The laminated beam with uniformly vertical displacement can be divided into contact region and separation region when bending deformation occurs. Friction between the interfaces will cause the stiffness inconsistency between the separation region and contact region. In this paper, calculation formula of section stiffness considering interface friction effect is derived. Assuming that the beam vibrates freely in equal wavelength and equal stiffness forms respectively, the calculating formulas of natural vibration frequencies of simply supported and cantilever beams are derived. Finally, based on a steel-concrete laminated test beam with uniform vertical displacement, the natural vibration frequencies of the beam are calculated. The conclusions are as follows: The derived formulas can calculate the natural vibration frequencies of laminated beams under different interface states effectively; The influence of friction effect on the vibration frequency of laminated beams becomes more and more obvious with the increase of the order.
{"title":"Theoretical Investigation on Stiffness and Vibration Characteristics of Laminated Beams with Uniformly Vertical Displacement","authors":"X. Liang, Bo Chen, Wenrui He","doi":"10.1590/1679-78257035","DOIUrl":"https://doi.org/10.1590/1679-78257035","url":null,"abstract":"The laminated beam with uniformly vertical displacement can be divided into contact region and separation region when bending deformation occurs. Friction between the interfaces will cause the stiffness inconsistency between the separation region and contact region. In this paper, calculation formula of section stiffness considering interface friction effect is derived. Assuming that the beam vibrates freely in equal wavelength and equal stiffness forms respectively, the calculating formulas of natural vibration frequencies of simply supported and cantilever beams are derived. Finally, based on a steel-concrete laminated test beam with uniform vertical displacement, the natural vibration frequencies of the beam are calculated. The conclusions are as follows: The derived formulas can calculate the natural vibration frequencies of laminated beams under different interface states effectively; The influence of friction effect on the vibration frequency of laminated beams becomes more and more obvious with the increase of the order.","PeriodicalId":18192,"journal":{"name":"Latin American Journal of Solids and Structures","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67620481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gelson de Sousa Alves, F. Evangelista Junior, Guilherme Oliveira Ferraz de Paiva
This paper proposes interface and polynomial enrichments using the generalized finite element method (IGFEM) for the material interface in composite materials without matching the finite element mesh to the boundaries of different materials. Applications in structural members such as laminated beams and heterogeneous composites (matrix and inclusions) employing coarse and fine meshes are employed. The results were compared with conventional GFEM and analytical solutions. Verification and simulations proved the efficiency of the suggested framework for solving problems with discontinuous gradients resulting from a material interface. The proposed method allows flexibility in mesh generation for composite materials by letting the interface be embedded in an element without the need to match the mesh to the material interface. This improves the computational efficiency over conventional methods.
{"title":"A generalized finite element interface method for mesh reduction of composite materials simulations","authors":"Gelson de Sousa Alves, F. Evangelista Junior, Guilherme Oliveira Ferraz de Paiva","doi":"10.1590/1679-78257273","DOIUrl":"https://doi.org/10.1590/1679-78257273","url":null,"abstract":"This paper proposes interface and polynomial enrichments using the generalized finite element method (IGFEM) for the material interface in composite materials without matching the finite element mesh to the boundaries of different materials. Applications in structural members such as laminated beams and heterogeneous composites (matrix and inclusions) employing coarse and fine meshes are employed. The results were compared with conventional GFEM and analytical solutions. Verification and simulations proved the efficiency of the suggested framework for solving problems with discontinuous gradients resulting from a material interface. The proposed method allows flexibility in mesh generation for composite materials by letting the interface be embedded in an element without the need to match the mesh to the material interface. This improves the computational efficiency over conventional methods.","PeriodicalId":18192,"journal":{"name":"Latin American Journal of Solids and Structures","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67621244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Intermediate diaphragms (ID) in bridges with precast girders are intended to improve load distribution among girders. Despite this, their efficacy has been doubted recently due to the complex construction tasks needed to join them to the girders. Accordingly, this work aimed to determine the effect of the number of IDs on the distribution of vertical loads and girders response of a simply supported bridge. Four bridge layouts (0, 1, 2, and 3 IDs) were analyzed using 3D computational grillage models. The load distribution factors from the models were compared to those calculated using the Engesser-Courbon and Fauchart methods to determine the latter’s accuracy in capturing the effect of the number of IDs. Moreover, the girders responses under the live loads in the current Colombian and Brazilian bridge design codes were assessed. The results show that the IDs have a more significant effect on the load distribution and deflection of interior girders than the exterior girders. Additionally, increasing the number of IDs reduced the maximum shear and torque while the bending moment and deflections remained nearly constant.
