Pub Date : 2024-12-16DOI: 10.1016/j.engstruct.2024.119451
J.J. Wang , X.F. Nie , L. Yang , W.G. Li , S.S. Zhang
Hybrid fiber-reinforced polymer (FRP)-concrete-steel double-skin tubular columns (DSTCs) have been proved an effective structural form to achieve both high strength and ductility. While existing studies on such columns were mainly focused on the use of normal-strength/high-strength concrete as infilling materials, the use of ultra-high-performance concrete (UHPC) to improve the behavior of such columns is attracting increasing attention. For the same demand on load-carrying capacity, the use of UHPC in DSTCs can largely reduce the cross-sectional area and thus the weight of DSTCs, improving the seismic performance of DSTCs. On the other hand, the use of UHPC in DSTSs is able to achieve a much higher load-carrying capacity if the size of the compressive member is limited. To date, limited research has been focused on the compressive behavior DSTCs with UHPC. This paper presents an experimental study on the behavior of DSTCs with UHPC under concentric compression, with the studied parameters being the thickness of FRP tube, the steel fiber content of UHPC, the thickness of steel tube and the void ratio of DSTCs. It was found from the test that DSTCs with UHPC possessed high load-carrying capacity as well as excellent ductility, indicating it is a promising form for engineering use in practice.
{"title":"Compressive behavior of FRP-UHPC-steel double-skin tubular columns","authors":"J.J. Wang , X.F. Nie , L. Yang , W.G. Li , S.S. Zhang","doi":"10.1016/j.engstruct.2024.119451","DOIUrl":"10.1016/j.engstruct.2024.119451","url":null,"abstract":"<div><div>Hybrid fiber-reinforced polymer (FRP)-concrete-steel double-skin tubular columns (DSTCs) have been proved an effective structural form to achieve both high strength and ductility. While existing studies on such columns were mainly focused on the use of normal-strength/high-strength concrete as infilling materials, the use of ultra-high-performance concrete (UHPC) to improve the behavior of such columns is attracting increasing attention. For the same demand on load-carrying capacity, the use of UHPC in DSTCs can largely reduce the cross-sectional area and thus the weight of DSTCs, improving the seismic performance of DSTCs. On the other hand, the use of UHPC in DSTSs is able to achieve a much higher load-carrying capacity if the size of the compressive member is limited. To date, limited research has been focused on the compressive behavior DSTCs with UHPC. This paper presents an experimental study on the behavior of DSTCs with UHPC under concentric compression, with the studied parameters being the thickness of FRP tube, the steel fiber content of UHPC, the thickness of steel tube and the void ratio of DSTCs. It was found from the test that DSTCs with UHPC possessed high load-carrying capacity as well as excellent ductility, indicating it is a promising form for engineering use in practice.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"325 ","pages":"Article 119451"},"PeriodicalIF":5.6,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In regions prone to earthquakes, it is possible that reinforced concrete (RC) columns may experience multiple cycles of earthquake-induced damage and subsequent repair. Moreover, in practical situations, RC columns subjected to axial forces are often repaired without the use of temporary support systems to bear the weight of the superstructure, and frequently while residual drift remains. This study conducted cyclic loading tests and resin injection repair tests on RC columns twice to evaluate their seismic performance when repeatedly damaged and subsequently repaired. The resin injection repairs were performed with axial forces applied to the columns, considering the presence or absence of residual drift at the time of repair as an experimental factor. The results showed that although the resin injection repairs restored the maximum lateral load capacity of the columns to their original levels, the stiffness was not fully recovered. A significant finding was a 10 % to 20 % reduction in yield stiffness from the first to the second repair. Furthermore, incremental dynamic analyses were performed to investigate the effects of changes in lateral load capacity after resin injection repairs. The numerical results indicate that seismic response displacement increased significantly for small to moderate seismic motions due to resin injection repairs, while the response displacement at the ultimate level of the columns remained largely unaffected. Moreover, it was observed that the number of resin injection repairs and any asymmetry in seismic performance post-repair had a less substantial impact on the seismic response than the differences observed between as-built and repaired columns.
