Abstract Layered composite materials are widely used across a variety of sectors, including the automotive industry, aerospace engineering, offshore, and various mechanical domains, because of their strong yet lightweight structures. Therefore, various emergent theories are available on the deformation of layered beams. The previous research studies are insufficient as they are based on deformation of layered composite and sandwich arches with simply supported (SS) end conditions. Therefore, it is a good opportunity for researchers to investigate the arches using exponential shear deformation and normal deformation theory. The leading hypothesis mainly adds to the research of bending for sandwich and layered composite arches adopting the exponential theory. The present theory does not require any shear correction factor to satisfy zero transverse shear stress condition at the bottom and top fibers of arches. Governing equations and associated end conditions are derived through principle of virtual work. Navier’s techniques used for sandwich and layered composite arches are SS boundary conditions subjected to uniformly distributed load. The results of the current study showed that the exponential normal and shear deformation theories may be used to evaluate static responses for layered composite and sandwich arches. The obtained results from the present theory are validated through the results available in published literature.
{"title":"Evaluation of static responses for layered composite arches","authors":"V. M. Mahajan, Amit Sharma","doi":"10.1515/cls-2022-0185","DOIUrl":"https://doi.org/10.1515/cls-2022-0185","url":null,"abstract":"Abstract Layered composite materials are widely used across a variety of sectors, including the automotive industry, aerospace engineering, offshore, and various mechanical domains, because of their strong yet lightweight structures. Therefore, various emergent theories are available on the deformation of layered beams. The previous research studies are insufficient as they are based on deformation of layered composite and sandwich arches with simply supported (SS) end conditions. Therefore, it is a good opportunity for researchers to investigate the arches using exponential shear deformation and normal deformation theory. The leading hypothesis mainly adds to the research of bending for sandwich and layered composite arches adopting the exponential theory. The present theory does not require any shear correction factor to satisfy zero transverse shear stress condition at the bottom and top fibers of arches. Governing equations and associated end conditions are derived through principle of virtual work. Navier’s techniques used for sandwich and layered composite arches are SS boundary conditions subjected to uniformly distributed load. The results of the current study showed that the exponential normal and shear deformation theories may be used to evaluate static responses for layered composite and sandwich arches. The obtained results from the present theory are validated through the results available in published literature.","PeriodicalId":44435,"journal":{"name":"Curved and Layered Structures","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46577328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This article provides a new finite-element procedure based on Reddy’s third-order shear deformation plate theory (TSDT) to establish the motion equation of functionally graded porous (FGP) sandwich plates resting on Kerr foundation (KF). Although Reddy’s TSDT is attractive, it cannot be exploited as expected in finite-element analysis due to the difficulties in satisfying the zero shear stress boundary condition. In this study, the proposed element has four nodes, each with seven degrees of freedom (DOF). The performance of this element is confirmed by conducting various examples, showing its accuracy and range of applications. Then, some studies are performed to present the effects of input parameters on the vibration of FGP sandwich plates resting on KF.
{"title":"A new finite-element procedure for vibration analysis of FGP sandwich plates resting on Kerr foundation","authors":"Ngoc-Tu Do, T. T. Tran, Q. Pham","doi":"10.1515/cls-2022-0195","DOIUrl":"https://doi.org/10.1515/cls-2022-0195","url":null,"abstract":"Abstract This article provides a new finite-element procedure based on Reddy’s third-order shear deformation plate theory (TSDT) to establish the motion equation of functionally graded porous (FGP) sandwich plates resting on Kerr foundation (KF). Although Reddy’s TSDT is attractive, it cannot be exploited as expected in finite-element analysis due to the difficulties in satisfying the zero shear stress boundary condition. In this study, the proposed element has four nodes, each with seven degrees of freedom (DOF). The performance of this element is confirmed by conducting various examples, showing its accuracy and range of applications. Then, some studies are performed to present the effects of input parameters on the vibration of FGP sandwich plates resting on KF.","PeriodicalId":44435,"journal":{"name":"Curved and Layered Structures","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45584515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Aribowo, M. I. Adhynugraha, Fadli Cahya Megawanto, Arif Hidayat, T. Muttaqie, F. A. Wandono, Abian Nurrohmad, Chairunnisa, Sherly Octavia Saraswati, Ilham Bagus Wiranto, Iqbal Reza Al Fikri, M. Saputra
Abstract This research applies a numerical study of topology optimization of laminate composite structures by using a finite element method (FEM). In this methodology, the plies orientation is excluded from the optimization. The geometry-based optimization from frames of a MALE UAV fuselage structure is presented. The minimum strain energy with an optimization constraint of 20% of weight reduction is used in the objective function. Before the primary analysis, benchmark studies of topology optimization without considering orientations from previously published literature are performed. The convergence studies were taken to acquire the appropriate mesh size in the FEM technique, which utilized a four-noded shell element. The finite element analysis and optimization results showed that the structural design of the newly framed composite fuselage MALE UAV meets the structural strength requirements specified in the airworthiness standard STANAG 4671.