{"title":"Theoretical and computational simulation of the effect of the number of intermediate diaphragms on the live load distribution factors and structural response of a precast girder bridge","authors":"José Miguel Parra Benítez, J. Benjumea, V. Haach","doi":"10.1590/1679-78257120","DOIUrl":"https://doi.org/10.1590/1679-78257120","url":null,"abstract":"Intermediate diaphragms (ID) in bridges with precast girders are intended to improve load distribution among girders. Despite this, their efficacy has been doubted recently due to the complex construction tasks needed to join them to the girders. Accordingly, this work aimed to determine the effect of the number of IDs on the distribution of vertical loads and girders response of a simply supported bridge. Four bridge layouts (0, 1, 2, and 3 IDs) were analyzed using 3D computational grillage models. The load distribution factors from the models were compared to those calculated using the Engesser-Courbon and Fauchart methods to determine the latter’s accuracy in capturing the effect of the number of IDs. Moreover, the girders responses under the live loads in the current Colombian and Brazilian bridge design codes were assessed. The results show that the IDs have a more significant effect on the load distribution and deflection of interior girders than the exterior girders. Additionally, increasing the number of IDs reduced the maximum shear and torque while the bending moment and deflections remained nearly constant.","PeriodicalId":18192,"journal":{"name":"Latin American Journal of Solids and Structures","volume":"26 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67620342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nurfarhana Diyana Hadi, N. Hamid, Ili Farhana Azmi, R. Hassan, Y. Sutopo, B. Chao, Nurul Azmi Zainuddin
Two full-scale corner beam-column joints with and without fuse bars were designed, constructed, tested, analyzed and modeled under in-plane lateral cyclic loading presented herein. The first specimen was designed using Eurocode 8 and equipped with four fuse bars. Second specimen was designed using BS8110 (non-seismic code of practice) with corbel. All the specimens have similar size of foundation beams, columns and beams. Visual observation during testing showed that specimen with fuse bars suffered less damage as compare with specimen without fuse bars. Furthermore, specimen with fuse bars has higher lateral strength capacity, stiffness, ductility and equivalent viscous damping than specimen without fuse bars. Finally, there is good agreement of lateral strength capacity, ductility, stiffness and equivalent viscous damping which lies between 2% and 20% between experiment and modeling hysteresis loops. Thus, it is recommended that fuse bar as a green structural material can be installed inside the corner beam-column joint for RC buildings to cater strong earthquakes in high seismic regions.