{"title":"Seismic performance of reinforced concrete column with repeated damage and repairs by resin injection","authors":"Keita Uemura , Kota Kadotani , Daiki Ichikawa , Genta Goto , Ryota Takahara , Yoshikazu Takahashi","doi":"10.1016/j.engstruct.2024.119463","DOIUrl":"10.1016/j.engstruct.2024.119463","url":null,"abstract":"<div><div>In regions prone to earthquakes, it is possible that reinforced concrete (RC) columns may experience multiple cycles of earthquake-induced damage and subsequent repair. Moreover, in practical situations, RC columns subjected to axial forces are often repaired without the use of temporary support systems to bear the weight of the superstructure, and frequently while residual drift remains. This study conducted cyclic loading tests and resin injection repair tests on RC columns twice to evaluate their seismic performance when repeatedly damaged and subsequently repaired. The resin injection repairs were performed with axial forces applied to the columns, considering the presence or absence of residual drift at the time of repair as an experimental factor. The results showed that although the resin injection repairs restored the maximum lateral load capacity of the columns to their original levels, the stiffness was not fully recovered. A significant finding was a 10 % to 20 % reduction in yield stiffness from the first to the second repair. Furthermore, incremental dynamic analyses were performed to investigate the effects of changes in lateral load capacity after resin injection repairs. The numerical results indicate that seismic response displacement increased significantly for small to moderate seismic motions due to resin injection repairs, while the response displacement at the ultimate level of the columns remained largely unaffected. Moreover, it was observed that the number of resin injection repairs and any asymmetry in seismic performance post-repair had a less substantial impact on the seismic response than the differences observed between as-built and repaired columns.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"325 ","pages":"Article 119463"},"PeriodicalIF":5.6,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-14DOI: 10.1016/j.engstruct.2024.119472
Yue Yu , You Chen , Wenjie Liao , Zihang Wang , Shulu Zhang , Yongjun Kang , Xinzheng Lu
The intelligent design of shear wall structures is a critical aspect of smart construction, with a high demand for research and applications. Accurately predicting the shear wall ratio (i.e., the shear wall area-to-floor area ratio) during cost estimation and rapidly generating shear wall layouts during early design is essential. However, the unclear influences of numerous design feature parameters hinder the enhancement of generative AI design. This affects both the prediction of shear wall ratios from multidimensional features and the generation of shear wall layouts from high-dimensional features. Therefore, a method for generating key structural design features using machine learning (ML) and generative adversarial networks (GANs), along with model interpretation, is proposed in this study. Existing shear wall design data are collected, and features such as the architectural plan geometry, seismic design conditions, and shear wall ratios are extracted to establish a dataset. Key shear wall ratio parameters are predicted using an ML model with multidimensional design features as inputs, and interpretability analysis is conducted using Shapley Additive Explanations (SHAP). Concurrently, a GAN model is built to generate shear wall designs using fused image-text high-dimensional features, and the influence patterns of design features are explained through sensitivity analysis. The analysis results indicate that the prediction accuracy is effectively enhanced by ML-based multidimensional feature learning, shear wall designs are effectively generated by GAN-based high-dimensional feature learning, and seismic design intensity and structural height are revealed as significant factors through interpretability analysis. Furthermore, when high-dimensional feature inputs are available, the generation of comprehensive features should be prioritized for shear wall structural designs.