{"title":"Finite element method on topology optimization applied to laminate composite of fuselage structure","authors":"A. Aribowo, M. I. Adhynugraha, Fadli Cahya Megawanto, Arif Hidayat, T. Muttaqie, F. A. Wandono, Abian Nurrohmad, Chairunnisa, Sherly Octavia Saraswati, Ilham Bagus Wiranto, Iqbal Reza Al Fikri, M. Saputra","doi":"10.1515/cls-2022-0191","DOIUrl":"https://doi.org/10.1515/cls-2022-0191","url":null,"abstract":"Abstract This research applies a numerical study of topology optimization of laminate composite structures by using a finite element method (FEM). In this methodology, the plies orientation is excluded from the optimization. The geometry-based optimization from frames of a MALE UAV fuselage structure is presented. The minimum strain energy with an optimization constraint of 20% of weight reduction is used in the objective function. Before the primary analysis, benchmark studies of topology optimization without considering orientations from previously published literature are performed. The convergence studies were taken to acquire the appropriate mesh size in the FEM technique, which utilized a four-noded shell element. The finite element analysis and optimization results showed that the structural design of the newly framed composite fuselage MALE UAV meets the structural strength requirements specified in the airworthiness standard STANAG 4671.","PeriodicalId":44435,"journal":{"name":"Curved and Layered Structures","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47587853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Tuswan, P. Manik, Samuel Samuel, A. Suprihanto, S. Sulardjaka, Sri Nugroho, Boris Ferdinando Pakpahan
Abstract With the increased emphasis on the use of recyclable bio-based materials and further understanding of the mechanical properties of laminated bamboo, the development of a new generation of low-cost bamboo-based composites for ship structure has generated a significant interest. Laminated bamboo composites comprising Apus bamboo (Gigantochloa apus) and Waru fiber at different layer orientations were investigated to obtain the mechanical characteristics. The influence of different laminate directions was studied through several methods of mechanical testing, including impact tests using ASTM D256, bending tests using ASTM D7264, and tensile tests using ASTM D3039. Results showed that material strength properties could be improved by using on-axis direction (0°). The bamboo composites with unidirectional (0°) laminate direction exhibited superior mechanical properties to bidirectional laminate directions (45°/−45° and 0°/90°). The addition of Waru fiber improved the mechanical properties of the currently developed material; that is, bending strength increased by about 3.17–14.18% and tensile strength was in the range of 4.88–20.28%. Only those composites with 0° and 0°/90° layer orientations fulfilled the Indonesian Bureau Classification strength threshold.
