Pub Date : 2024-10-09DOI: 10.1016/j.compstruc.2024.107556
Zitong Wang , Qilin Li , Wensu Chen , Hong Hao , Ling Li
Reinforced concrete (RC) walls are vulnerable to severe damage under high-intensity, close-in TNT explosions. Substantial secondary fragments at high ejecting velocities could be generated from the damaged wall, posing serious threats to people, facilities and structures in the area. Predicting the blast-induced secondary fragments remains a great challenge. Traditional computational methods, such as the finite element method (FEM) or meshfree methods, are often used to predict the fragment characteristics despite their inherent problems, such as the application of erosion and predefining the weak sections in the simulation. They also require high computational power to perform the simulation, thus limiting their use in creating an adequate dataset to thoroughly analyse the characteristics of secondary fragments and the associated threats. This study employs a recently developed machine learning-based approach named Fragment Graph Network (FGN), a variant of Graph Neural Networks (GNNs), to generate a large dataset of fragment characteristics. This FGN model can efficiently predict the fragment mass, size, and velocity with a significantly reduced computational cost. Intensive predictions of fragments from different wall configurations and explosion intensities are carried out. The results are used to develop analytical formulae for predicting secondary fragments of RC walls subjected to close-in explosions.
{"title":"Fragment prediction of reinforced concrete wall under close-in explosion using Fragment Graph Network (FGN)","authors":"Zitong Wang , Qilin Li , Wensu Chen , Hong Hao , Ling Li","doi":"10.1016/j.compstruc.2024.107556","DOIUrl":"10.1016/j.compstruc.2024.107556","url":null,"abstract":"<div><div>Reinforced concrete (RC) walls are vulnerable to severe damage under high-intensity, close-in TNT explosions. Substantial secondary fragments at high ejecting velocities could be generated from the damaged wall, posing serious threats to people, facilities and structures in the area. Predicting the blast-induced secondary fragments remains a great challenge. Traditional computational methods, such as the finite element method (FEM) or meshfree methods, are often used to predict the fragment characteristics despite their inherent problems, such as the application of erosion and predefining the weak sections in the simulation. They also require high computational power to perform the simulation, thus limiting their use in creating an adequate dataset to thoroughly analyse the characteristics of secondary fragments and the associated threats. This study employs a recently developed machine learning-based approach named Fragment Graph Network (FGN), a variant of Graph Neural Networks (GNNs), to generate a large dataset of fragment characteristics. This FGN model can efficiently predict the fragment mass, size, and velocity with a significantly reduced computational cost. Intensive predictions of fragments from different wall configurations and explosion intensities are carried out. The results are used to develop analytical formulae for predicting secondary fragments of RC walls subjected to close-in explosions.</div></div>","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"305 ","pages":"Article 107556"},"PeriodicalIF":4.4,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-10-05DOI: 10.1016/j.compstruc.2024.107560
Marcin Kamiński , Rafał Bredow
The main research problem studied in this work is an uncertain response and reliability assessment of the spatial cable structures due to the environmental stochasticity as well as material and geometrical imperfections. Some popular cable structures are analyzed for this purpose using the Stochastic Finite Element Method (SFEM) implemented with the use of three different techniques, namely the iterative generalized perturbation method, semi-analytical approach as well as the Monte-Carlo simulation. Uncertainty quantification delivered in this study is based on the series of FEM analyses of both static and dynamic structural problems. They enable the Least Squares Method determination of the structural polynomial responses linking extreme stresses and deformations with several uncorrelated uncertainty sources. Reliability assessment, fundamental in durability and Structural Health Monitoring, is completed using a comparison of the First Order Reliability Method (FORM) with probabilistic distance formulated by Bhattacharyya. Input uncertainties are assumed to be Gaussian according to the Maximum Entropy Principle. They have specific expected values following engineering design demands or the provisions of designing codes, whereas their standard deviations do not exceed the 10% level. The methods presented and the results obtained in this study may serve for further reliability analyses of large-scale civil engineering structures completed with both steel cables and also reinforced concrete plates like suspended bridges, for instance.
