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Finite particle method for progressive failure simulation of truss structures / Ying Yu in Journal of structural engineering, Vol. 137 N° 10 (Octobre 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 10 (Octobre 2011) . - pp. 1168-1181 Titre : Finite particle method for progressive failure simulation of truss structures Type de document : texte imprimé Auteurs : Ying Yu, Auteur ; Glaucio H. Paulino, Auteur ; Luo, Yaozhi, Auteur Année de publication : 2012 Article en page(s) : pp. 1168-1181 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Finite  particle  method  Vector  mechanics  Explicit  time  integration  Failure  model  Progressive  failure  Energy  conservation Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A structural analysis framework called the finite particle method (FPM) for structure failure simulation is presented in this paper. The traditional finite-element method is generated from continuum mechanics and the variational principle; vector mechanics form the basis of FPM. It discretizes the domain with finite particles whose motions are described by Newton’s second law. Instead of imposing a global equilibrium of the entire continuous system, FPM enforces equilibrium on each particle. Thus, particles are free to separate from one another, which is advantageous in the simulation of structural failure. One of the features of this approach is that no iterations to follow nonlinear laws are necessary, and no global matrices are formed or solved in this method. A convected material frame is used to evaluate the structure deformation and internal force. The explicit time integration is adopted to solve the equation of motion. To simulate the truss structure failure, a failure criterion on the basis of the ideal plastic constitutive model and a failure modeling algorithm are proposed by using FPM. According to the energy conservation study of a two-dimensional (2D) truss, the energy is decomposed and balanced during the failure process. Also, a more complicated three-dimensional (3D) structure failure simulation is given. The comparison of the simulation results and the practical failure mode shows the capability of this method. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i10/p1168_s1?isAuthorized=no [article] Finite particle method for progressive failure simulation of truss structures [texte imprimé] / Ying Yu, Auteur ; Glaucio H. Paulino, Auteur ; Luo, Yaozhi, Auteur . - 2012 . - pp. 1168-1181. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 10 (Octobre 2011) . - pp. 1168-1181 Mots-clés : Finite  particle  method  Vector  mechanics  Explicit  time  integration  Failure  model  Progressive  failure  Energy  conservation Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A structural analysis framework called the finite particle method (FPM) for structure failure simulation is presented in this paper. The traditional finite-element method is generated from continuum mechanics and the variational principle; vector mechanics form the basis of FPM. It discretizes the domain with finite particles whose motions are described by Newton’s second law. Instead of imposing a global equilibrium of the entire continuous system, FPM enforces equilibrium on each particle. Thus, particles are free to separate from one another, which is advantageous in the simulation of structural failure. One of the features of this approach is that no iterations to follow nonlinear laws are necessary, and no global matrices are formed or solved in this method. A convected material frame is used to evaluate the structure deformation and internal force. The explicit time integration is adopted to solve the equation of motion. To simulate the truss structure failure, a failure criterion on the basis of the ideal plastic constitutive model and a failure modeling algorithm are proposed by using FPM. According to the energy conservation study of a two-dimensional (2D) truss, the energy is decomposed and balanced during the failure process. Also, a more complicated three-dimensional (3D) structure failure simulation is given. The comparison of the simulation results and the practical failure mode shows the capability of this method. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i10/p1168_s1?isAuthorized=no

Force finding of tensegrity systems using simulated annealing algorithm / Xu, Xian in Journal of structural engineering, Vol. 136 N° 8 (Août 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 8 (Août 2010) . - pp. 1027-1031 Titre : Force finding of tensegrity systems using simulated annealing algorithm Type de document : texte imprimé Auteurs : Xu, Xian, Auteur ; Luo, Yaozhi, Auteur Année de publication : 2011 Article en page(s) : pp. 1027-1031 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Tensegrity  Prestress  optimization  Simulated  annealing  algorithm Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : In this paper, an optimization model for force finding of tensegrity systems with considerations of the geometrical stability condition, the unilateral property of members, and the evenness requirement of internal forces was developed. The simulated annealing algorithm was used to solve this optimization problem. Force finding of several typical tensegrity systems was carried out with the proposed method. It was found that the optimized solutions were very close to the analytical solutions and able to reflect the geometrical symmetry of the structures. It also verified that the proposed method is applicable to tensegrity systems under consideration including simple two-dimensional structures and complex three-dimensional multimodular structures. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i8/p1027_s1?isAuthorized=no [article] Force finding of tensegrity systems using simulated annealing algorithm [texte imprimé] / Xu, Xian, Auteur ; Luo, Yaozhi, Auteur . - 2011 . - pp. 1027-1031. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 8 (Août 2010) . - pp. 1027-1031 Mots-clés : Tensegrity  Prestress  optimization  Simulated  annealing  algorithm Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : In this paper, an optimization model for force finding of tensegrity systems with considerations of the geometrical stability condition, the unilateral property of members, and the evenness requirement of internal forces was developed. The simulated annealing algorithm was used to solve this optimization problem. Force finding of several typical tensegrity systems was carried out with the proposed method. It was found that the optimized solutions were very close to the analytical solutions and able to reflect the geometrical symmetry of the structures. It also verified that the proposed method is applicable to tensegrity systems under consideration including simple two-dimensional structures and complex three-dimensional multimodular structures. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i8/p1027_s1?isAuthorized=no