{"title":"Correlation between lamina directions and the mechanical characteristics of laminated bamboo composite for ship structure","authors":"T. Tuswan, P. Manik, Samuel Samuel, A. Suprihanto, S. Sulardjaka, Sri Nugroho, Boris Ferdinando Pakpahan","doi":"10.1515/cls-2022-0186","DOIUrl":"https://doi.org/10.1515/cls-2022-0186","url":null,"abstract":"Abstract With the increased emphasis on the use of recyclable bio-based materials and further understanding of the mechanical properties of laminated bamboo, the development of a new generation of low-cost bamboo-based composites for ship structure has generated a significant interest. Laminated bamboo composites comprising Apus bamboo (Gigantochloa apus) and Waru fiber at different layer orientations were investigated to obtain the mechanical characteristics. The influence of different laminate directions was studied through several methods of mechanical testing, including impact tests using ASTM D256, bending tests using ASTM D7264, and tensile tests using ASTM D3039. Results showed that material strength properties could be improved by using on-axis direction (0°). The bamboo composites with unidirectional (0°) laminate direction exhibited superior mechanical properties to bidirectional laminate directions (45°/−45° and 0°/90°). The addition of Waru fiber improved the mechanical properties of the currently developed material; that is, bending strength increased by about 3.17–14.18% and tensile strength was in the range of 4.88–20.28%. Only those composites with 0° and 0°/90° layer orientations fulfilled the Indonesian Bureau Classification strength threshold.","PeriodicalId":44435,"journal":{"name":"Curved and Layered Structures","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48829177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Adiputra, Faiz Nur Fauzi, Nurman Firdaus, Eko Marta Suyanto, Afian Kasharjanto, Navik Puryantini, Erwandi Erwandi, Rasgianti Rasgianti, Aditya Rio Prabowo
Abstract Spar-type floating offshore wind turbine has been massively developed considering its design simplicity and stability to withstand the wave-induced motion. However, the variation of the local sea level and the readiness of supporting production facilities demand the spar design to adapt in a viable way. Considering this, the present article investigated how the slenderness (length over diameter ratio) and the roundness of cross section influence the hydrodynamic characteristics, which are the crucial parameters of floater performances. The OC3-Hywind spar-type floating platform was adapted as the reference model. The length of the reference floater was then varied with a ratio of 1.5, 2, 2.5, and 3 and the diameter was proportionally scaled to obtain constant buoyancy. The number of the sides which indicated the roundness of the cross section was varied to be 4, 6, 8, 10, 12, 14, and infinity (cylindrical shape). The analysis was conducted using potential flow theory in a boundary element method solver through an open-source code NEMOH. Initially, panel convergence was conducted and compared with the experimental results of the reference model to obtain the appropriate simulation settings before being used for the case configuration analysis. Results stated that the roundness effect with sides greater than 16 had little effect on dynamic characteristics. Meanwhile, the spar with the largest diameter was more stable against the translational motion.
{"title":"Roundness and slenderness effects on the dynamic characteristics of spar-type floating offshore wind turbine","authors":"R. Adiputra, Faiz Nur Fauzi, Nurman Firdaus, Eko Marta Suyanto, Afian Kasharjanto, Navik Puryantini, Erwandi Erwandi, Rasgianti Rasgianti, Aditya Rio Prabowo","doi":"10.1515/cls-2022-0213","DOIUrl":"https://doi.org/10.1515/cls-2022-0213","url":null,"abstract":"Abstract Spar-type floating offshore wind turbine has been massively developed considering its design simplicity and stability to withstand the wave-induced motion. However, the variation of the local sea level and the readiness of supporting production facilities demand the spar design to adapt in a viable way. Considering this, the present article investigated how the slenderness (length over diameter ratio) and the roundness of cross section influence the hydrodynamic characteristics, which are the crucial parameters of floater performances. The OC3-Hywind spar-type floating platform was adapted as the reference model. The length of the reference floater was then varied with a ratio of 1.5, 2, 2.5, and 3 and the diameter was proportionally scaled to obtain constant buoyancy. The number of the sides which indicated the roundness of the cross section was varied to be 4, 6, 8, 10, 12, 14, and infinity (cylindrical shape). The analysis was conducted using potential flow theory in a boundary element method solver through an open-source code NEMOH. Initially, panel convergence was conducted and compared with the experimental results of the reference model to obtain the appropriate simulation settings before being used for the case configuration analysis. Results stated that the roundness effect with sides greater than 16 had little effect on dynamic characteristics. Meanwhile, the spar with the largest diameter was more stable against the translational motion.","PeriodicalId":44435,"journal":{"name":"Curved and Layered Structures","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44486167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract During an evacuation, the tsunami lifeboat should be able to withstand the possible external loads that might be occurred, such as collisions, violent crashes, and capsizing events. Special structural reinforcement and improvement, such as a crash absorber, are attached to prevent damage due to the impact load. Therefore, this article focuses on the crushing behaviour of the tsunami lifeboat crash absorber made of the multi-cell glass fibre-reinforced composite panel. The effect of the cross-section geometry design of the cell on the damage mechanism and energy absorption behaviour was investigated. The explicit dynamic finite element method was used to identify the multi-cell configuration’s crashworthiness performance. Experimental studies such as tensile and three-point bending tests were conducted to define the material properties and validation of the FE model. The simulation results showed that the explicit dynamic finite element method has effectively estimated the crash absorber crushing damage. The circular cross-section has shown the most significant crash absorption capability compared to the others, namely the honeycomb, the square, and the triangular cell. Furthermore, the 4CSM laminate type has revealed a lower energy absorption than the 4WRC45 and 4WRC laminates. Otherwise, the study exhibits that the cross-sectional geometry and the laminate type significantly influence the crash absorber performance for improving the tsunami lifeboat crashworthiness.
