Abstract
This study investigates the thermoelastic behavior of thick-walled truncated conical shells with a constant middle radius and linearly varying thickness under mechanical loading and bi-directional thermal gradients. The governing equations are formulated using First-Order Shear Deformation Theory (FSDT) combined with First-Order Temperature Theory (FTT), and are solved semi-analytically using the disk-form multilayer method (MLM). The analytical results are validated by finite element simulations, which show excellent agreement in radial displacement and stress distributions. Parametric analyses indicate that radial displacement and equivalent stress increase along the shell length and become more pronounced at higher angular velocities, while shear stresses remain negligible. These results provide valuable insights into the thermoelastic response of rotating conical pressure vessels and similar hightemperature structural components.
Abstract
Excessive extraction of river sand has led to the depletion of natural sand reserves and causes environmental problems in limited riverbeds. Consequently, there has been sustained interest in identifying alternatives to river sand for concrete production. Crushed sand, in this context, is considered as a feasible substitute for natural river sand. In this study, the performance of concrete produced with river sand and crushed stone sand is evaluated. Specifically, the compressive, tensile, and flexural strengths of concrete were examined at different watercement (w/c) ratios: 0.45, 0.5, and 0.6. Additionally, the resistance of concrete to freeze-thaw cycles was assessed for both types of sand. The results indicate that concretes produced with river sand and crushed sand exhibit similar trends with changes in w/c ratio. More precisely, the compressive strength increased from 25.69 to 30.21 MPa for crushed sand concrete and from 19.78 to 33.65 MPa for river sand concrete as the w/c ratio decreased from 0.6 to 0.5. Moreover, concrete with crushed stone sand showed higher splitting tensile strength than that with river sand, as well as superior resistance to freeze-thaw cycles. Finally, the flexural strengths of concrete beams containing either river sand or crushed sand decreased similarly with increasing w/c ratio.
Key Words
concrete compounds; crushed stone sand; mechanical properties of concrete; river sand
Address
Fidan Güzel: Department of Civil Engineering, Faculty of Engineering, Igdir University, Igdir 76000, Türkiye
Yunus Dere: Department of Civil Engineering, Faculty of Engineering, Necmettin Erbakan University, Konya 42000, Türkiye
Yasin Onuralp Özkiliç: Department of Technical Sciences, Western Caspian University, Baku, 1001, Azerbaijan
Abstract
This article investigates the structural analysis and design of offshore wind turbine (OWT) support structures using both traditional and suction piles under soil liquefaction. A finite element model centered on a single suction pile was first generated to evaluate depth-dependent excess pore water pressure (EPWP) ratios near and away from the pile under liquefaction conditions. Findings reveal that suction piles exhibit substantial internal resistance to soil liquefaction, as shown by lower EPWP ratios inside the pile, which enhances soil stability and shear capacity. This resistance diminishes with distance from the pile, highlighting the stabilizing role of confined soil and water within the pile. Using depth-dependent EPWP ratios, the study establishes envelope curves for suction and traditional piles to adjust soil spring stiffness during liquefaction, aiding in structural analyses under diverse design load cases (DLCs) for OWT support structures. Results indicate that liquefaction-related conditions are not the primary factor influencing steel usage; rather, non-liquefaction DLCs govern design demands. Additionally, suction piles often require more steel than traditional piles due to installation pressures, though they remain competitive in deep waters. Settlement and tilting issues, particularly in liquefiable soils, underscore the need for careful design of suction piles on sandy seabeds.
Key Words
earthquake; excess pore water pressure; finite element analysis; offshore wind turbine; soil liquefaction; structural steel design; suction pile
Address
Shen-Haw Ju, Chen-Yeh Liu: Department of Civil Engineering, National Cheng-Kung University, Tainan, 70101, Taiwan
Abstract
This paper presents an analytical investigation of the reflection and transmission of elastic waves at an imperfect interface separating an elastic half-space and a bio-thermo-diffusive viscoelastic half-space, with particular emphasis on the role of temperature-dependent thermal conductivity. Unlike conventional interface-wave models that assume constant thermal conductivity, the present formulation incorporates variable thermal conductivity into the bioheat equation, leading to a more physically realistic description of thermo-mechanical coupling in viscoelastic media. The resulting nonlinearity is treated analytically using the Kirchhoff transformation, allowing closed-form normal-mode solutions to be obtained. Reflection and transmission coefficients, together with the associated energy ratios, are derived for both longitudinal (P) and shear vertical (SV) wave incidences by enforcing mechanical, thermal, and diffusive boundary conditions at a mechanically imperfect interface. Numerical results demonstrate that variable thermal conductivity significantly alters wave attenuation and energy redistribution by enhancing thermodiffusive coupling, particularly near critical angles of incidence. Blood perfusion is shown to act as an additional damping mechanism that suppresses oscillatory energy exchange and accelerates energy dissipation, with these effects being markedly amplified in the presence of viscoelasticity. Furthermore, SV-wave incidence exhibits higher sensitivity to thermal conductivity variations and perfusion effects than P-wave incidence, reflecting stronger coupling between shear deformation and thermo-diffusive processes. The proposed model extends existing thermoelastic and viscoelastic interface theories and provides new insight into energy partition mechanisms in coupled thermo-diffusive viscoelastic media.