{"title":"Intelligent generation and interpretability analysis of shear wall structure design by learning from multidimensional to high-dimensional features","authors":"Yue Yu , You Chen , Wenjie Liao , Zihang Wang , Shulu Zhang , Yongjun Kang , Xinzheng Lu","doi":"10.1016/j.engstruct.2024.119472","DOIUrl":"10.1016/j.engstruct.2024.119472","url":null,"abstract":"<div><div>The intelligent design of shear wall structures is a critical aspect of smart construction, with a high demand for research and applications. Accurately predicting the shear wall ratio (i.e., the shear wall area-to-floor area ratio) during cost estimation and rapidly generating shear wall layouts during early design is essential. However, the unclear influences of numerous design feature parameters hinder the enhancement of generative AI design. This affects both the prediction of shear wall ratios from multidimensional features and the generation of shear wall layouts from high-dimensional features. Therefore, a method for generating key structural design features using machine learning (ML) and generative adversarial networks (GANs), along with model interpretation, is proposed in this study. Existing shear wall design data are collected, and features such as the architectural plan geometry, seismic design conditions, and shear wall ratios are extracted to establish a dataset. Key shear wall ratio parameters are predicted using an ML model with multidimensional design features as inputs, and interpretability analysis is conducted using Shapley Additive Explanations (SHAP). Concurrently, a GAN model is built to generate shear wall designs using fused image-text high-dimensional features, and the influence patterns of design features are explained through sensitivity analysis. The analysis results indicate that the prediction accuracy is effectively enhanced by ML-based multidimensional feature learning, shear wall designs are effectively generated by GAN-based high-dimensional feature learning, and seismic design intensity and structural height are revealed as significant factors through interpretability analysis. Furthermore, when high-dimensional feature inputs are available, the generation of comprehensive features should be prioritized for shear wall structural designs.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"325 ","pages":"Article 119472"},"PeriodicalIF":5.6,"publicationDate":"2024-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-14DOI: 10.1016/j.engstruct.2024.119478
Zhan-Shuo Liang , Lin-Hai Han , Pu Wang
Experiments were conducted on 7 trussed concrete-filled steel tubular (CFST) hybrid structures subjected to pure bending, cross-sectional shape of chords, web types, yield strength of chord steel tube, and shear span ratio are the main parameters considered in the experimental work. Furthermore, the effects of these parameters on the flexural performance of the trussed structures were elucidated, and the load-strain relation and typical failure modes were summarized. A finite element analysis (FEA) modelling for trussed CFST hybrid structure subjected to bending was established and validated, the structural internal forces and stress distribution were revealed, and the criteria for determining the ultimate limit state was proposed. Based on parameter analysis, the key parameters affecting the flexural performance of the structure were determined, thereby the shear control factor was proposed. Finally, simplified calculating method for the bending resistance and the corresponding construction recommendations of trussed CFST hybrid structures were proposed.
{"title":"Performance and calculation of trussed concrete-filled steel tubular (CFST) hybrid structures subjected to bending","authors":"Zhan-Shuo Liang , Lin-Hai Han , Pu Wang","doi":"10.1016/j.engstruct.2024.119478","DOIUrl":"10.1016/j.engstruct.2024.119478","url":null,"abstract":"<div><div>Experiments were conducted on 7 trussed concrete-filled steel tubular (CFST) hybrid structures subjected to pure bending, cross-sectional shape of chords, web types, yield strength of chord steel tube, and shear span ratio are the main parameters considered in the experimental work. Furthermore, the effects of these parameters on the flexural performance of the trussed structures were elucidated, and the load-strain relation and typical failure modes were summarized. A finite element analysis (FEA) modelling for trussed CFST hybrid structure subjected to bending was established and validated, the structural internal forces and stress distribution were revealed, and the criteria for determining the ultimate limit state was proposed. Based on parameter analysis, the key parameters affecting the flexural performance of the structure were determined, thereby the shear control factor was proposed. Finally, simplified calculating method for the bending resistance and the corresponding construction recommendations of trussed CFST hybrid structures were proposed.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"325 ","pages":"Article 119478"},"PeriodicalIF":5.6,"publicationDate":"2024-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-13DOI: 10.1016/j.engstruct.2024.119464