{"title":"On application of the relative entropy concept in reliability assessment of some engineering cable structures","authors":"Marcin Kamiński , Rafał Bredow","doi":"10.1016/j.compstruc.2024.107560","DOIUrl":"10.1016/j.compstruc.2024.107560","url":null,"abstract":"<div><div>The main research problem studied in this work is an uncertain response and reliability assessment of the spatial cable structures due to the environmental stochasticity as well as material and geometrical imperfections. Some popular cable structures are analyzed for this purpose using the Stochastic Finite Element Method (SFEM) implemented with the use of three different techniques, namely the iterative generalized perturbation method, semi-analytical approach as well as the Monte-Carlo simulation. Uncertainty quantification delivered in this study is based on the series of FEM analyses of both static and dynamic structural problems. They enable the Least Squares Method determination of the structural polynomial responses linking extreme stresses and deformations with several uncorrelated uncertainty sources. Reliability assessment, fundamental in durability and Structural Health Monitoring, is completed using a comparison of the First Order Reliability Method (FORM) with probabilistic distance formulated by Bhattacharyya. Input uncertainties are assumed to be Gaussian according to the Maximum Entropy Principle. They have specific expected values following engineering design demands or the provisions of designing codes, whereas their standard deviations do not exceed the 10% level. The methods presented and the results obtained in this study may serve for further reliability analyses of large-scale civil engineering structures completed with both steel cables and also reinforced concrete plates like suspended bridges, for instance.</div></div>","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"305 ","pages":"Article 107560"},"PeriodicalIF":4.4,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-10-04DOI: 10.1016/j.compstruc.2024.107558
Germán Nanclares, Oscar Curadelli, Daniel Ambrosini
This paper investigates the influence of vertical seismic accelerations on the seismic response of RC bridges through numerical simulations using an enhanced non-linear numerical model. Results confirm that the incorporation of vertical accelerations, either through actual records or scaled horizontal records, can considerably modify the seismic response and the collapse mechanism. In the case of actual vertical records, the vertical component significantly contributes to premature structural deterioration, intensifying demand and accelerating failure mechanisms. On the other hand, the study underscores the inadequacy of using scaled horizontal records to represent vertical accelerations, as suggested by some seismic codes, as it not only distorts seismic response evaluation but also alters failure modes. The analysis of vertical vibration reveals higher displacements, increasing flexural demand on the deck, and leading to a progressive loss of vertical support at the central column. The research establishes the need to accurately account for vertical seismic accelerations in bridge design evaluations, as their impact on structural response and failure mechanisms cannot be underestimated. The work highlights the importance of a highly detailed 3D numerical model in assessing traditional parameters and capturing complex collapse mechanisms arising from material and geometric nonlinearities.
{"title":"Influence of the vertical seismic component on the response of continuous RC bridges","authors":"Germán Nanclares, Oscar Curadelli, Daniel Ambrosini","doi":"10.1016/j.compstruc.2024.107558","DOIUrl":"10.1016/j.compstruc.2024.107558","url":null,"abstract":"<div><div>This paper investigates the influence of vertical seismic accelerations on the seismic response of RC bridges through numerical simulations using an enhanced non-linear numerical model. Results confirm that the incorporation of vertical accelerations, either through actual records or scaled horizontal records, can considerably modify the seismic response and the collapse mechanism. In the case of actual vertical records, the vertical component significantly contributes to premature structural deterioration, intensifying demand and accelerating failure mechanisms. On the other hand, the study underscores the inadequacy of using scaled horizontal records to represent vertical accelerations, as suggested by some seismic codes, as it not only distorts seismic response evaluation but also alters failure modes. The analysis of vertical vibration reveals higher displacements, increasing flexural demand on the deck, and leading to a progressive loss of vertical support at the central column. The research establishes the need to accurately account for vertical seismic accelerations in bridge design evaluations, as their impact on structural response and failure mechanisms cannot be underestimated. The work highlights the importance of a highly detailed 3D numerical model in assessing traditional parameters and capturing complex collapse mechanisms arising from material and geometric nonlinearities.</div></div>","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"305 ","pages":"Article 107558"},"PeriodicalIF":4.4,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-10-03DOI: 10.1016/j.compstruc.2024.107551
Ihtisham Khalid , Zahid Ahmed Qureshi , Haris Ali Khan , Selda Oterkus , Erkan Oterkus
The inverse finite element method (iFEM) emerged as a powerful tool in shape-sensing and structural health monitoring (SHM) applications with distinct advantages over existing methodologies. In this study, a quadrilateral inverse-plate element is formulated via a sub-parametric approach using bi-linear and non-conforming cubic Hermite basis functions for engineering structures, which can be modeled as thin plates. Numerical validation involves dense and assumed sparse sensor arrangements for in-plane, out-of-plane, and mixed general loading conditions. iFEM analysis reveals efficient monotonic convergence to analytical and high-fidelity finite element reference solutions. After successful numerical validation, defect detection analysis is performed considering minute geometric discontinuities and structural stiffness reduction because of latent subsurface defects under tensile and transverse loading conditions. The inverse formulation successfully resolves the presence of simulated defects under a sparse sensor arrangement. The proposed inverse-plate element is accurate in the full-field reconstruction of shape-sensing profiles and reliable in defect identification and quantification in thin plate structures.
