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Challenge Journal of Structural Mechanics
Number of Followers: 7  Open Access journalISSN (Online) 2149-8024 Published by TULPAR Academic Publishing  [2 journals]
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- Cover & Contents Vol.10 No.2
Authors: Journal Management CJSMEC
PubDate: 2024-06-13
Issue No: Vol. 10, No. 2 (2024)
- Ultimate drift ratio prediction of steel plate shear wall systems: a
machine learning approach
Authors: Muhammed Gürbüz, İlker Kazaz
Pages: 34 - 46
Abstract: Predicting the ultimate drift ratio of steel plate shear wall (SPSW) systems is important for ensuring the structural integrity and performance of these systems under lateral loads. In this study, machine learning models are developed for predicting the ultimate drift ratio based on various design parameters using data from previous research on SPSW systems. These design parameters include the panel aspect ratio, column flexibility parameter, axial load ratio, web plate thickness and stiffness of horizontal and vertical boundary elements. A range of machine learning models is considered, including Random Forest, Lasso, Gradient Boosting, XGBoost, Adaboost, Artificial Neural Network and a stacked regressor. The models are trained and evaluated using data from 292 different SPSW models, and their performance is compared based on the R-squared value, root mean squared error (RMSE), and evaluation time. The results of this study demonstrate the effectiveness of machine learning techniques for predicting the ultimate drift ratio of SPSW systems. The results of this study show that machine learning techniques effectively predict the ultimate drift ratio of SPSW systems. Among the models considered, the ANN model achieved the highest R2 value, with a value of 0.94.
PubDate: 2024-06-13
DOI: 10.20528/cjsmec.2024.02.001
Issue No: Vol. 10, No. 2 (2024)
- The novelty design method in lightweight structures with low effective
elastic modulus
Authors: Hojjat Ghahramanzadeh Asl, Derya Karaman
Pages: 47 - 57
Abstract: Lightweight structures are of great interest in industrial areas such as automotive, aerospace, and biomedical due to their lightness, and superior mechanical performance. The advantages of lightweight structures are increased with the spread of additive manufacturing and design them in various geometries. Beam-based structures and triply periodic minimal surface structures are currently used to extend these advantages. In this study, it is aimed to create die models of beam-based structures in order to contribute to the geometric diversity for lightweight structures. By designing the die lattice structures of the beam-based structures, the comparison of the mechanical performance of basic lattice and die lattice structures with the same porosity was carried out. For FCC, CFCC, and Octet-Truss lattice structures, basic lattice and die lattice structures are designed on scaffolds in 5x5x5 array with 50%, 60%, 70%, and 80% porosity. Numerical data were obtained for Ti6Al4V with compression tests simulated by applying pressure in the -y direction. According to numerical analyses, the effective elastic modulus decreased due to the increased porosity in both structure models. The CFCC and Octet Truss scaffolds have different force transmission performances. Likewise, this situation is observed in die lattice structures, but the force transmission with the surfaces reveals the difference of the structures. The effective elastic modulus of basic lattice structure with 80% porosity of the Octet Truss structure is approximately twice that of the die lattice structure. Thus, the use of die lattice structures will provide advantages for the design of lightweight structures with low elastic modulus.
PubDate: 2024-06-13
DOI: 10.20528/cjsmec.2024.02.002
Issue No: Vol. 10, No. 2 (2024)
- Effect of different trimline extension of clear aligners in combination
with Class II elastics on the mandibular dentition: a finite element
analysis
Authors: Nurver Karslı, Bahanur Hilal Kisbet
Pages: 58 - 68
Abstract: Objective of this study is to evaluate the effect of different trimline extension of aligners and the effect of elastics applied through the slit cutouts and buttons on the mandibular dentition using Class II intermaxillary elastics combined with clear aligner treatment. Three-dimensional (3D) finite element models that simulate the effects of Class II elastics on the mandibular arch in four different scenarios were studied, named, straight and high trimline aligner (HTLA) model with elastic applied through buttons (Model 1), straight and low trimline aligner (LTLA) model with elastic applied through buttons (Model 2), HTLA model with elastic applied through slit cutout (Model 3), LTLA model with elastic applied through slit cutout (Model 4). 3D displacements of the teeth, von Mises stress (VMS) in the periodontal ligament (PDL) were calculated. In all models, the crown of the mandibular anterior teeth moved labially, the root moved lingually, and the mandibular first molars moved mesially. Among all models, labialization of incisors and mesialization of molars was highest in Model 2 and lowest in Model 3. In clear aligner treatment combined with Class II elastics, HTLA was more effective in controlling mandibular incisor proclination and mesial tipping of mandibular molars. The slit cutout models were more effective in controlling mesial tipping of mandibular molars.