Shuangbo Liu , Jian Feng , Jianguo Cai
Origami is widely studied for its excellent folding and deployment properties. This paper investigated the configuration design method of Miura thick panel origami inspired by kirigami. Firstly, a kirigami-inspired single-vertex four-crease(kiri-SF) unit is proposed and the folding process of the kiri-SF thick panel is analyzed. Secondly, the double-vertex eight-crease single-cutting(DES) loop unit is designed through mirror transformation, and the foldability conditions are obtained. Thirdly, three units inspired by classic Miura and general Miura were designed and the topologically connect method including merge, coalesce and replace were proposed to realize the single degree of freedom(single-DOF) cell. Then, four single-DOF cells are connected in an over-constrained form which is return link to realize a single-DOF topo-configuration. Meanwhile, three topo-configuration mock-ups were conducted and the relationship between thick panel Miura origami configuration and zero-thickness Miura origami configuration is investigated. Finally, the D-H Matrix analysis method in spatial mechanism theory is used to verify the relationship between geometric parameters and kinematic parameters, and the finite element method(FEM) is used to simulate the folding motion. The results show that the FEM simulation is in agreement with the actual motion state of the three topo-configurations.
{"title":"A configuration design method for kirigami-inspired Miura thick panel origami with single degree of freedom","authors":"Shuangbo Liu , Jian Feng , Jianguo Cai","doi":"10.1016/j.engstruct.2024.119464","DOIUrl":"10.1016/j.engstruct.2024.119464","url":null,"abstract":"<div><div>Origami is widely studied for its excellent folding and deployment properties. This paper investigated the configuration design method of Miura thick panel origami inspired by kirigami. Firstly, a kirigami-inspired single-vertex four-crease(kiri-SF) unit is proposed and the folding process of the kiri-SF thick panel is analyzed. Secondly, the double-vertex eight-crease single-cutting(DES) loop unit is designed through mirror transformation, and the foldability conditions are obtained. Thirdly, three units inspired by classic Miura and general Miura were designed and the topologically connect method including merge, coalesce and replace were proposed to realize the single degree of freedom(single-DOF) cell. Then, four single-DOF cells are connected in an over-constrained form which is return link to realize a single-DOF topo-configuration. Meanwhile, three topo-configuration mock-ups were conducted and the relationship between thick panel Miura origami configuration and zero-thickness Miura origami configuration is investigated. Finally, the D-H Matrix analysis method in spatial mechanism theory is used to verify the relationship between geometric parameters and kinematic parameters, and the finite element method(FEM) is used to simulate the folding motion. The results show that the FEM simulation is in agreement with the actual motion state of the three topo-configurations.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"325 ","pages":"Article 119464"},"PeriodicalIF":5.6,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-13DOI: 10.1016/j.engstruct.2024.119470
Qi Liao , Yuequan Bao , Haiyang Hu , Rongrong Hou
Digital twins are currently a research hotspot, of which efficient computation and real-time interaction are two key issues. However, for digital twinning of civil infrastructures, traditional computing methods are time-consuming, which prohibit their application to intensive and large-scale simulations. This paper proposes a mechanics-informed transformer-graph convolutional network (MI-TGCN) method for computing structural linear dynamic responses. A novel neural network architecture is designed through combining the transformer and GCN, in which mode-superposition method is innovatively integrated into the multi-head attention mechanism of the transformer to predict structural dynamic responses. Moreover, the adjacency matrix of GCN is replaced by the structural stiffness matrix because of their similarity in topological representation, which further forces structural dynamic responses to conform to the deformation compatibility principle. A five-story frame structure under seismic loads is employed as the numerical example to demonstrate the effectiveness of the proposed method. The results show that the proposed method not only achieves much higher computational efficiency but also predicts structural dynamic responses accurately. The proposed method runs an order of magnitude faster than the commonly used finite element methods.