{"title":"Numerical study on crushing damage and energy absorption of multi-cell glass fibre-reinforced composite panel: Application to the crash absorber design of tsunami lifeboat","authors":"Ahmad Fauzan Zakki, Aulia Windyandari","doi":"10.1515/cls-2022-0211","DOIUrl":"https://doi.org/10.1515/cls-2022-0211","url":null,"abstract":"Abstract During an evacuation, the tsunami lifeboat should be able to withstand the possible external loads that might be occurred, such as collisions, violent crashes, and capsizing events. Special structural reinforcement and improvement, such as a crash absorber, are attached to prevent damage due to the impact load. Therefore, this article focuses on the crushing behaviour of the tsunami lifeboat crash absorber made of the multi-cell glass fibre-reinforced composite panel. The effect of the cross-section geometry design of the cell on the damage mechanism and energy absorption behaviour was investigated. The explicit dynamic finite element method was used to identify the multi-cell configuration’s crashworthiness performance. Experimental studies such as tensile and three-point bending tests were conducted to define the material properties and validation of the FE model. The simulation results showed that the explicit dynamic finite element method has effectively estimated the crash absorber crushing damage. The circular cross-section has shown the most significant crash absorption capability compared to the others, namely the honeycomb, the square, and the triangular cell. Furthermore, the 4CSM laminate type has revealed a lower energy absorption than the 4WRC45 and 4WRC laminates. Otherwise, the study exhibits that the cross-sectional geometry and the laminate type significantly influence the crash absorber performance for improving the tsunami lifeboat crashworthiness.","PeriodicalId":44435,"journal":{"name":"Curved and Layered Structures","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135401333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The properties of epoxy asphalt materials and carbon fiber composites are closely related to temperature, so it is important to study the mechanical properties of these two materials when they are used in track at different temperatures. The parallel analysis method is adopted in this study. The carbon fiber composite is regarded as a continuous elastomer, and its stress and strain components are fully expressed in a matrix form in a three-dimensional coordinate system. Finally, 21 elastic constants are selected. At the same time, the mechanical properties of epoxy asphalt materials in viscoelastic and tensile aspects were studied considering the temperature zone expansion factor. The results show that the maximum degradation of carbon fiber composites in tensile strength occurs at low temperature and dry state, and the degradation rate is 30.8%. In terms of compressive strength, the maximum degradation rate of the material is 21.9% under high temperature and wet conditions. The elongation at break of epoxy asphalt materials showed a trend of first increasing and then decreasing. In the whole working temperature zone, it increased from 311.78 to 354.55% and then decreased to 228.89%. The bond elongation first increases and then decreases. Taking 0℃ as the dividing point, the bond elongation increases from 85.7% at − 20℃ to 256.7% at 0℃ in the temperature zone below 0℃, while it decreases from 256.7% at 0℃ to 80.6% in the temperature zone above 0℃. Therefore, the mechanical properties of the two materials have the characteristics of high temperature sensitivity.