Key Words
energy ratios; imperfect interface; reflection and transmission; thermo-diffusive coupling; variable thermal conductivity; viscoelastic waves
Address
Amr M.Y. Abdelaty: Department of Basic Sciences, Common First Year Deanship, King Saud University, P.O. Box 1142, Riyadh 12373, Saudi Arabia
Khaled Lotfy: Department of Mathematics, Faculty of Science, Zagazig University, P.O. Box 44519, Zagazig, Egypt
Saurav Sharma: Cullen College of Engineering, University of Houston, 7900 Cambridge Street, #7-2G, Houston, Texas, 77054, USA
Rajneesh Kumar: Department of Mathematics, Kurukshetra University, Kurukshetra, 136119, Haryana, India
Fulin Shang: Department of Engineering Mechanics, Xi'an Jiaotong University, Xian-Ning West Road 28, Xi'an, 710049, China
Alaa A. El-Bary: Arab Academy for Science, Technology and Maritime Transport, P.O. Box 1029, Alexandria, Egypt
Lotfi Jlali: Department of Mathematics and Statistics, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11432, Saudi Arabia
Ibrahim S. Elshazly: Department of Basic Sciences, Common First Year Deanship, King Saud University, P.O. Box 1142, Riyadh 12373, Saudi Arabia
Abstract
Plenty of existing studies focus on damage detection of simpler structures using MATLAB environment; however, modeling of full-scale structures is not applicable only using this software. Hence, the focus of this research is to identify damage in symmetric full-scale structures by means of SAP2000-OAPI feature for generating a connection between SAP2000 software and MATLAB to achieve a two-way data exchange path. A novel objective function is proposed using the combination of natural frequencies and modal assurance criterion (MAC) for generalized flexibility matrix (GFM) of the monitored structure and its numerical model, taking advantage of reducing the effect of modal data of higher vibration modes and overcoming non-unique answers. Equilibrium Optimizer (EO) has been employed for the optimization process. Two numerical examples comprising a full-scale symmetric industrial steel frame and a 3D two-story building are examined under two damage patterns. The results have shown that suggested technique is capable of identifying structural damage in both examples with high level of accuracy even using noisy limited modal data. Moreover, the performance of EO has been compared to that of Grey Wolf Optimizer (GWO) and Whale Optimization Algorithm (WOA), the results of which signify the superior performance of EO over other algorithms.
Key Words
Equilibrium Optimizer (EO); FE model updating; Generalized flexibility matrix (GFM); SAP2000-OAPI feature; structural damage detection
Address
Reza Aghajani, Omid Azizpour Miandoab, Ashkan Khodabandehlou: Department of Civil Engineering, Ur.C., Islamic Azad University, Urmia, Iran
Seyed Sina Kourehli: Department of Civil Engineering, Azarbaijan Shahid Madani University, Tabriz, Iran
Abstract
Plenty of existing studies focus on damage detection of simpler structures using MATLAB environment; however, modeling of full-scale structures is not applicable only using this software. Hence, the focus of this research is to identify damage in symmetric full-scale structures by means of SAP2000-OAPI feature for generating a connection between SAP2000 software and MATLAB to achieve a two-way data exchange path. A novel objective function is proposed using the combination of natural frequencies and modal assurance criterion (MAC) for generalized flexibility matrix (GFM) of the monitored structure and its numerical model, taking advantage of reducing the effect of modal data of higher vibration modes and overcoming non-unique answers. Equilibrium Optimizer (EO) has been employed for the optimization process. Two numerical examples comprising a full-scale symmetric industrial steel frame and a 3D two-story building are examined under two damage patterns. The results have shown that suggested technique is capable of identifying structural damage in both examples with high level of accuracy even using noisy limited modal data. Moreover, the performance of EO has been compared to that of Grey Wolf Optimizer (GWO) and Whale Optimization Algorithm (WOA), the results of which signify the superior performance of EO over other algorithms.
Key Words
Equilibrium Optimizer (EO); FE model updating; Generalized flexibility matrix (GFM); SAP2000-OAPI feature; structural damage detection
Address
Reza Aghajani, Omid Azizpour Miandoab, Ashkan Khodabandehlou: Department of Civil Engineering, Ur.C., Islamic Azad University, Urmia, Iran
Seyed Sina Kourehli: Department of Civil Engineering, Azarbaijan Shahid Madani University, Tabriz, Iran
Abstract
Evaluating the impact resistance of ferrocement channels is essential for their application in low-cost roofing and similar structural components. This study investigates the impact response and crack propagation behaviour of unreinforced and steel fibre-reinforced ferrocement channels subjected to repeated drop-weight impact loading. Impact performance was assessed in terms of energy at first cracking and failure, post-crack resistance, ductility, and crack width evolution. Experimental results demonstrated that steel fibre reinforcement significantly enhanced impact toughness, with approximately 2.4-fold increase at first crack and nearly 4-fold increase at failure, and increased the impact ductility index by about 70%, indicating a clear transition from brittle to ductile behaviour. Fibre inclusion also reduced crack width by up to 68% and maintained narrow crack openings under repeated impacts. A numerical parametric study showed that steel fibres enhanced impact energy absorption by 7.6-14.9% depending on the number of welded mesh layers, while increasing mesh layers beyond two offered marginal benefits. Randomly oriented fibres exhibited higher impact toughness than planar orientation, with improvements of up to 37%. Overall, two layers of welded mesh were found to provide optimal impact resistance, irrespective of fibre presence.
Key Words
ANSYS explicit dynamics; drop weight test; ferrocement; impact behaviour; numerical modelling; steel fibre
Address
V. Radhika: Department of Civil Engineering, Sri Sivasubramaniya Nadar College of Engineering, Kalavakkam 603110, India
Karthika Soman, P.T. Nowshaja: Department of Civil Engineering, Government Engineering College, Thrissur, 680009, India