{"title":"Mechanics-informed transformer-GCN for structural dynamic response prediction","authors":"Qi Liao , Yuequan Bao , Haiyang Hu , Rongrong Hou","doi":"10.1016/j.engstruct.2024.119470","DOIUrl":"10.1016/j.engstruct.2024.119470","url":null,"abstract":"<div><div>Digital twins are currently a research hotspot, of which efficient computation and real-time interaction are two key issues. However, for digital twinning of civil infrastructures, traditional computing methods are time-consuming, which prohibit their application to intensive and large-scale simulations. This paper proposes a mechanics-informed transformer-graph convolutional network (MI-TGCN) method for computing structural linear dynamic responses. A novel neural network architecture is designed through combining the transformer and GCN, in which mode-superposition method is innovatively integrated into the multi-head attention mechanism of the transformer to predict structural dynamic responses. Moreover, the adjacency matrix of GCN is replaced by the structural stiffness matrix because of their similarity in topological representation, which further forces structural dynamic responses to conform to the deformation compatibility principle. A five-story frame structure under seismic loads is employed as the numerical example to demonstrate the effectiveness of the proposed method. The results show that the proposed method not only achieves much higher computational efficiency but also predicts structural dynamic responses accurately. The proposed method runs an order of magnitude faster than the commonly used finite element methods.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"325 ","pages":"Article 119470"},"PeriodicalIF":5.6,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to accurately predict the static and dynamic behaviors of piezoelectric laminated composite (PLC) structures under thermo-electro-mechanical loads, this paper develops a comprehensive nonlinear model considering both geometric nonlinearity and piezoelectric material nonlinearity which includes strong electric field nonlinearity and temperature dependence. Based on piezoelectric nonlinear constitutive equations and von Kármán type geometric nonlinearity, the nonlinear governing equations of PLC beams under thermo-electro-mechanical loads are derived. The proposed nonlinear model is validated by numerical examples in this paper, and then the effects of geometric nonlinearity and material nonlinearity on static behavior, dynamic behavior, and active control of PLC beams are investigated. The results demonstrate that both geometric nonlinearity and material nonlinearity significantly impact the static and dynamic analysis of PLC beams. Therefore, both should be taken into account otherwise the structural behaviors cannot be predicted accurately, particularly under large thermo-electro-mechanical loads.
{"title":"Nonlinear thermo-electro-mechanical analysis of piezoelectric laminated composite beams considering strong electric field","authors":"Xuankai Guo , Yu Zhang , Yufan Wu , Yangyang Zhang , He Zhang , Chaofeng Lü","doi":"10.1016/j.engstruct.2024.119457","DOIUrl":"10.1016/j.engstruct.2024.119457","url":null,"abstract":"<div><div>In order to accurately predict the static and dynamic behaviors of piezoelectric laminated composite (PLC) structures under thermo-electro-mechanical loads, this paper develops a comprehensive nonlinear model considering both geometric nonlinearity and piezoelectric material nonlinearity which includes strong electric field nonlinearity and temperature dependence. Based on piezoelectric nonlinear constitutive equations and von Kármán type geometric nonlinearity, the nonlinear governing equations of PLC beams under thermo-electro-mechanical loads are derived. The proposed nonlinear model is validated by numerical examples in this paper, and then the effects of geometric nonlinearity and material nonlinearity on static behavior, dynamic behavior, and active control of PLC beams are investigated. The results demonstrate that both geometric nonlinearity and material nonlinearity significantly impact the static and dynamic analysis of PLC beams. Therefore, both should be taken into account otherwise the structural behaviors cannot be predicted accurately, particularly under large thermo-electro-mechanical loads.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"325 ","pages":"Article 119457"},"PeriodicalIF":5.6,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-12DOI: 10.1016/j.engstruct.2024.119443
María Rodríguez-Marcos , Paula Villanueva-Llaurado , Jaime Fernández-Gómez , Jorge López-Rebollo
Fibre reinforced cementitious matrix (FRCM) composites are suitable solutions for structural retrofitting of various materials due to their high strength-to-weight ratio and good compatibility. The mechanical performance of FRCM depends on the properties of the textile, of the mortar and the adherence between fibre and matrix and between matrix and substrate, thus requiring proper characterization of the interfacial behaviour. In this research, 16 concrete beams reinforced with 3 different single-layer and double-layer FRCM systems were subjected to three-point bending tests. The matrices were two enhanced mortars and a conventional mortar, and the textile was a bidirectional carbon grid. At the midspan, a 70 mm notch was performed and the internal rebars were disconnected, to isolate the performance of the FRCM. Strain was monitored during the test using Digital Image Correlation (DIC). Ultimate strength for beams with the same fibre volume varied by up to 60 % depending on the mortar, with a minimum ultimate load of twice that of the control beam. The beams with two textile layers had better performance, although the fibre exploitation ratio decreases with two layers. The ultimate strength of FRCM applied in beams is superior to that obtained in tensile tests for all the compared systems.