PubDate: 2024-06-13
DOI: 10.20528/cjsmec.2024.02.003
Issue No: Vol. 10, No. 2 (2024)
- From ruins to reconstruction: Harnessing text-to-image AI for restoring
historical architectures
Authors: Kawsar Arzomand, Michael Rustell, Tatiana Kalganova
Pages: 69 - 85
Abstract: The preservation of cultural heritage has become increasingly important in the face of conflicts and natural disasters that threaten historical sites worldwide. This study explores the application of artificial intelligence (AI), specifically text-to-image generation technologies, in reconstructing heritage sites damaged by these adversities. Utilising detailed textual descriptions and historical records, this study employed AI to produce accurate visual representations of damaged heritage sites, bridging the gap between traditional documentation and modern digital reconstruction methods. This approach not only enhances the architectural design process across various disciplines but also initiates a paradigm shift towards more dynamic, intuitive, and efficient heritage conservation practices. The methodology integrates data collection, iterative AI-generated image production, expert review, and comparative analysis against historical data to evaluate reconstruction accuracy and authenticity. By integrating AI with traditional preservation practices, this study advocates a balanced approach to conserving cultural legacies, ensuring their preservation and revitalisation for future generations. Preliminary findings suggest that AI-generated imagery holds significant promise for enhancing digital heritage preservation by offering novel approaches for visualising and understanding historical sites. These findings also highlight the need to address ethical, technical, and collaborative challenges to enhance the precision, reliability, and applicability of AI technologies in the field of cultural heritage. This study contributes to digital humanities and archaeological conservation, demonstrating AI's potential to support and complement traditional heritage preservation methods and suggests a pathway for substantial methodological evolution in the field.
PubDate: 2024-06-13
DOI: 10.20528/cjsmec.2024.02.004
Issue No: Vol. 10, No. 2 (2024)
- Cover & Contents Vol.10 No.1
Authors: Journal Management CJSMEC
PubDate: 2024-03-09
Issue No: Vol. 10, No. 1 (2024)
- Strengthening of historic masonry vaults with CFRP prepreg
Authors: İsmail Hakkı Tarhan, Habib Uysal
Pages: 1 - 6
Abstract: Masonry vaults, frequently used in historic buildings to create large openings, have played a critical role in the survival of these buildings to the present day. These structural elements, which have been exposed to destructive effects such as earthquakes for centuries, need strengthening activities in order to transfer cultural heritage to future generations. The use of composite materials with high mechanical properties for strengthening purposes has been a popular method since the beginning of the 21st century, and its effectiveness has been proven. In this study, a masonry vault in the historical redoubts located in Erzurum, Türkiye, was modelled, and the effectiveness of various strengthening scenarios using prepreg composites was investigated. Numerical simulations were conducted with the Finite element method-based macro modelling approach. The investigation revealed that retrofitting arrangements maintained the stress distribution in masonry vaults while reducing maximum tensile stress; intrados reinforcement proved more effective, particularly the intrados-straight retrofit, with a 24% improvement, whereas extrados strengthening showed limited effectiveness.
