Pub Date : 2025-03-12DOI: 10.1016/j.engstruct.2025.120033
Feng Wu, Yuxiang Yang, Li Zhu, Chen Li, Yuelin Zhao
In engineering, the widespread uncertainty variables may endanger structural safety. Constructing a model to accurately describe time-variant epistemic uncertainty variables with stationary characters has been a challenge. To address the issue, this paper introduces the concept of a minimum interval radius-based stationary interval process model (MIR-SIPM), whose construction is essentially a constrained optimization problem. Moreover, this paper proposes two methods to eliminate the constraints in the optimization problem corresponding to the construction of MIR-SIPM, presenting two unconstrained optimization problems to construct MIR-SIPM efficiently. Through numerical experiments, the accuracy and efficiency of the proposed methods in describing the uncertainty variables and information are validated.
{"title":"Efficient construction methods for the minimum interval radius-based stationary interval process model","authors":"Feng Wu, Yuxiang Yang, Li Zhu, Chen Li, Yuelin Zhao","doi":"10.1016/j.engstruct.2025.120033","DOIUrl":"10.1016/j.engstruct.2025.120033","url":null,"abstract":"<div><div>In engineering, the widespread uncertainty variables may endanger structural safety. Constructing a model to accurately describe time-variant epistemic uncertainty variables with stationary characters has been a challenge. To address the issue, this paper introduces the concept of a minimum interval radius-based stationary interval process model (MIR-SIPM), whose construction is essentially a constrained optimization problem. Moreover, this paper proposes two methods to eliminate the constraints in the optimization problem corresponding to the construction of MIR-SIPM, presenting two unconstrained optimization problems to construct MIR-SIPM efficiently. Through numerical experiments, the accuracy and efficiency of the proposed methods in describing the uncertainty variables and information are validated.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"332 ","pages":"Article 120033"},"PeriodicalIF":5.6,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609817","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 : 2025-03-12DOI: 10.1016/j.engstruct.2025.120070
Kang Wang , Xu-Hong Zhou , Jian-Ting Zhou , Ji-Ke Tan , Yu-Hang Wang , Jing-Zhou Xin
To investigate the fatigue performance of multiplanar concrete-filled steel tubular (CFST) KK-joints with internal ring stiffeners, stress concentration factors (SCFs) static tests were conducted on eight specimens with comparison parameters including β, γ, and τ. The loading conditions included both single-brace and combined-braces loading conditions. The experimental findings indicated that, under single-brace loading conditions, significant structural stress still present at the weld toes along the intersection lines of the non-loaded braces. To quantify this effect, this study introduced the multiplanar influence factors (MIFs), derived from the SCFs definition. The influence of various parameters on the SCFs and MIFs of the joints was analyzed. Based on the test results, calculation formulas for the distribution curves of the multiplanar stress concentration factor (SCFMP) and combined hot-spot stresses of multiplanar CFST KK-joints with internal ring stiffeners under random complex loading conditions were proposed.
{"title":"Experimental study on stress concentration factors of multiplanar concrete-filled steel tubular KK-joints with internal ring stiffeners","authors":"Kang Wang , Xu-Hong Zhou , Jian-Ting Zhou , Ji-Ke Tan , Yu-Hang Wang , Jing-Zhou Xin","doi":"10.1016/j.engstruct.2025.120070","DOIUrl":"10.1016/j.engstruct.2025.120070","url":null,"abstract":"<div><div>To investigate the fatigue performance of multiplanar concrete-filled steel tubular (CFST) KK-joints with internal ring stiffeners, stress concentration factors (SCFs) static tests were conducted on eight specimens with comparison parameters including <em>β</em>, <em>γ</em>, and <em>τ</em>. The loading conditions included both single-brace and combined-braces loading conditions. The experimental findings indicated that, under single-brace loading conditions, significant structural stress still present at the weld toes along the intersection lines of the non-loaded braces. To quantify this effect, this study introduced the multiplanar influence factors (MIFs), derived from the SCFs definition. The influence of various parameters on the SCFs and MIFs of the joints was analyzed. Based on the test results, calculation formulas for the distribution curves of the multiplanar stress concentration factor (SCF<sub>MP</sub>) and combined hot-spot stresses of multiplanar CFST KK-joints with internal ring stiffeners under random complex loading conditions were proposed.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"332 ","pages":"Article 120070"},"PeriodicalIF":5.6,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609917","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 : 2025-03-11DOI: 10.1016/j.engstruct.2025.120028
Tao Yang , Zixi Huang , Jiaheng Xie , Jiayi Liu , Shiyang Li , Bolong Jiang , Guanglan Zhu , Xingjian Jing
This paper proposes a double nonlinear stiffness vibration isolator (DNSVI) with gear-driven electromagnetic energy harvester (GEEH) for integration of vibration isolation and energy harvesting. DNSVI is composed of oblique spring structure and rhomboid structure both of which contribute to its nonlinear stiffness. Through a detailed investigation of the influence of structural parameters, the optimal quasi-zero stiffness condition can be achieved. The dynamic model has been developed, the force transmission rate is calculated by using the multi-scale method. The impacts of varying excitation amplitudes, damping and asymmetry on the force transmission rate are explored. More importantly, the GEEH is designed utilizing gear transmission mechanisms and electromagnetic energy harvesting technologies. The vibration isolation capabilities and energy harvesting efficiency of the DNSVI-GEEH are experimentally verified. The initial vibration isolation frequency is 3 Hz, and the peak power is 25 mW when the excitation frequency is 4.5 Hz, with an external 250 resistor. Thus, the DNSVI-GEEH offers a novel approach to achieving low-frequency vibration isolation and energy harvesting.