{"title":"Effectiveness of coated carbon fibre cementitious matrix systems for flexural strengthening of concrete beams","authors":"María Rodríguez-Marcos , Paula Villanueva-Llaurado , Jaime Fernández-Gómez , Jorge López-Rebollo","doi":"10.1016/j.engstruct.2024.119443","DOIUrl":"10.1016/j.engstruct.2024.119443","url":null,"abstract":"<div><div>Fibre reinforced cementitious matrix (FRCM) composites are suitable solutions for structural retrofitting of various materials due to their high strength-to-weight ratio and good compatibility. The mechanical performance of FRCM depends on the properties of the textile, of the mortar and the adherence between fibre and matrix and between matrix and substrate, thus requiring proper characterization of the interfacial behaviour. In this research, 16 concrete beams reinforced with 3 different single-layer and double-layer FRCM systems were subjected to three-point bending tests. The matrices were two enhanced mortars and a conventional mortar, and the textile was a bidirectional carbon grid. At the midspan, a 70 mm notch was performed and the internal rebars were disconnected, to isolate the performance of the FRCM. Strain was monitored during the test using Digital Image Correlation (DIC). Ultimate strength for beams with the same fibre volume varied by up to 60 % depending on the mortar, with a minimum ultimate load of twice that of the control beam. The beams with two textile layers had better performance, although the fibre exploitation ratio decreases with two layers. The ultimate strength of FRCM applied in beams is superior to that obtained in tensile tests for all the compared systems.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"325 ","pages":"Article 119443"},"PeriodicalIF":5.6,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-12DOI: 10.1016/j.engstruct.2024.119415
Qingshan Yang , Xiaorong Zeng , Kunpeng Guo , Shuyang Cao , Kai Wei , Wenshan Shan , Yukio Tamura
Flexible riser is prone to vortex-induced vibration (VIV), which can cause fatigue problems, making it essential to accurately estimate the VIV of the riser. The empirical wake-oscillator model is frequently used for VIV analysis, while the accuracy of the predicted response is not satisfactory in some cases, mainly due to its reliance on empirical parameters. To address these limitations, this study employs the wake-oscillator model developed by Tamura and Matsui, which provides a more explicit physical interpretation. Firstly, a set of interrelated partial differential equation is derived by integrating the wake-oscillator equations that characterize the flow with the structural motion equation that represent the riser’s movement. The effectiveness of the proposed method is validated by comparing the predicted outcomes (the displacement, dominant mode, and dominant frequency) with field and tank experiments. Additionally, space-time evolutions and spectral analysis were performed, and the energy conversion between the riser and the flow was examined to comprehend the physical mechanism of VIV of riser. Based on this, it was found that VIV of riser simultaneously exhibits traveling wave and standing wave characteristics. And there were also both mono-frequency and multi-frequency phenomena. Overall, the physically-meaningful model can accurately simulate the CF response of flexible riser, providing essential references for estimating its fatigue life, design, and operation of flexible risers.