{"title":"Influence of the selection of different construction materials on the stress–strain state of the track","authors":"ZhiWei Yin","doi":"10.1515/cls-2022-0203","DOIUrl":"https://doi.org/10.1515/cls-2022-0203","url":null,"abstract":"Abstract The properties of epoxy asphalt materials and carbon fiber composites are closely related to temperature, so it is important to study the mechanical properties of these two materials when they are used in track at different temperatures. The parallel analysis method is adopted in this study. The carbon fiber composite is regarded as a continuous elastomer, and its stress and strain components are fully expressed in a matrix form in a three-dimensional coordinate system. Finally, 21 elastic constants are selected. At the same time, the mechanical properties of epoxy asphalt materials in viscoelastic and tensile aspects were studied considering the temperature zone expansion factor. The results show that the maximum degradation of carbon fiber composites in tensile strength occurs at low temperature and dry state, and the degradation rate is 30.8%. In terms of compressive strength, the maximum degradation rate of the material is 21.9% under high temperature and wet conditions. The elongation at break of epoxy asphalt materials showed a trend of first increasing and then decreasing. In the whole working temperature zone, it increased from 311.78 to 354.55% and then decreased to 228.89%. The bond elongation first increases and then decreases. Taking 0℃ as the dividing point, the bond elongation increases from 85.7% at − 20℃ to 256.7% at 0℃ in the temperature zone below 0℃, while it decreases from 256.7% at 0℃ to 80.6% in the temperature zone above 0℃. Therefore, the mechanical properties of the two materials have the characteristics of high temperature sensitivity.","PeriodicalId":44435,"journal":{"name":"Curved and Layered Structures","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135748723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The research starts with the treatment of the multiscale transmission problem and establishes the electromagnetic solidification transmission coupling mathematical model based on the indirect coupling method. It uses the three-dimensional magnetic field finite element theory to establish a three-dimensional crucible structure continuous casting model built on the electromagnetic solidification transmission coupling mathematical model. This model is used to optimize the parameters of the composite crucible structure and to simulate electromagnetic transmission and braking phenomena. The results show that the L-shaped static magnetic field has a more potent inhibition and a guidance effect on melt circulation. The braking effect of the actual magnetic field on the downward impact is worse. Under the influence of an L-shaped magnetic field, the flow velocity of the melt is better, and the flow state distribution is more smooth and uniform. The computational efficiency test results show that the conversion calculation time of the method designed in this study is 18.03 min. The total calculation time is 680.48 min, which is superior to traditional methods. It proves that this model can accurately analyze the magnetic field coupling problem and at the same time ensure the superiority of its computing efficiency.
{"title":"Optimization of structural parameters and numerical simulation of stress field of composite crucible based on the indirect coupling method","authors":"Chunlei Jiang","doi":"10.1515/cls-2022-0198","DOIUrl":"https://doi.org/10.1515/cls-2022-0198","url":null,"abstract":"Abstract The research starts with the treatment of the multiscale transmission problem and establishes the electromagnetic solidification transmission coupling mathematical model based on the indirect coupling method. It uses the three-dimensional magnetic field finite element theory to establish a three-dimensional crucible structure continuous casting model built on the electromagnetic solidification transmission coupling mathematical model. This model is used to optimize the parameters of the composite crucible structure and to simulate electromagnetic transmission and braking phenomena. The results show that the L-shaped static magnetic field has a more potent inhibition and a guidance effect on melt circulation. The braking effect of the actual magnetic field on the downward impact is worse. Under the influence of an L-shaped magnetic field, the flow velocity of the melt is better, and the flow state distribution is more smooth and uniform. The computational efficiency test results show that the conversion calculation time of the method designed in this study is 18.03 min. The total calculation time is 680.48 min, which is superior to traditional methods. It proves that this model can accurately analyze the magnetic field coupling problem and at the same time ensure the superiority of its computing efficiency.","PeriodicalId":44435,"journal":{"name":"Curved and Layered Structures","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43459489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The rising demand for liquefied natural gas (LNG)-fueled ships requires the LNG bunkering facility that partially uses a ship-to-ship operation. The bunkering process of LNG fuel may have a greater risk due to LNG volatility. The cryogenic temperature of LNG poses a threat to the personnel and structural embrittlement to ships. Therefore, cryogenic spill protection optimization was introduced concerning the structural strength analysis using finite element (FE) by utilizing cryogenic temperature loads provided by the computational fluid dynamics (CFD) model of an LNG release. This study aims to build a platform for transferring the temperature load profile from CFD to FE software accurately. The CFD model usually uses a structured Cartesian grid, and the FE method adopts an unstructured tetrahedral or hexahedral mesh. As a result, both configurations store results at different positions, and it is not preferred for the load profile to be transferred directly. The error will be greater due to the variance of positions. Random Forest, a machine learning method, has been employed that uses a regression technique to deal with a continuous variable. An accurate load profile for the FE model can be obtained by adopting decision tree learning in Random Forest. The procedure for determining the temperature load profile is presented in this article.