{"title":"A quadrilateral inverse plate element for real-time shape-sensing and structural health monitoring of thin plate structures","authors":"Ihtisham Khalid , Zahid Ahmed Qureshi , Haris Ali Khan , Selda Oterkus , Erkan Oterkus","doi":"10.1016/j.compstruc.2024.107551","DOIUrl":"10.1016/j.compstruc.2024.107551","url":null,"abstract":"<div><div>The inverse finite element method (iFEM) emerged as a powerful tool in shape-sensing and structural health monitoring (SHM) applications with distinct advantages over existing methodologies. In this study, a quadrilateral inverse-plate element is formulated via a sub-parametric approach using bi-linear and non-conforming cubic Hermite basis functions for engineering structures, which can be modeled as thin plates. Numerical validation involves dense and assumed sparse sensor arrangements for in-plane, out-of-plane, and mixed general loading conditions. iFEM analysis reveals efficient monotonic convergence to analytical and high-fidelity finite element reference solutions. After successful numerical validation, defect detection analysis is performed considering minute geometric discontinuities and structural stiffness reduction because of latent subsurface defects under tensile and transverse loading conditions. The inverse formulation successfully resolves the presence of simulated defects under a sparse sensor arrangement. The proposed inverse-plate element is accurate in the full-field reconstruction of shape-sensing profiles and reliable in defect identification and quantification in thin plate structures.</div></div>","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"305 ","pages":"Article 107551"},"PeriodicalIF":4.4,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-10-03DOI: 10.1016/j.compstruc.2024.107543
Michael Neunteufel , Joachim Schöberl
In this paper we extend the recently introduced mixed Hellan–Herrmann–Johnson (HHJ) method for nonlinear Koiter shells to nonlinear Naghdi shells by means of a hierarchical approach. The additional shearing degrees of freedom are discretized by -conforming Nédélec finite elements entailing a shear locking free method. By linearizing the models we obtain in the small strain regime linear Kirchhoff–Love and Reissner–Mindlin shell formulations, which reduce for plates to the originally proposed HHJ and TDNNS methods for Kirchhoff–Love and Reissner–Mindlin plates, respectively. By interpolating the membrane strains into the so-called Regge finite element space we obtain locking-free arbitrary order shell methods. Additionally, the methods can be directly applied to structures with kinks and branched shells. Several numerical examples and experiments are performed validating the excellent performance of the proposed shell elements.
{"title":"The Hellan–Herrmann–Johnson and TDNNS methods for linear and nonlinear shells","authors":"Michael Neunteufel , Joachim Schöberl","doi":"10.1016/j.compstruc.2024.107543","DOIUrl":"10.1016/j.compstruc.2024.107543","url":null,"abstract":"<div><div>In this paper we extend the recently introduced mixed Hellan–Herrmann–Johnson (HHJ) method for nonlinear Koiter shells to nonlinear Naghdi shells by means of a hierarchical approach. The additional shearing degrees of freedom are discretized by <span><math><mi>H</mi><mo>(</mo><mrow><mi>curl</mi></mrow><mo>)</mo></math></span>-conforming Nédélec finite elements entailing a shear locking free method. By linearizing the models we obtain in the small strain regime linear Kirchhoff–Love and Reissner–Mindlin shell formulations, which reduce for plates to the originally proposed HHJ and TDNNS methods for Kirchhoff–Love and Reissner–Mindlin plates, respectively. By interpolating the membrane strains into the so-called Regge finite element space we obtain locking-free arbitrary order shell methods. Additionally, the methods can be directly applied to structures with kinks and branched shells. Several numerical examples and experiments are performed validating the excellent performance of the proposed shell elements.</div></div>","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"305 ","pages":"Article 107543"},"PeriodicalIF":4.4,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study introduces the vibration behavior of uniform functionally graded (FG) cylindrical shells by Jacobi-Ritz method. The first-order shear deformation theory (FSDT) and domain decomposition method (DDM) are used to establish the theoretical model. The complex constraint of FG cylindrical shells is realized by using artificial springs. The Jacobi orthogonal polynomials combined with Fourier series can be expanded to denote the admissible displacement field of the structure. Finally, the Rayleigh-Ritz method has been adopted to solve the behavior of free vibration and forced vibration. The transient vibration behavior of FG cylindrical shells is solved in accordance with Newmark-β integration method. For verify the validity of Jacobi-Ritz method, the convergence study is carried out, and the calculation results of FG cylindrical shells with various influencing factors such as boundary conditions, material parameters, excitation load forms and geometric dimensions are given, and the FEM results and published literature