Abstract
Functionally graded materials (FGMs) have gained substantial attention from researchers due to their exceptional strength and thermal resistance. Their utilization in the aviation and automobile industries has significantly improved the efficiency of various structural components. Moreover, stiffened panels find wide applications in aerospace and automobile structures and these panels are frequently exposed to extreme environments. It is from this perspective that our research is focused on analysing the vibroacoustic response of stiffened functionally graded panels subjected to external dynamic excitations in a thermal environment. In the present research work, a finite element model is developed to conduct the dynamic analysis of functionally graded stiffened panels using the first-order shear deformation theory. Subsequently, a boundary element based model is also developed and coupled with the finite element model to investigate the sound radiation behaviour of those
panels in a thermal environment. The material properties of FG stiffened panels are considered as temperature dependent, while the thermal environment is assumed to be acting as linearly varying through the panel's thickness. The present investigation aim to compare the vibroacoustic responses of different panels due to stiffener orientations, material compositions, power law indices and plate thicknesses at various temperatures. The research findings highlight the significant impact of addition of stiffeners, its orientation and material compositions on the sound radiation characteristics of these panels under thermal environments. The present numerical model can easily be employed for analysing the sound radiation behaviour of other types of flat or curved stiffened panels having arbitrary geometry and boundary conditions.
Address
Ashish K. Singh, Anwesha Pal: Department of Civil Engineering, National Institute of Technology Silchar, Silchar 788010, India
Shashi Kumar: IMEG Engineering India Pvt Ltd., India
Anuja Roy: Department of Construction Engineering (Salt Lake Campus), Jadavpur University, Kolkata 700032, India
Atanu Sahu: Department of Civil Engineering, National Institute of Technology Silchar, Silchar 788010, India
Abstract
In this study, the optimization of the composite floor system with cellular beams is investigated. The objective function is the minimization of carbon dioxide (CO2) emissions and the optimal solution is defined by 19 design variables for the beam's topology, beams fabricated process, steel deck characteristics, columns. The requirements of the ultimate and serviceability state limits are considered for the composite floor system design. The program is developed within the MATLAB platform. A number of the benchmark test problems of composite floor systems with full web beams are optimized with cellular beams to verify the reduction of total CO2 emission. The optimum results are obtained by Particle Swarm Optimization (PSO), Genetic Algorithm (GA) and Bonobo Algorithm (BO). A comparison of the performance of these algorithms shows that the BO algorithm has a higher search capability and results in better solutions than PSO and GA algorithms in the optimization of the composite floor system with the cellular beams and the use of cellular beams can reduce the total CO2 emissions of the floor above 20%.
Key Words
CO2 emission; composite floor system with cellular beams; metaheuristic algorithms; optimization
Address
Gabrieli Fontes Silva: Department of Civil Engineering, Federal University of Espirito Santo, Av. Fernando Ferrari, 514, Goiabeiras, Vitória, Espírito Santo, Brazil
Moacir Kripka: Civil Engineering Graduate Program, Federal University of Technology–Paraná, Via do Conhecimento, Km 1, Pato Branco 85503-390, Paraná, Brazil
Élcio Cassimiro Alves: Department of Civil Engineering, Federal University of Espirito Santo, Av. Fernando Ferrari, 514, Goiabeiras, Vitória, Espírito Santo, Brazil
Abstract
Manufacturing industries, now-a-days, focus mostly on redesigning of the products for reducing cost and lead-time via detailed analysis of its composition and constructional design regarded as the Reverse Engineering (RE) process that involves the acquisition of relevant data of the original product, analysis for its functional use and finally, reproduction of the design for improving the functionality. In the present work, a new model based on optimization at different steps of RE, is proposed to redesign a structural component, which is subjected to severe tensile stress while in service. The component under study is an accessory namely, hitch bracket, attached to the rear axle of a tractor to connect it to the plough. The methodology includes building of a 3D Computer Aided Design (CAD) model from the scanned data of the existing component with the help of 3D scanner. Computer Aided Engineering (CAE) analysis is carried out on the CAD model with existing load conditions by Finite Element Analysis (FEA). Topological optimization is carried out giving rise to a modified/optimized design of the component. It is observed that the performance of the modified component improves significantly with simultaneous weight reduction without affecting its functional use and the manufacturing process setup.