PubDate: 2024-03-09
DOI: 10.20528/cjsmec.2024.01.001
Issue No: Vol. 10, No. 1 (2024)
- Effect of soil types on nonlinear earthquake behavior of buildings
Authors: Memduh Karalar, Murat Demirköse, Necati Mert
Pages: 7 - 13
Abstract: The Winkler method, which is widely used today, assumes that the soil behaves elastically and does not take into account the soil shear stress values, it is insufficient to reflect the actual soil behavior. Especially in the earthquake calculations of rigid and massive structures such as high-rise buildings, dams, suspension bridges, viaducts, it is necessary to consider soil as a dynamic system that changes shape and affects the behavior of the structure in terms of inertia. In response to the effect of soil on the structure, the structure also affects soil both kinematically and dynamically. Thus, in the absence of the structure, the earthquake data, which is only a result of the dynamic behavior of the soil in its internal structure, now acquires a more complex soil motion characteristic that is also affected by the presence of the structure. The observations made in some earthquakes show that the changes between the records taken simultaneously on the building foundation and at soil surface not a point far from foundation, show that the structure also affects soil therefore soil motion in response to the effect of the earthquake on the structure. In this study, the effect of soil types on the nonlinear seismic behavior of reinforced concrete structures was investigated. For this purpose, 7-storey building models with different plans and rigidities were created. The behavior of these models under 11 different earthquake loads for the ZA, ZB, ZC, ZD, ZE soil types specified in the Turkish Building Earthquake Code has been investigated. Analyzes were made using the time history method with the help of the SAP2000 program. As a result of the analysis, the displacements, plastic hinge formation, Effective inter-storey drift and period values obtained for different models were compared.
PubDate: 2024-03-09
DOI: 10.20528/cjsmec.2024.01.002
Issue No: Vol. 10, No. 1 (2024)
- Size effect on compressive behavior of GFRP bars
Authors: Meltem Eryılmaz Yıldırım, Kerem Aybar, Mehmet Canbaz
Pages: 14 - 20
Abstract: In the last three decades, studies investigating the use of Glass Fiber Reinforced Polymer (GFRP) bars as an alternative to conventional steel rebars have increased due to their corrosive resistance. In addition to corrosion resistance, GFRP bars utilize high specific tensile strength, which makes them highly desirable in civil engineering applications. However, major design guidelines for GFRP-reinforced concrete structures currently do not consider their compressive contribution. Nevertheless, there is a growing trend in utilizing GFRP bars as compressive elements, driven by various studies demonstrating their ability to bear compressive loads effectively. This increasing demand underscores the need to comprehend the mechanical properties of GFRP bars, particularly in terms of their compressive behavior. Furthermore, a standardized test method to evaluate their compressive properties has not yet been developed. Addressing these gaps, this research paper focuses on investigating the influence of specimen size on the compressive strength of GFRP bars, specifically emphasizing on the compressive properties of GFRP bars. Compressive tests were conducted on GFRP specimens with varying diameters while maintaining a constant slenderness ratio. The findings from these compression tests shed light on the critical role of size in the compressive behavior of GFRP. This research emphasizes the importance of considering size as a significant parameter in designing mechanical properties for GFRP reinforcements.
PubDate: 2024-03-09
DOI: 10.20528/cjsmec.2024.01.003
Issue No: Vol. 10, No. 1 (2024)
- Structural behavior of historical Obruk Inn under different earthquakes
Authors: Süleyman Kamil Akın, Ahmet Alagöz
Pages: 21 - 33
Abstract: Masonry structures is one of the most preferred structure types throughout history. The advantageous of these structures can be categorized as longevity, affordability and easy access to materials. Due to a lack of information and constructive errors, masonry structures suffer major damage under effect of earthquakes. While the vertical load carrying capacity of a masonry structure is excellent, its performance under horizontal loads is very poor. The brittle behavior of masonry structures, in particular, causes the structure to suffer significant damage or collapse completely during an earthquake. Türkiye is situated over a major earthquake zone. Throughout history, there has been numerous major earthquakes. These earthquakes have demolished the masonry structures resulted in significant life and economic losses. Therefore, in recent days, the examination of the seismic resilience performance of masonry structures as well as the required strengthening have become a pivotal issue. Thus, the aim of this study is to analyze the seismic performance of historical Obruk Inn subjected to different earthquake effects via finite elements method (FEM). To do this, the plans obtained from on-site inspections for historical Obruk Inn to create structural FEM model and its performance was evaluated under the influence of various earthquake excitations. As a result of the analyses, it was determined that the historical Obruk Inn structure should have immediate be strengthened against a possible earthquake.
PubDate: 2024-03-09
DOI: 10.20528/cjsmec.2024.01.004
Issue No: Vol. 10, No. 1 (2024)