are compared. The computation show that the method has high precision and can supply theoretical basis for vibration control of FG cylindrical shell. This study introduces the vibration behavior of uniform functionally graded (FG) cylindrical shells by Jacobi-Ritz method. The first-order shear deformation theory (FSDT) and domain decomposition method (DDM) are used to establish the theoretical model. The complex constraint of FG cylindrical shells is realized by using artificial springs. The Jacobi orthogonal polynomials combined with Fourier series can be expanded to denote the admissible displacement field of the structure. Finally, the Rayleigh-Ritz method has been adopted to solve the behavior of free vibration and forced vibration. The transient vibration behavior of FG cylindrical shells is solved in accordance with Newmark-β integration method. For verify the validity of Jacobi-Ritz method, the convergence study is carried out, and the calculation results of FG cylindrical shells with various influencing factors such as boundary conditions, material parameters, excitation load forms and geometric dimensions are given, and the FEM results and published literature are compared. The computation show that the method has high precision and can supply theoretical basis for vibration control of FG cylindrical shell.
{"title":"Jacobi-Ritz method for dynamic analysis of functionally graded cylindrical shell with general boundary conditions based on FSDT","authors":"Jiawei Xu, Cong Gao, Haichao Li, Fuzhen Pang, Jiajun Zheng, Tianyi Hang","doi":"10.1016/j.compstruc.2024.107552","DOIUrl":"10.1016/j.compstruc.2024.107552","url":null,"abstract":"<div><div>This study introduces the vibration behavior of uniform functionally graded (FG) cylindrical shells by Jacobi-Ritz method. The first-order shear deformation theory (FSDT) and domain decomposition method (DDM) are used to establish the theoretical model. The complex constraint of FG cylindrical shells is realized by using artificial springs. The Jacobi orthogonal polynomials combined with Fourier series can be expanded to denote the admissible displacement field of the structure. Finally, the Rayleigh-Ritz method has been adopted to solve the behavior of free vibration and forced vibration. The transient vibration behavior of FG cylindrical shells is solved in accordance with Newmark-<em>β</em> integration method. For verify the validity of Jacobi-Ritz method, the convergence study is carried out, and the calculation results of FG cylindrical shells with various influencing factors such as boundary conditions, material parameters, excitation load forms and geometric dimensions are given, and the FEM results and published literature are compared. The computation show that the method has high precision and can supply theoretical basis for vibration control of FG cylindrical shell. <span><span>This study introduces the vibration behavior of uniform functionally graded (FG) cylindrical shells by Jacobi-Ritz method. The first-order shear deformation theory (FSDT) and domain decomposition method (DDM) are used to establish the theoretical model. The complex constraint of FG cylindrical shells is realized by using artificial springs. The Jacobi orthogonal polynomials combined with<!--> </span><svg><path></path></svg></span>Fourier series can be expanded to denote the admissible displacement field of the structure. Finally, the Rayleigh-Ritz method has been adopted to solve the behavior of free vibration and forced vibration. The transient vibration behavior of FG cylindrical shells is solved in accordance with Newmark-<em>β</em> <!-->integration method. For verify the validity of Jacobi-Ritz method, the convergence study is carried out, and the calculation results of FG cylindrical shells with various influencing factors such as boundary conditions, material parameters, excitation load forms and geometric dimensions are given, and the FEM results and published literature are compared. The computation show that the method has high precision and can supply theoretical basis for vibration control of FG cylindrical shell.</div></div>","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"305 ","pages":"Article 107552"},"PeriodicalIF":4.4,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-26DOI: 10.1016/j.compstruc.2024.107550
Zhao Zhang , Hao Yu , Hengan Wu , Qingpeng Chen
This paper presents a novel simultaneous shape and topology optimization approach of shell structures based on isogeometric analysis and density distribution field. In the optimization approach, Non-Uniform Rational B-Splines (NURBS) technology is utilized to describe the geometry and material distribution of the shell structures. The coordinates and densities of the NURBS control points are utilized as design variables to simultaneously optimize the shape and topology of shell structures. The proposed approach offers significant advantages, including ease of implementation, seamless integration with CAD models, high efficiency, and smooth, clear boundaries. Two representative examples are performed to demonstrate the effectiveness of the proposed approach. The optimized configurations are compared with other works and commercial software results.