{"title":"Dynamic analysis and energy harvesting of double nonlinear stiffness vibration isolator","authors":"Tao Yang , Zixi Huang , Jiaheng Xie , Jiayi Liu , Shiyang Li , Bolong Jiang , Guanglan Zhu , Xingjian Jing","doi":"10.1016/j.engstruct.2025.120028","DOIUrl":"10.1016/j.engstruct.2025.120028","url":null,"abstract":"<div><div>This paper proposes a double nonlinear stiffness vibration isolator (DNSVI) with gear-driven electromagnetic energy harvester (GEEH) for integration of vibration isolation and energy harvesting. DNSVI is composed of oblique spring structure and rhomboid structure both of which contribute to its nonlinear stiffness. Through a detailed investigation of the influence of structural parameters, the optimal quasi-zero stiffness condition can be achieved. The dynamic model has been developed, the force transmission rate is calculated by using the multi-scale method. The impacts of varying excitation amplitudes, damping and asymmetry on the force transmission rate are explored. More importantly, the GEEH is designed utilizing gear transmission mechanisms and electromagnetic energy harvesting technologies. The vibration isolation capabilities and energy harvesting efficiency of the DNSVI-GEEH are experimentally verified. The initial vibration isolation frequency is 3 Hz, and the peak power is 25 mW when the excitation frequency is 4.5 Hz, with an external 250<span><math><mi>Ω</mi></math></span> resistor. Thus, the DNSVI-GEEH offers a novel approach to achieving low-frequency vibration isolation and energy harvesting.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"332 ","pages":"Article 120028"},"PeriodicalIF":5.6,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143592828","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 : 2025-03-11DOI: 10.1016/j.engstruct.2025.120035
Bahram Mirzaie Abar, Mario D’Aniello, Raffaele Landolfo
This paper presents a proposal of extension of the second-generation EC8 concepts of steel moment-resisting connection to AISC-like design criteria for the case of stainless steel end-plate connections. Both full strength (i.e., non-yielding connection) and equal strength (i.e., balance yielding in the beam and connection) are considered. The design yield patterns of both end-plate and column flange are revised in order to enhance the local ductility of the connections. In addition, further rules for stainless steel bolts are proposed, and depth-to-thickness ratios for the rib stiffener are established. The effectiveness of the design procedure is verified through parametric finite element (FE) simulations that were performed using models validated against three experimental tests on stainless steel connections. Besides the evaluation of the monotonic and cyclic response, an extensive damage assessment was conducted. The results indicated that the proposed design criteria allow for designing connections that experience the expected mechanical response.