{"title":"Determination of cryogenic temperature loads for finite-element model of LNG bunkering ship under LNG release accident","authors":"H. Nubli, J. Sohn, Sangjin Kim","doi":"10.1515/cls-2022-0205","DOIUrl":"https://doi.org/10.1515/cls-2022-0205","url":null,"abstract":"Abstract The rising demand for liquefied natural gas (LNG)-fueled ships requires the LNG bunkering facility that partially uses a ship-to-ship operation. The bunkering process of LNG fuel may have a greater risk due to LNG volatility. The cryogenic temperature of LNG poses a threat to the personnel and structural embrittlement to ships. Therefore, cryogenic spill protection optimization was introduced concerning the structural strength analysis using finite element (FE) by utilizing cryogenic temperature loads provided by the computational fluid dynamics (CFD) model of an LNG release. This study aims to build a platform for transferring the temperature load profile from CFD to FE software accurately. The CFD model usually uses a structured Cartesian grid, and the FE method adopts an unstructured tetrahedral or hexahedral mesh. As a result, both configurations store results at different positions, and it is not preferred for the load profile to be transferred directly. The error will be greater due to the variance of positions. Random Forest, a machine learning method, has been employed that uses a regression technique to deal with a continuous variable. An accurate load profile for the FE model can be obtained by adopting decision tree learning in Random Forest. The procedure for determining the temperature load profile is presented in this article.","PeriodicalId":44435,"journal":{"name":"Curved and Layered Structures","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43396339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Recently, the use of reinforced concrete (RC) structures is becoming very common worldwide. Because of earthquakes or poor design, some of these structures need to be retrofitted. Among different methods of retrofitting a structure, we have utilized a steel cage to support a column under axial load. The numerical modeling of a retrofitted column with a steel cage is carried out by the finite-element method in ABAQUS, and the effectiveness of the number of strips, size of strips, size of angles, RC head, the strips’ thickness, and the steel cage’s mechanical properties are studied on 15 different case studies by the single factorial method. These parameters proved to be very effective on the load distribution of the column because by choosing the optimum case, lower amounts of force are born by the column. By increasing the number of strips, the steel cage would reach 52% of the total load. This value for the size of strips and angles’ size is 48 and 50%, respectively. However, the thickness of the strips does not have a significant effect on the load bearing of the column. In order to fully predict the load distribution of the retrofitted columns, the data of the present study are utilized to propose a predictive model for N c/P FEM and N c/P FEM using artificial neural networks. The model had an error of 1.56 (MAE), and the coefficient of determination was 0.97. This model proved to be so accurate that it could replace time-consuming numerical modeling and tedious experiments.
{"title":"Parametric study of retrofitted reinforced concrete columns with steel cages and predicting load distribution and compressive stress in columns using machine learning algorithms","authors":"Larah R. Abdulwahed","doi":"10.1515/cls-2022-0197","DOIUrl":"https://doi.org/10.1515/cls-2022-0197","url":null,"abstract":"Abstract Recently, the use of reinforced concrete (RC) structures is becoming very common worldwide. Because of earthquakes or poor design, some of these structures need to be retrofitted. Among different methods of retrofitting a structure, we have utilized a steel cage to support a column under axial load. The numerical modeling of a retrofitted column with a steel cage is carried out by the finite-element method in ABAQUS, and the effectiveness of the number of strips, size of strips, size of angles, RC head, the strips’ thickness, and the steel cage’s mechanical properties are studied on 15 different case studies by the single factorial method. These parameters proved to be very effective on the load distribution of the column because by choosing the optimum case, lower amounts of force are born by the column. By increasing the number of strips, the steel cage would reach 52% of the total load. This value for the size of strips and angles’ size is 48 and 50%, respectively. However, the thickness of the strips does not have a significant effect on the load bearing of the column. In order to fully predict the load distribution of the retrofitted columns, the data of the present study are utilized to propose a predictive model for N c/P FEM and N c/P FEM using artificial neural networks. The model had an error of 1.56 (MAE), and the coefficient of determination was 0.97. This model proved to be so accurate that it could replace time-consuming numerical modeling and tedious experiments.","PeriodicalId":44435,"journal":{"name":"Curved and Layered Structures","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43792684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：