{"title":"Analysis of vortex-induced vibration in flexible risers using a physically-meaningful wake-oscillator model","authors":"Qingshan Yang , Xiaorong Zeng , Kunpeng Guo , Shuyang Cao , Kai Wei , Wenshan Shan , Yukio Tamura","doi":"10.1016/j.engstruct.2024.119415","DOIUrl":"10.1016/j.engstruct.2024.119415","url":null,"abstract":"<div><div>Flexible riser is prone to vortex-induced vibration (VIV), which can cause fatigue problems, making it essential to accurately estimate the VIV of the riser. The empirical wake-oscillator model is frequently used for VIV analysis, while the accuracy of the predicted response is not satisfactory in some cases, mainly due to its reliance on empirical parameters. To address these limitations, this study employs the wake-oscillator model developed by Tamura and Matsui, which provides a more explicit physical interpretation. Firstly, a set of interrelated partial differential equation is derived by integrating the wake-oscillator equations that characterize the flow with the structural motion equation that represent the riser’s movement. The effectiveness of the proposed method is validated by comparing the predicted outcomes (the displacement, dominant mode, and dominant frequency) with field and tank experiments. Additionally, space-time evolutions and spectral analysis were performed, and the energy conversion between the riser and the flow was examined to comprehend the physical mechanism of VIV of riser. Based on this, it was found that VIV of riser simultaneously exhibits traveling wave and standing wave characteristics. And there were also both mono-frequency and multi-frequency phenomena. Overall, the physically-meaningful model can accurately simulate the CF response of flexible riser, providing essential references for estimating its fatigue life, design, and operation of flexible risers.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"325 ","pages":"Article 119415"},"PeriodicalIF":5.6,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-12DOI: 10.1016/j.engstruct.2024.119455
Kai Wang , Chuang Feng , Teng Yong Ng , Ding Zhou
This paper proposes a novel weak-form quadrature element method for analyzing defective sandwich beams with various boundary conditions. Discrete governing equation can be derived using Gauss-Lobatto points through the extended high-order sandwich panel theory and the energy variational principle. Based on the static equivalence principle, the unknown quantities at internal quadrature points can be determined using the physical quantities at endpoints while maintaining accuracy. This method significantly reduces the size of the modified element matrix, leading to a smaller global matrix. The proposed method is validated through dynamic and static numerical examples involving defective sandwich beams with different boundary conditions and geometric parameters. The results are compared with existing methods, demonstrating the rapid convergence and high accuracy of the proposed method in predicting displacements and stresses. The influence of defects on the mechanical behavior of sandwich beams is analyzed.
{"title":"Static and dynamic analysis of high-order defective sandwich beams by a novel weak-form quadrature element method","authors":"Kai Wang , Chuang Feng , Teng Yong Ng , Ding Zhou","doi":"10.1016/j.engstruct.2024.119455","DOIUrl":"10.1016/j.engstruct.2024.119455","url":null,"abstract":"<div><div>This paper proposes a novel weak-form quadrature element method for analyzing defective sandwich beams with various boundary conditions. Discrete governing equation can be derived using Gauss-Lobatto points through the extended high-order sandwich panel theory and the energy variational principle. Based on the static equivalence principle, the unknown quantities at internal quadrature points can be determined using the physical quantities at endpoints while maintaining accuracy. This method significantly reduces the size of the modified element matrix, leading to a smaller global matrix. The proposed method is validated through dynamic and static numerical examples involving defective sandwich beams with different boundary conditions and geometric parameters. The results are compared with existing methods, demonstrating the rapid convergence and high accuracy of the proposed method in predicting displacements and stresses. The influence of defects on the mechanical behavior of sandwich beams is analyzed.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"325 ","pages":"Article 119455"},"PeriodicalIF":5.6,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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