{"title":"An extension of EC8-concepts to AISC-like design criteria for ductile stainless steel end-plate moment connections","authors":"Bahram Mirzaie Abar, Mario D’Aniello, Raffaele Landolfo","doi":"10.1016/j.engstruct.2025.120035","DOIUrl":"10.1016/j.engstruct.2025.120035","url":null,"abstract":"<div><div>This paper presents a proposal of extension of the second-generation EC8 concepts of steel moment-resisting connection to AISC-like design criteria for the case of stainless steel end-plate connections. Both full strength (i.e., non-yielding connection) and equal strength (i.e., balance yielding in the beam and connection) are considered. The design yield patterns of both end-plate and column flange are revised in order to enhance the local ductility of the connections. In addition, further rules for stainless steel bolts are proposed, and depth-to-thickness ratios for the rib stiffener are established. The effectiveness of the design procedure is verified through parametric finite element (FE) simulations that were performed using models validated against three experimental tests on stainless steel connections. Besides the evaluation of the monotonic and cyclic response, an extensive damage assessment was conducted. The results indicated that the proposed design criteria allow for designing connections that experience the expected mechanical response.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"332 ","pages":"Article 120035"},"PeriodicalIF":5.6,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143593351","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 : 2025-03-11DOI: 10.1016/j.engstruct.2025.120022
Yuhong Yan, Pengpeng Wang, Yiyan Lu, Caiwang Tai, Xiaobo Zhao
This study investigated the slenderness effect on circular RC columns strengthened with post-cast self-compacting concrete filled square steel tubes under axial compression. A total of 36 specimens, comprising 4 un-strengthened circular RC columns and 32 strengthened columns, were fabricated and tested. Parameters including the length-to-width (L/B) ratio, strength of the post-cast self-compacting concrete, and width-to-thickness ratio of the steel tube were investigated. Experimental results indicated that the load-bearing capacity and ductility of the columns were significantly enhanced after strengthening. As L/B ratio increased (with B constant), the failure mode of the strengthened columns transitioned from strength failure to instability failure. Columns with L/B ratios of 3.0 and 6.0 had similar load-bearing capacity and ductility. As L/B ratio rose to 8.0, the load-bearing capacity slightly decreased, while ductility significantly decreased. With an L/B ratio of 10.0, both load-bearing capacity and ductility showed a pronounced decrease. Increasing the L/B ratio caused greater uneven stress distribution in the post-cast concrete, resulting in a substantial decrease in its bearing load. This is the main factor leading to the reduced load-bearing capacity of the strengthened columns. By introducing the equivalent concrete strength and the equivalent confining coefficient, calculation formulas were proposed to predict the load-bearing capacity of the strengthened columns.
{"title":"Slenderness effect on circular RC columns strengthened with post-cast self-compacting concrete filled square steel tubes","authors":"Yuhong Yan, Pengpeng Wang, Yiyan Lu, Caiwang Tai, Xiaobo Zhao","doi":"10.1016/j.engstruct.2025.120022","DOIUrl":"10.1016/j.engstruct.2025.120022","url":null,"abstract":"<div><div>This study investigated the slenderness effect on circular RC columns strengthened with post-cast self-compacting concrete filled square steel tubes under axial compression. A total of 36 specimens, comprising 4 un-strengthened circular RC columns and 32 strengthened columns, were fabricated and tested. Parameters including the length-to-width (<em>L</em>/<em>B</em>) ratio, strength of the post-cast self-compacting concrete, and width-to-thickness ratio of the steel tube were investigated. Experimental results indicated that the load-bearing capacity and ductility of the columns were significantly enhanced after strengthening. As <em>L</em>/<em>B</em> ratio increased (with <em>B</em> constant), the failure mode of the strengthened columns transitioned from strength failure to instability failure. Columns with <em>L</em>/<em>B</em> ratios of 3.0 and 6.0 had similar load-bearing capacity and ductility. As <em>L</em>/<em>B</em> ratio rose to 8.0, the load-bearing capacity slightly decreased, while ductility significantly decreased. With an <em>L</em>/<em>B</em> ratio of 10.0, both load-bearing capacity and ductility showed a pronounced decrease. Increasing the <em>L</em>/<em>B</em> ratio caused greater uneven stress distribution in the post-cast concrete, resulting in a substantial decrease in its bearing load. This is the main factor leading to the reduced load-bearing capacity of the strengthened columns. By introducing the equivalent concrete strength and the equivalent confining coefficient, calculation formulas were proposed to predict the load-bearing capacity of the strengthened columns.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"332 ","pages":"Article 120022"},"PeriodicalIF":5.6,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143593395","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 : 2025-03-11DOI: 10.1016/j.engstruct.2025.120045
Hao Liu , Zengshen Yue , Rui Zhang , Jiawei Lu , Jian Zhu