{"title":"Comparison of Seismic Response Corner Beam-Column Joint with and without Fuse Bars Under In-Plane Lateral Cyclic Loading","authors":"Nurfarhana Diyana Hadi, N. Hamid, Ili Farhana Azmi, R. Hassan, Y. Sutopo, B. Chao, Nurul Azmi Zainuddin","doi":"10.1590/1679-78256581","DOIUrl":"https://doi.org/10.1590/1679-78256581","url":null,"abstract":"Two full-scale corner beam-column joints with and without fuse bars were designed, constructed, tested, analyzed and modeled under in-plane lateral cyclic loading presented herein. The first specimen was designed using Eurocode 8 and equipped with four fuse bars. Second specimen was designed using BS8110 (non-seismic code of practice) with corbel. All the specimens have similar size of foundation beams, columns and beams. Visual observation during testing showed that specimen with fuse bars suffered less damage as compare with specimen without fuse bars. Furthermore, specimen with fuse bars has higher lateral strength capacity, stiffness, ductility and equivalent viscous damping than specimen without fuse bars. Finally, there is good agreement of lateral strength capacity, ductility, stiffness and equivalent viscous damping which lies between 2% and 20% between experiment and modeling hysteresis loops. Thus, it is recommended that fuse bar as a green structural material can be installed inside the corner beam-column joint for RC buildings to cater strong earthquakes in high seismic regions.","PeriodicalId":18192,"journal":{"name":"Latin American Journal of Solids and Structures","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67618408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Juliano dos Santos Becho, M. Greco, Daniel Nelson Maciel
The development of a numerical formulation is presented to describe viscoelastic behavior considering shear effects. The nonlinear positional formulation of the Finite Element Method is used considering plane frame elements with Reissner kinematics. The description of the viscoelastic behavior is considered through the adoption of a stress-strain relation based on Boltzmann rheological model. The used kinematics allows to describe the decoupling between the rotations and the displacements in element cross-sections. This approach allows to evaluate the contribution of shear effects in viscoelastic behavior in an original way. Based on the developments and the results obtained, it is possible to observe that strains and displacements due to viscoelastic behavior are significantly superior to the results obtained considering Bernoulli-Euler kinematics hypothesis. It is possible to notice a better agreement between the obtained numerical results and the results in the literature. Results obtained from the developed formulation allow the assessment of the shear effects on the viscoelastic behavior of plane frames.
{"title":"Shear contribution on viscoelastic behavior of beams modeled using plane frame elements with Reissner kinematics","authors":"Juliano dos Santos Becho, M. Greco, Daniel Nelson Maciel","doi":"10.1590/1679-78256709","DOIUrl":"https://doi.org/10.1590/1679-78256709","url":null,"abstract":"The development of a numerical formulation is presented to describe viscoelastic behavior considering shear effects. The nonlinear positional formulation of the Finite Element Method is used considering plane frame elements with Reissner kinematics. The description of the viscoelastic behavior is considered through the adoption of a stress-strain relation based on Boltzmann rheological model. The used kinematics allows to describe the decoupling between the rotations and the displacements in element cross-sections. This approach allows to evaluate the contribution of shear effects in viscoelastic behavior in an original way. Based on the developments and the results obtained, it is possible to observe that strains and displacements due to viscoelastic behavior are significantly superior to the results obtained considering Bernoulli-Euler kinematics hypothesis. It is possible to notice a better agreement between the obtained numerical results and the results in the literature. Results obtained from the developed formulation allow the assessment of the shear effects on the viscoelastic behavior of plane frames.","PeriodicalId":18192,"journal":{"name":"Latin American Journal of Solids and Structures","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67619113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The suspension system has the role of regulating and extinguishing oscillations in the vehicle. To improve stability and comfort, the active suspension system is proposed to replace the passive suspension system. There are many algorithms used for active suspension system control, such as PID, LQR, Fuzzy, etc. Among them, the nonlinear control method which uses the SMC algorithm gives a stable performance. This research proposes the use of the SMC algorithm to control the operation of the active suspension system equipped with a quarter dynamics model. The process of linearization of the hydraulic actuator is presented in the paper. As a result of the simulation, the values of displacement and acceleration of the sprung mass were significantly reduced when the vehicle used the active suspension system controlled by the SMC algorithm. The SMC controller established in this paper provides stability in many situations. Therefore, the vehicle's smoothness and comfort have been significantly improved. In the future, intelligent algorithms can be combined with SMC algorithms to improve the efficiency of the controller.