Address
Dilip K. Sahu, Priyam P. Tripathy, Trupti R. Mahapatra, Debadutta Mishra: Department of Production Engineering, Veer Surendra Sai University of Technology, Burla, Odisha, 768018, India
Punyapriya Mishra: Department of Mechanical Engineering, Veer Surendra Sai University of Technology, Burla, Odisha, 768018, India
Abstract
The cracking mechanism in ceramsite aerated concrete block (CACB) infill walls were studied in low seismic
fortification intensity coastal areas with frequent occurrence of typhoons. The inter-story drifts of an eight-story residential building under wind loads and a seismic fortification intensity of six degrees were analyzed by using the PKPM software. The maximum inter-story drift ratio of the structure in wind load was found to be comparable to that under the seismic fortification intensity of six degrees. However, when accounting for the large gust wind speed of typhoon, the maximum inter-story drift ratio
was much larger than that obtained under reference wind load. In addition, the finite element models of RC frames were employed by displacement loading to simulate two scenarios with and without window hole in the CACB infill walls, respectively. The simulation results show no signs of cracking in both the infill walls with window hole and those without window for the inter-story drift caused by seismic loads and the reference wind load. However, both types of infill walls experienced structural creaking when assessing the gust wind pressure recorded from previous typhoon monitoring. It is concluded that an underestimate of wind loads may contribute substantially to the cracking of frame CACB infill walls in low seismic fortification intensity coastal areas. Consequently, it is imperative to adopt wind pressure values derived from gust wind speeds in the design of CACB infill walls within frame structures. Finally, the future research directions of avoiding cracks in CACB filled walls were proposed. They were the material performance improving and building structure optimizing.
Address
Ruige Li, Yu Gao, Hongjian Lin: School of Civil Engineering and Architecture, Taizhou University, Taizhou Jiaojiang, 318000, China
Mingfeng Huang: School of Civil Engineering & Architecture, Zhejiang University, Hangzhou,310058, China
Chenghui Wang: Taizhou Institute of Planning and Design for Urban and Rural, Taizhou Jiaojiang, 318000, China
Zhongzhi Hu: School of Civil Engineering and Architecture, Taizhou University, Taizhou Jiaojiang, 318000, China
Lingyi Jin: Zhedong Engineering Investigation Institute, Taizhou Linhai, 317000, China
Abstract
This study evaluates the seismic performance of a premodern six story reinforced concrete building typology designed during the communism period of Albania and build throughout the country. During the November 26, 2019 Earthquake in Albania, the most affected reinforced concrete buildings were among the old templates, lacking shear walls and inadequate reinforcement details which suffer from concrete aging. The mathematical model of the selected building is done in the environments of ZeusNL software, developed especially for earthquake engineering applications. The capacity curve of the structure is gained using the conventional static nonlinear analysis. On the other hand, the demand estimation is utilized using one of the recent methods known as Incremental Dynamic Analysis with a set of 18 ground motion records. The limit states in both curves are defined based on the modern guidelines. For the pushover, immediate occupancy (IO), life safety (LS) and collapse prevention (CP) are plotted in the same graph with capacity curve. Furthermore, on each IDA derived, the IO, CP and global instability (GI) are determined. Moreover, the IDA fractiles are generated as suggested by the literature, 16%, 50% (median) and 84%. In addition, the comparative assessment of the IDA median with capacity curve shows good correlation points. Lastly, this study shows the approach of determination of LS in IDA fractiles for further vulnerability assessment based on the local seismic hazard map with 95 and 475 return period.
Key Words
incremental dynamic analysis; November 26, 2019 Albanian Earthquake; premodern RC building typology; pushover analysis; seismic performance assessment; ZeusNL
Address
Marsed Leti and Hüseyin Bilgin: Department of Civil Engineering, Faculty of Architecture and Engineering, EPOKA University, Tirana, Albania
Abstract
Since the cost of reconstruction is very high and the structure may have been damaged by an earthquake, we must
retrofit the structure. Therefore, the importance of studying this issue is very high in order to achieve the desired resistance against the regulations. The present study involved the numerical and experimental analysis of nine concrete frames, consisting of three concrete frames, three concrete frames with bracing, and three concrete frames with a TADAS damper. The purpose of this study is to strengthen the damaged concrete frame using braces and TADAS dampers. Observations were made of the frames as they were subjected to controlled displacement. Also, ABAQUS software was used to compare numerical and experimental results. According to the results, the software was sufficiently capable of modeling the studied frames. Additionally, a parametric study was conducted on the thickness and number of bending plates. Thickness increases from 8 mm to 12 mm, 8 mm to 15 mm, and 8 mm to 20 mm, increasing the base shear by about 6.7%, 11.1%, and 25%, respectively. Furthermore, increasing the number of plates from 4 to 5, 4 to 6, and 4 to 7 increased base shears by about 4.5%, 8.4%, and 14%, respectively.