Multistable tensegrity structures / Xu, Xian in Journal of structural engineering, Vol. 137 N° 1 (Janvier 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 1 (Janvier 2011) . - pp. 117-123 Titre : Multistable tensegrity structures Type de document : texte imprimé Auteurs : Xu, Xian, Auteur ; Luo, Yaozhi, Auteur Année de publication : 2011 Article en page(s) : pp. 117-123 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Multistable  Tensegrity  structures  Form  finding  State  transformation Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Tensegrity structures have been intensively studied since they appeared in the 1950s. Their applications have been extended from architecture to other areas including aerospace structures, cell mechanics, and robotics. In this paper, an interesting characteristic, the so-called multistability, is reported. A detailed investigation on a multistable tensegrity structure whose basic stable configuration corresponds to the expanded octahedron tensegrity is presented. Using an evolutionary form-finding scheme, together with the dynamic relaxation method, two other self-equilibrated configurations with higher strain energies are found. The stabilities of these configurations are verified by a matrix analysis process. Then, an investigation on the actuations and the corresponding threshold energies triggering the transformations between the different configurations is carried out. A typical set of actuation loads and the corresponding threshold energies for the state transformations are identified. The existence and the stability of the multistable configurations are verified by physical models. This study provides a theoretical basis for the further applications of multistable tensegrity structures. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i1/p117_s1?isAuthorized=no [article] Multistable tensegrity structures [texte imprimé] / Xu, Xian, Auteur ; Luo, Yaozhi, Auteur . - 2011 . - pp. 117-123. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 1 (Janvier 2011) . - pp. 117-123 Mots-clés : Multistable  Tensegrity  structures  Form  finding  State  transformation Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Tensegrity structures have been intensively studied since they appeared in the 1950s. Their applications have been extended from architecture to other areas including aerospace structures, cell mechanics, and robotics. In this paper, an interesting characteristic, the so-called multistability, is reported. A detailed investigation on a multistable tensegrity structure whose basic stable configuration corresponds to the expanded octahedron tensegrity is presented. Using an evolutionary form-finding scheme, together with the dynamic relaxation method, two other self-equilibrated configurations with higher strain energies are found. The stabilities of these configurations are verified by a matrix analysis process. Then, an investigation on the actuations and the corresponding threshold energies triggering the transformations between the different configurations is carried out. A typical set of actuation loads and the corresponding threshold energies for the state transformations are identified. The existence and the stability of the multistable configurations are verified by physical models. This study provides a theoretical basis for the further applications of multistable tensegrity structures. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i1/p117_s1?isAuthorized=no

Tensegrity structures with buckling members explain nonlinear stiffening and reversible softening of actin networks / Xu, Xian in Journal of engineering mechanics, Vol. 135 N° 12 (Décembre 2009) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 135 N° 12 (Décembre 2009) . - pp. 1368-1374 Titre : Tensegrity structures with buckling members explain nonlinear stiffening and reversible softening of actin networks Type de document : texte imprimé Auteurs : Xu, Xian, Auteur ; Luo, Yaozhi, Auteur Article en page(s) : pp. 1368-1374 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Buckling  Postbuckling  stiffening  Softening  Stress  Structural  members Résumé : In this paper, a three-member tensegrity structure is used as a conceptual model for the dendritic actin network in living cells. The pre and postbuckling behavior of the tensegrity is analyzed basing on the energy method. Analytical simulations are carried out on the tensegrity by using the experimentally obtained scales and mechanic properties of actin-filaments for the structural members of the tensegrity. The model exhibits a stress stiffening regime followed by a stress softening regime in the load-stiffness relationship, which qualitatively tallies with the experimentally observed response of actin networks. Due to the simplicity of the model, there is only a single compressed member and the structure buckles abruptly, which results a softening regime much steeper than that observed in the actin network. To take the member length variety into account, we propose a conceptual large-scale tensegrity system with various member lengths, and its behavior is approximately estimated by the mean response of a large number of three-member tensegrity cells with their member length varying in the range of filament lengths. The obtained mean response exhibits a much better fitness to the response of actin networks than those exhibited by the single tensegrity model. The findings reported in this paper indicate that the dendritic actin network may work as a complex tensegrity system, when it is subjected to a stress. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JENMDT&smode=strres [...] [article] Tensegrity structures with buckling members explain nonlinear stiffening and reversible softening of actin networks [texte imprimé] / Xu, Xian, Auteur ; Luo, Yaozhi, Auteur . - pp. 1368-1374. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 135 N° 12 (Décembre 2009) . - pp. 1368-1374 Mots-clés : Buckling  Postbuckling  stiffening  Softening  Stress  Structural  members Résumé : In this paper, a three-member tensegrity structure is used as a conceptual model for the dendritic actin network in living cells. The pre and postbuckling behavior of the tensegrity is analyzed basing on the energy method. Analytical simulations are carried out on the tensegrity by using the experimentally obtained scales and mechanic properties of actin-filaments for the structural members of the tensegrity. The model exhibits a stress stiffening regime followed by a stress softening regime in the load-stiffness relationship, which qualitatively tallies with the experimentally observed response of actin networks. Due to the simplicity of the model, there is only a single compressed member and the structure buckles abruptly, which results a softening regime much steeper than that observed in the actin network. To take the member length variety into account, we propose a conceptual large-scale tensegrity system with various member lengths, and its behavior is approximately estimated by the mean response of a large number of three-member tensegrity cells with their member length varying in the range of filament lengths. The obtained mean response exhibits a much better fitness to the response of actin networks than those exhibited by the single tensegrity model. The findings reported in this paper indicate that the dendritic actin network may work as a complex tensegrity system, when it is subjected to a stress. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JENMDT&smode=strres [...]