The threat of blasts has a devastating effect on vehicles, buildings, and even human lives, creating a pressing need for the development of blast protection systems. A novel multi-layered kirigami corrugated (MKC) sandwich panel has been proposed, featuring kirigami corrugated cores with different geometries in layers while maintaining the same mass, to investigate its blast-resistance performance. The dynamic response of MKC sandwich panels in seven configurations subjected to blast loading was numerically studied via finite element simulations, with their dynamic deformation evolution, deformation/failure modes, panel deflections, and core compression systematically analyzed. The results indicate that the dynamic deformation process of MKC sandwich panels can be approximately decoupled into four stages. The deformation and failure modes of the panels and the formation of plastic hinges in each part of the cell were further analyzed. Moreover, rear panel deflections are found to be significantly influenced by the multi-layer arrangement of the structure. Compared with the original configuration, adjusting the core layer configuration could reduce the peak deflection by 41 %, indicating the ability of multi-layer design to regulate the structural blast resistance. Designing the core at the rear side to be stronger significantly improves the structure’s blast resistance. Subsequently, the response of MKC sandwich panels was modeled using a surrogate modeling technique, with its model accuracy validated. A high-efficiency optimization procedure factoring structural deformation resistance and energy absorption performance of the MKC sandwich panels was proposed by coupling the surrogate model with the NSGA-II algorithm. The optimal sandwich panel has a reduced rear panel peak deformation by up to 55.7 % while increasing specific energy absorption by approximately 15.8 % compared with the preliminary design. This optimized core layer arrangement strategy can significantly enhance the performance of multi-layer structures, while ensuring the convenience of fabrication and improving the material utilization efficiency.
{"title":"Blast response and multi-objective optimization of multi-layered kirigami corrugated sandwich panels","authors":"Hao Liu , Zengshen Yue , Rui Zhang , Jiawei Lu , Jian Zhu","doi":"10.1016/j.engstruct.2025.120045","DOIUrl":"10.1016/j.engstruct.2025.120045","url":null,"abstract":"<div><div>The threat of blasts has a devastating effect on vehicles, buildings, and even human lives, creating a pressing need for the development of blast protection systems. A novel multi-layered kirigami corrugated (MKC) sandwich panel has been proposed, featuring kirigami corrugated cores with different geometries in layers while maintaining the same mass, to investigate its blast-resistance performance. The dynamic response of MKC sandwich panels in seven configurations subjected to blast loading was numerically studied via finite element simulations, with their dynamic deformation evolution, deformation/failure modes, panel deflections, and core compression systematically analyzed. The results indicate that the dynamic deformation process of MKC sandwich panels can be approximately decoupled into four stages. The deformation and failure modes of the panels and the formation of plastic hinges in each part of the cell were further analyzed. Moreover, rear panel deflections are found to be significantly influenced by the multi-layer arrangement of the structure. Compared with the original configuration, adjusting the core layer configuration could reduce the peak deflection by 41 %, indicating the ability of multi-layer design to regulate the structural blast resistance. Designing the core at the rear side to be stronger significantly improves the structure’s blast resistance. Subsequently, the response of MKC sandwich panels was modeled using a surrogate modeling technique, with its model accuracy validated. A high-efficiency optimization procedure factoring structural deformation resistance and energy absorption performance of the MKC sandwich panels was proposed by coupling the surrogate model with the NSGA-II algorithm. The optimal sandwich panel has a reduced rear panel peak deformation by up to 55.7 % while increasing specific energy absorption by approximately 15.8 % compared with the preliminary design. This optimized core layer arrangement strategy can significantly enhance the performance of multi-layer structures, while ensuring the convenience of fabrication and improving the material utilization efficiency.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"332 ","pages":"Article 120045"},"PeriodicalIF":5.6,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143592765","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 : 2025-03-11DOI: 10.1016/j.engstruct.2025.120067
Nuoxin Wu, Gaoming Zhu, Kang Hai Tan
Concrete-encased concrete-filled steel tube (CECFST) columns are widely recognised for their superior structural performance in mega construction structures. Despite extensive research under normal conditions, limited attention has been given to their performance in fire conditions. In this study, five CECFST slender columns were tested under transient fire conditions to investigate their fire behaviour. Key test findings included the failure mode, temperature distribution, structural response and fire resistance. Experimental results revealed that fire-exposed CECFST columns generally showed global buckling accompanied by extensive tensile cracking, demonstrating excellent ductility. Explosive spalling was observed in two specimens despite adding 0.2 vol% PP fibres. Moreover, compared to conventional concrete-filled steel tube (CFST) columns, CECFST columns exhibited superior fire resistance, highlighting their effectiveness as a ductile structural member under fire exposure. In addition, a calculation model was developed based on finite difference method (FDM) to predict the temperature distribution and strength reduction for CECFST columns in fire conditions. The calculation model can be easily implemented via MATLAB, and the code is open source. The proposed model was verified with test results, showing reasonable accuracy. This study provides insights and practical tool for evaluating fire performance of CECFST columns, particularly in super high-rise buildings and infrastructure projects where the maximum fire resistance may be required by the code.