{"title":"A simultaneous shape and topology optimization approach of shell structures based on isogeometric analysis and density distribution field","authors":"Zhao Zhang , Hao Yu , Hengan Wu , Qingpeng Chen","doi":"10.1016/j.compstruc.2024.107550","DOIUrl":"10.1016/j.compstruc.2024.107550","url":null,"abstract":"<div><div>This paper presents a novel simultaneous shape and topology optimization approach of shell structures based on isogeometric analysis and density distribution field. In the optimization approach, Non-Uniform Rational B-Splines (NURBS) technology is utilized to describe the geometry and material distribution of the shell structures. The coordinates and densities of the NURBS control points are utilized as design variables to simultaneously optimize the shape and topology of shell structures. The proposed approach offers significant advantages, including ease of implementation, seamless integration with CAD models, high efficiency, and smooth, clear boundaries. Two representative examples are performed to demonstrate the effectiveness of the proposed approach. The optimized configurations are compared with other works and commercial software results.</div></div>","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"305 ","pages":"Article 107550"},"PeriodicalIF":4.4,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-25DOI: 10.1016/j.compstruc.2024.107549
Karin L. Yu , Michael A. Kraus , Eleni Chatzi , Walter Kaufmann
Reinforced concrete structures featuring discontinuity regions are complex to design and often susceptible to errors linked to numerical analysis methods. For such structural design problems, strut-and-tie models offer a simple, intuitive and safe design method based on the lower bound theorem of plasticity. Although intuitive, the derivation of strut-and-tie models requires nonnegligible effort and a certain degree of expertise to navigate the highdimensional design space. The automated generation of strut-and-tie models is nontrivial with existing optimisation-based methods, which struggle with accounting for fabrication aspects or incorporating user adaptations.
This paper presents a novel grammar-based approach for generating practical strut-and-tie models by representing them as graphs and constructing a graph grammar. It consists of rules customised to consider engineering judgement, significantly reducing the dimensionality of the design space. The sequential application of such rules allows for human-computer interaction and aids engineers in decision-making, while being kept in the loop. Parsing four common design examples from the literature demonstrates the efficacy of this approach. The developed designs are more practical compared with existing optimisation-based suggestions. This interpretable grammar-based approach closely follows the intuitive decision-making process of practising structural engineers, which could be adapted to support further structural engineering design tasks.
{"title":"Grammar-based generation of strut-and-tie models for designing reinforced concrete structures","authors":"Karin L. Yu , Michael A. Kraus , Eleni Chatzi , Walter Kaufmann","doi":"10.1016/j.compstruc.2024.107549","DOIUrl":"10.1016/j.compstruc.2024.107549","url":null,"abstract":"<div><div>Reinforced concrete structures featuring discontinuity regions are complex to design and often susceptible to errors linked to numerical analysis methods. For such structural design problems, strut-and-tie models offer a simple, intuitive and safe design method based on the lower bound theorem of plasticity. Although intuitive, the derivation of strut-and-tie models requires nonnegligible effort and a certain degree of expertise to navigate the highdimensional design space. The automated generation of strut-and-tie models is nontrivial with existing optimisation-based methods, which struggle with accounting for fabrication aspects or incorporating user adaptations.</div><div>This paper presents a novel grammar-based approach for generating practical strut-and-tie models by representing them as graphs and constructing a graph grammar. It consists of rules customised to consider engineering judgement, significantly reducing the dimensionality of the design space. The sequential application of such rules allows for human-computer interaction and aids engineers in decision-making, while being kept in the loop. Parsing four common design examples from the literature demonstrates the efficacy of this approach. The developed designs are more practical compared with existing optimisation-based suggestions. This interpretable grammar-based approach closely follows the intuitive decision-making process of practising structural engineers, which could be adapted to support further structural engineering design tasks.</div></div>","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"305 ","pages":"Article 107549"},"PeriodicalIF":4.4,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-24DOI: 10.1016/j.compstruc.2024.107548
Dongdong Xie , Yonggang Zheng , Bo Wang , Shengli Xu , Yongfeng Sui , Qiang Gao
Considering the non-negligible multistage coupling effect of stages in multi-stage cyclic structure, such as bladed disk systems in aircraft turbo engines, a method is established for the static analysis of multistage cyclic structures. A special coordinate system is established based on the structural characteristics of the multistage cyclic structure. In this coordinate system, the sectors of a given disk have the same position; therefore, the stiffness matrices of any sector of the same disk are identical. Then, based on a two-stage Guyan reduction, the internal degrees of freedom (DOFs) of the disks are condensed and the number of DOFs corresponding to the full structure is reduced to that corresponding to the interdisk structures. Furthermore, group theory and the properties of the block circulant matrix are used to significantly reduce the computational cost of the two-stage Guyan reduction. Compared to the analysis of the full finite element model, the proposed method introduces no approximation. The main advantages of the proposed method are its high accuracy, high efficiency, and less demand on computational resources. Numerical examples demonstrate the accuracy and efficiency of the proposed method.
