite beams can be conservatively predicted using AISC 360-16 and Eurocode 4. Although the shear contribution of filled concrete is neglected according to the current design codes, the shear capacity of the steel web considering the shear buckling coefficient corresponding to the web width-to-thickness ratio reasonably predicts the test results. In addition, for deep composite beams, the longitudinal lips of a U-shaped steel section anchored into filled concrete can improve the interfacial bond between steel and concrete, thereby enhancing the shear contribution of the steel web.

Key Words
bending and shear strength; bolted connection; cold-formed steel; composite structures; structural design

Address
Chul-Goo Kim: Department of Architectural and Urban Systems Engineering, Ewha Womans University, Seoul, 03760, Republic of Korea

Sang-Hyun Lee: School of Architecture, Dankook University, Yongin-si, Gyeonggi-do, 16890, Republic of Korea


Abstract
This paper focuses on trigonometric porosity distribution to analyze its effect on the free vibration frequencies of porous orthotropic multi-layered composite plates. Three types of porosity distributions are considered. The governing equations of the free vibration response of porous orthotropic multi-layered composite plates are derived from the Hamilton's principle using higher-order shear deformation theory. The free vibration frequency relation of the problem is obtained by performing Galerkin's method. After the validation process of the relation under the available literature, a few parametric analyses are performed to observe the influence of shear deformation, porosity distribution, orthotropy, layer sequence, and different geometric properties on the frequencies.

Key Words
free vibration; laminated composite; orthotropy; porosity; porous plate; shear deformation theory

Address
Ferruh Turan:Department of Civil Engineering, Faculty of Engineering, Ondokuz May

Abstract
A cost-effective fabrication method suitable for research purposes is proposed in this study. The elastic modulus of the fabricated functionally graded materials is evaluated and compared using two experimental methods: the three-point bending test and the tensile test, with a focus on the fiber volume fraction of the FGM layers. New methods for computing the elastic modulus are introduced, which are based on Castigliano's theorem and the secant modulus concept, incorporating the non-linear behavior of the material. Additionally, the mode I fracture toughness of the FGM layers is measured accurately using the threepoint bending test and finite element analysis, and the influence of varying fiber volume fractions on this parameter is investigated through statistical analysis. Results indicate that while an increase in fiber volume fraction correlates with a rise in elastic modulus, it does not necessarily lead to an enhancement in mode I fracture toughness, highlighting the complex interactions between material composition and mechanical properties.

Key Words
crack; elastic modulus; fracture toughness; Functionally Graded Materials (FGMs); tensile tests; three-point bending

Address
Sayed Mohammad Hossein Izadi, Mahdi Fakoor and Babak Mirzavand:College of Interdisciplinary Science and Technology, University of Tehran, Tehran, Iran

Abstract
This study proposes a new hybrid approach that utilizes post-earthquake survey data and numerical analysis results from an evolving finite element routing model to capture vulnerability processes. In order to achieve cost-effective evaluation and optimization, this study introduced an online data evolution data platform. The proposed method consists of four stages: 1) development of diagnostic sensitivity curve; 2) determination of probability distribution parameters of throughput threshold through optimization; 3) update of distribution parameters using smart evolution method; 4) derivation of updated diffusion parameters. Produce a blending curve. The analytical curves were initially obtained based on a finite element model used to represent a similar RC building with an estimated (previous) capacity height in the damaged area. The previous data are updated based on the estimated empirical failure probabilities from the post-earthquake survey data, and the mixed sensitivity curve is constructed using the update (subsequent) that best describes the empirical failure probabilities. The results show that the earthquake rupture estimate is close to the empirical rupture probability and corresponds very accurately to the real engineering online practical analysis. The objectives of this paper are to obtain adequate, safe and affordable housing and basic services, promote inclusive and sustainable urbanization and participation, implement sustainable and disaster-resilient buildings, sustainable human settlement planning and management. Therefore, with the continuous development of artificial intelligence and management strategy, this goal is expected to be achieved in the near future.

Key Words
AI data thresholds; FEM programs; fuzzy models; mixed algorithm of evolution; post-earthquake estimation; resilient and sustainable infrastructures; seismic activity

Address
ZY Chen:School of Science, Guangdong University of Petrochemical Technology, Maoming, Guangdong, China

Yahui Meng:School of Science, Guangdong University of Petrochemical Technology, Maoming, Guangdong, China

Huakun Wu:School of Computer Science, Guangdong Polytechnic Normal University, Guangzhou, Guangdong, China

ZY Gu:School of Science, Guangdong University of Petrochemical Technology, Maoming, Guangdong, China

Timothy Chen:Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA

Abstract
The present paper deals with a comprehensive study about dynamic performance and educational economic assessment of nanocomposite structures, while it focuses on truncated conical shells. Advanced structure dynamic behavior has been analyzed by means of AI techniques, which allow one to predict and optimize their performances with good accuracy for different loading and environmental conditions. The incorporation of the AI method significantly enhances the computational efficiency and is a powerful tool in designing nanocomposites and for their structural analysis. Further, an educational assessment is provided in the context of cost and practicality related to such structures in engineering education. This study showcases the capabilities of AI-enabled methods with regard to cost reduction, improvement of structural efficiency, and enhancement of learning engagement for students through certain practical examples on state-of-the-art nanocomposite technology. The results also confirm a remarkable capability of artificial intelligence regarding the optimization of both dynamic and economic aspects, which could be highly valued for further development of nanocomposite structures.

Key Words
artificial intelligence techniques; dynamic performance; educational; nanocomposite structures

Address
Han Zengxia:Department of Education, Xinzhou Teachers

Techno-Press: Publishers of international journals and conference proceedings.       Copyright © 2025 Techno-Press ALL RIGHTS RESERVED.
P.O. Box 33, Yuseong, Daejeon 34186 Korea, Email: admin@techno-press.com