{"title":"Fire behaviour of pin-ended concrete-encased concrete-filled steel tube (CECFST) slender columns under concentric and eccentric compression","authors":"Nuoxin Wu, Gaoming Zhu, Kang Hai Tan","doi":"10.1016/j.engstruct.2025.120067","DOIUrl":"10.1016/j.engstruct.2025.120067","url":null,"abstract":"<div><div>Concrete-encased concrete-filled steel tube (CECFST) columns are widely recognised for their superior structural performance in mega construction structures. Despite extensive research under normal conditions, limited attention has been given to their performance in fire conditions. In this study, five CECFST slender columns were tested under transient fire conditions to investigate their fire behaviour. Key test findings included the failure mode, temperature distribution, structural response and fire resistance. Experimental results revealed that fire-exposed CECFST columns generally showed global buckling accompanied by extensive tensile cracking, demonstrating excellent ductility. Explosive spalling was observed in two specimens despite adding 0.2 vol% PP fibres. Moreover, compared to conventional concrete-filled steel tube (CFST) columns, CECFST columns exhibited superior fire resistance, highlighting their effectiveness as a ductile structural member under fire exposure. In addition, a calculation model was developed based on finite difference method (FDM) to predict the temperature distribution and strength reduction for CECFST columns in fire conditions. The calculation model can be easily implemented via MATLAB, and the code is open source. The proposed model was verified with test results, showing reasonable accuracy. This study provides insights and practical tool for evaluating fire performance of CECFST columns, particularly in super high-rise buildings and infrastructure projects where the maximum fire resistance may be required by the code.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"332 ","pages":"Article 120067"},"PeriodicalIF":5.6,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143592831","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 : 2025-03-11DOI: 10.1016/j.engstruct.2025.120048
Haojie Huang, Shuang Zhang, Yongquan Li
Origami-inspired structures have driven the development of metamaterials with specialized mechanical performance. Although several design methods exist for origami metamaterials, performance-oriented inverse design remains to be accomplished. This study introduces a performance-oriented inverse design method for constructing cellular metamaterials. First, a novel thick-panel origami structure is proposed and modified, which is demonstrated to have a single degree-of-freedom using screw theory. Subsequently, the topological geometry of the improved structure is analyzed, revealing a negative Poisson’s ratio. Leveraging this property, a class of metamaterial cells and their corresponding cellular metamaterials are inverse-designed, with the thick-panel origami regarded as a rectangular block. This performance-oriented inverse design approach provides a novel perspective for constructing cellular metamaterials.
{"title":"Inverse design of performance-oriented cellular metamaterials","authors":"Haojie Huang, Shuang Zhang, Yongquan Li","doi":"10.1016/j.engstruct.2025.120048","DOIUrl":"10.1016/j.engstruct.2025.120048","url":null,"abstract":"<div><div>Origami-inspired structures have driven the development of metamaterials with specialized mechanical performance. Although several design methods exist for origami metamaterials, performance-oriented inverse design remains to be accomplished. This study introduces a performance-oriented inverse design method for constructing cellular metamaterials. First, a novel thick-panel origami structure is proposed and modified, which is demonstrated to have a single degree-of-freedom using screw theory. Subsequently, the topological geometry of the improved structure is analyzed, revealing a negative Poisson’s ratio. Leveraging this property, a class of metamaterial cells and their corresponding cellular metamaterials are inverse-designed, with the thick-panel origami regarded as a rectangular block. This performance-oriented inverse design approach provides a novel perspective for constructing cellular metamaterials.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"332 ","pages":"Article 120048"},"PeriodicalIF":5.6,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143592766","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 : 2025-03-11DOI: 10.1016/j.engstruct.2025.120019
Mohammed Gamal Gouda , Ibrahim T. Mostafa , Hamdy M. Mohamed , Alaa Sherif , Mohamed H. Agamy
To date, the combined shear and torsional behavior of reinforced concrete (RC) beams reinforced with continuous glass-fiber reinforced polymer (GFRP) spiral stirrups has not been thoroughly investigated. Accordingly, this paper investigates the behavior of RC beams reinforced with GFRP bars and rectangular continuous spirals under combined shear and torsion. The experimental program involved testing six RC beams, each measuring 3000 mm in length, 200 mm in width, and 400 mm in depth. The test parameters focused on the configuration of transverse reinforcement (GFRP spirals versus GFRP tie stirrups) and varying transverse reinforcement ratios. Four specimens were reinforced with GFRP spirals at different reinforcement ratios to assess the effect of transverse reinforcement on shear and torsional capacities. One specimen was reinforced with GFRP tie stirrups to investigate the influence of stirrup configuration, and one specimen was without web reinforcement (control) to evaluate the impact of concrete strength on the capacities. Experimental results showed that beams with GFRP spirals or tie stirrups failed due to the progressive widening of diagonal tension cracks and subsequent rupture of the GFRP reinforcement at bent portions, while the control beam failed due to concrete splitting. The results demonstrated that reducing the spacing of GFRP spirals significantly enhanced shear and torsional capacities. The experimental findings were compared with existing design codes and a newly proposed model based on the space truss analogy.