{"title":"A method for static analysis of multistage cyclic structure based on group theory and two-stage Guyan reduction","authors":"Dongdong Xie , Yonggang Zheng , Bo Wang , Shengli Xu , Yongfeng Sui , Qiang Gao","doi":"10.1016/j.compstruc.2024.107548","DOIUrl":"10.1016/j.compstruc.2024.107548","url":null,"abstract":"<div><div>Considering the non-negligible multistage coupling effect of stages in multi-stage cyclic structure, such as bladed disk systems in aircraft turbo engines, a method is established for the static analysis of multistage cyclic structures. A special coordinate system is established based on the structural characteristics of the multistage cyclic structure. In this coordinate system, the sectors of a given disk have the same position; therefore, the stiffness matrices of any sector of the same disk are identical. Then, based on a two-stage Guyan reduction, the internal degrees of freedom (DOFs) of the disks are condensed and the number of DOFs corresponding to the full structure is reduced to that corresponding to the interdisk structures. Furthermore, group theory and the properties of the block circulant matrix are used to significantly reduce the computational cost of the two-stage Guyan reduction. Compared to the analysis of the full finite element model, the proposed method introduces no approximation. The main advantages of the proposed method are its high accuracy, high efficiency, and less demand on computational resources. Numerical examples demonstrate the accuracy and efficiency of the proposed method.</div></div>","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"305 ","pages":"Article 107548"},"PeriodicalIF":4.4,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-23DOI: 10.1016/j.compstruc.2024.107519
J.A. Teixeira de Freitas , C. Tiago , E.M.B.R. Pereira
The polynomial boundary basis usually applied in the implementation of hybrid-Trefftz stress elements for plate bending is extended to render its rate of convergence insensitive to the shear-to-bending stiffness ratio of the plate. The boundary basis is also extended to improve the accuracy of the element in the modelling of boundary layer effects and of singular stress fields caused by wedge effects. Numerical testing problems are selected to illustrate and validate the effect of the proposed extensions on the stabilization and improvement of finite element solutions. The solutions modelling boundary layer effects in Mindlin-Reissner plates are used to recover the equivalent shear and corner force concepts of the Kirchhoff plate bending model.
{"title":"Stabilization and improvement of the convergence of hybrid-Trefftz stress elements for plate bending analysis","authors":"J.A. Teixeira de Freitas , C. Tiago , E.M.B.R. Pereira","doi":"10.1016/j.compstruc.2024.107519","DOIUrl":"10.1016/j.compstruc.2024.107519","url":null,"abstract":"<div><div>The polynomial boundary basis usually applied in the implementation of hybrid-Trefftz stress elements for plate bending is extended to render its rate of convergence insensitive to the shear-to-bending stiffness ratio of the plate. The boundary basis is also extended to improve the accuracy of the element in the modelling of boundary layer effects and of singular stress fields caused by wedge effects. Numerical testing problems are selected to illustrate and validate the effect of the proposed extensions on the stabilization and improvement of finite element solutions. The solutions modelling boundary layer effects in Mindlin-Reissner plates are used to recover the equivalent shear and corner force concepts of the Kirchhoff plate bending model.</div></div>","PeriodicalId":50626,"journal":{"name":"Computers & Structures","volume":"305 ","pages":"Article 107519"},"PeriodicalIF":4.4,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0045794924002487/pdfft?md5=1a34466f1902b9a08c3c30857fd81bc4&pid=1-s2.0-S0045794924002487-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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