Key Words
concrete frames; cycle loading; damper ADAS; ductility
Address
Reza Nazeran: Civil Engineering Department, Semnan Branch, Islamic Azad University, Semnan, Iran
Ali Hemmati: Seismic Geotechnical and High Performance Concrete Research Centre, Civil Engineering Department, Islamic Azad University, Semnan Branch, Semnan, Iran
Hasan Haji Kazemi: Department of Civil Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
Abstract
An explosion from a specific source can generate high pressure, causing damage to structures and people in and around them. For the design of protective structures, although explosion overpressure is considered the main loading parameter, parts are only considered using standard design procedures, excluding special installations. Properties of the explosive, such as molecular structure, shape, dimensional properties, and the physical state of the charge, determine the results in a high-grade or low-grade explosion. In this context, it is very important to determine the explosion behaviors of the structures and to take precautions against these behaviors. Especially structures in areas with high explosion risk should be prepared for blast loads. In this study, the behavior of non-anchored blast resistant modular buildings was investigated. In the study, analyzes were carried out for cases where modular buildings were first positioned on a reinforced concrete surface and then directly on the ground. For these two cases, the behavior of the modular structure placed on the reinforced concrete floor against burst loads was evaluated with Stribeck curves. The behavior of the modular building placed directly on the ground is examined with the Pais and Kausel equations, which consider the structure-ground interaction. In the study, head and neck injuries were examined by placing test dummies to examine human injury behavior in modular buildings exposed to blast loads. Obtained results were compared with field tests. In both cases, results close to field tests were obtained. Thus, it was concluded that Stribeck curves and Pais Kausel equations can reflect the behavior of modular buildings subjected to blast loads. It was also seen at the end of the study that the human injury criteria were met. The results of the study are explained with their justifications.
Key Words
blast loads; BRBM; human injury response; modular structures
Address
Ali Sari, Kadir Guler, Sayed Mahdi Hashemi: Faculty of Civil Engineering, Istanbul Technical University, Maslak, Istanbul, Türkiye
Omer Faruk Nemutlu: Civil Engineering Department, Bingol University, Bingöl, Türkiye
Abstract
This study examines crack behavior within orthopedic cement utilized in total hip replacements through the finite
element method. Its main goal is to compute stress intensity factors (SIF) near the crack tip. The analysis encompasses two load types, static and dynamic, applied to a crack starting from the interface between the cement and bone. Specifically, it investigates SIFs under mixed mode conditions during three activities: normal walking, climbing upstairs, and downstairs. The results highlight that a crack originating from a micro-interface under substantial loading can cause cement damage, leading to prosthetic loosening. Stress intensity factors in modes I, II, and III are influenced by the crack tip's orientation and location in the bone cement, with a 90o orientation yielding notably higher values across all three modes.
Key Words
cement; elliptical crack; implant; stress intensity factors
Address
Ali Benouis: Dr. Moulay Tahar, University of Saida, Bp 138 Saida, 20000, Algeria; LMPM, Djillali Liabes University of Sidi Bel-Abbes, Algeria
Mohammed El Sallah Zagane: LMPM, Djillali Liabes University of Sidi Bel-Abbes, Algeria
Abdelmadjid Moulgada: LMPM, Djillali Liabes University of Sidi Bel-Abbes, Algeria; Ibn Khladoun, University of Tiaret, 14000, Algeria
Murat Yaylaci: Biomedical Engineering MSc Program, Recep Tayyip Erdogan University, 53100, Rize, Turkey; Department of Civil Engineering, Recep Tayyip Erdogan University, 53100, Rize, Turkey; Turgut K
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