{"title":"Understanding the impact of spiral reinforcement on GFRP-RC beams under combined shear and torsion loading","authors":"Mohammed Gamal Gouda , Ibrahim T. Mostafa , Hamdy M. Mohamed , Alaa Sherif , Mohamed H. Agamy","doi":"10.1016/j.engstruct.2025.120019","DOIUrl":"10.1016/j.engstruct.2025.120019","url":null,"abstract":"<div><div>To date, the combined shear and torsional behavior of reinforced concrete (RC) beams reinforced with continuous glass-fiber reinforced polymer (GFRP) spiral stirrups has not been thoroughly investigated. Accordingly, this paper investigates the behavior of RC beams reinforced with GFRP bars and rectangular continuous spirals under combined shear and torsion. The experimental program involved testing six RC beams, each measuring 3000 mm in length, 200 mm in width, and 400 mm in depth. The test parameters focused on the configuration of transverse reinforcement (GFRP spirals versus GFRP tie stirrups) and varying transverse reinforcement ratios. Four specimens were reinforced with GFRP spirals at different reinforcement ratios to assess the effect of transverse reinforcement on shear and torsional capacities. One specimen was reinforced with GFRP tie stirrups to investigate the influence of stirrup configuration, and one specimen was without web reinforcement (control) to evaluate the impact of concrete strength on the capacities. Experimental results showed that beams with GFRP spirals or tie stirrups failed due to the progressive widening of diagonal tension cracks and subsequent rupture of the GFRP reinforcement at bent portions, while the control beam failed due to concrete splitting. The results demonstrated that reducing the spacing of GFRP spirals significantly enhanced shear and torsional capacities. The experimental findings were compared with existing design codes and a newly proposed model based on the space truss analogy.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"332 ","pages":"Article 120019"},"PeriodicalIF":5.6,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143592763","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 : 2025-03-11DOI: 10.1016/j.engstruct.2025.120036
Mattia Debertolis , Yue Wang , Tianxiang Wang , Roberto Crocetti , Magnus Wålinder
Previous studies have demonstrated the potential of birch plywood as a substitute for steel plates in multi-plane shear connections of timber structures due to, among other things, its low environmental impact, better workability, and relatively low cost. However, models in modern building codes, such as Eurocode EN1995–1 (EC5), can be used to determine the load-carrying capacity of timber connections with up to two shear planes. Furthermore, some studies have shown that EC5 design model tend to underestimate the actual load-carrying capacity of timber connections. Therefore, there are some uncertainties concerning suitable design models to assess the load-carrying capacity of such connections. This study was preliminary conducted to shed light on the reasons for such discrepancies, conducting several experiments on both doweled and screwed birch plywood-to-timber connections, with either two or four shear planes. The analytical load-carrying capacities estimated by EC5 showed underestimation of the experimental results, with greater underestimation when fully threaded screws are adopted as fasteners, rather than smooth dowels. Furthermore, regardless of the type of fastener, a substantial discrepancy between EC5’s prediction and experimental results was observed when the number of shear planes was increased from two to four. The results of the investigations indicate that the main cause of the discrepancies might be associated with the so-called “rope effect” which is taken into account by EC5’s design approach in an over-conservative manner.
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