{"title":"A Novel Sliding Mode Control Algorithm for an Active Suspension System Considering with the Hydraulic Actuator","authors":"Duc Ngoc Nguyen, T. Nguyen, N. Dang","doi":"10.1590/1679-78256883","DOIUrl":"https://doi.org/10.1590/1679-78256883","url":null,"abstract":"The suspension system has the role of regulating and extinguishing oscillations in the vehicle. To improve stability and comfort, the active suspension system is proposed to replace the passive suspension system. There are many algorithms used for active suspension system control, such as PID, LQR, Fuzzy, etc. Among them, the nonlinear control method which uses the SMC algorithm gives a stable performance. This research proposes the use of the SMC algorithm to control the operation of the active suspension system equipped with a quarter dynamics model. The process of linearization of the hydraulic actuator is presented in the paper. As a result of the simulation, the values of displacement and acceleration of the sprung mass were significantly reduced when the vehicle used the active suspension system controlled by the SMC algorithm. The SMC controller established in this paper provides stability in many situations. Therefore, the vehicle's smoothness and comfort have been significantly improved. In the future, intelligent algorithms can be combined with SMC algorithms to improve the efficiency of the controller.","PeriodicalId":18192,"journal":{"name":"Latin American Journal of Solids and Structures","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67619375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Impact of the Cracks on the Harmonic Response of Stiffened Steel Plates","authors":"Oguzhan Das, Can Gonenli","doi":"10.1590/1679-78256790","DOIUrl":"https://doi.org/10.1590/1679-78256790","url":null,"abstract":"","PeriodicalId":18192,"journal":{"name":"Latin American Journal of Solids and Structures","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67619400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The propagation of longitudinal and shear elastic waves through a multi-phase material was studied and the effective elastic properties of the medium were evaluated. The distribution of the reinforcing inclusions was considered random throughout the matrix. The effective dynamic properties of the composites, including their effective bulk and shear moduli and effective densities, were examined along with the effective phase velocity and attenuation of the incident P and S waves. The Sabina – Willis model was employed to study the wave propagation behavior, and the model performance was analyzed through comparison with experimental data from the literature. The results indicated that wave propagation significantly depended on the physical and mechanical properties of inclusions relative to those of the matrix and the normalized wave number of the propagated elastic wave. Moreover, despite the fact that the elastic properties of the incidence in the P and S waves exhibited a similar trend, their values differed significantly. The results can serve as a design criterion for composite materials under dynamic loading.
{"title":"Analysis of the Effective Dynamic Properties of Particulate Composites with Respect to Constituent Properties","authors":"Mohammad Rahimzadeh","doi":"10.1590/1679-78256893","DOIUrl":"https://doi.org/10.1590/1679-78256893","url":null,"abstract":"The propagation of longitudinal and shear elastic waves through a multi-phase material was studied and the effective elastic properties of the medium were evaluated. The distribution of the reinforcing inclusions was considered random throughout the matrix. The effective dynamic properties of the composites, including their effective bulk and shear moduli and effective densities, were examined along with the effective phase velocity and attenuation of the incident P and S waves. The Sabina – Willis model was employed to study the wave propagation behavior, and the model performance was analyzed through comparison with experimental data from the literature. The results indicated that wave propagation significantly depended on the physical and mechanical properties of inclusions relative to those of the matrix and the normalized wave number of the propagated elastic wave. Moreover, despite the fact that the elastic properties of the incidence in the P and S waves exhibited a similar trend, their values differed significantly. The results can serve as a design criterion for composite materials under dynamic loading.","PeriodicalId":18192,"journal":{"name":"Latin American Journal of Solids and Structures","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67619576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Structural elements can be damaged or defective due to man-made and natural disasters, which will result in structural resistance below the design value. Component replacement can effectively improve the safety of the structure and does not affect its later use. However, this construction process must dismantle defective components. If the process is not properly operated, it will cause progressive collapse of the structure. There are few studies on progressive collapse resistance based on field tests. In this paper, the alternate load path method is used to study the deformation mechanism of reinforced concrete shear wall structures when partial members fail. The maximum vertical displacement and strain of the beam end near the failure walls are obtained, and load transfer laws are analyzed. Based on the component replacement construction of a high-rise shear wall structure, the progressive collapse resistance mechanism of the shear wall structure is verified, which provides theoretical guidance for component replacement construction.
{"title":"Collapse Resistance Model and Deformation Mechanism of Shear Wall Replacement","authors":"Lei Qi, Xuansheng Cheng, Shanglong Zhang","doi":"10.1590/1679-78257189","DOIUrl":"https://doi.org/10.1590/1679-78257189","url":null,"abstract":"Structural elements can be damaged or defective due to man-made and natural disasters, which will result in structural resistance below the design value. Component replacement can effectively improve the safety of the structure and does not affect its later use. However, this construction process must dismantle defective components. If the process is not properly operated, it will cause progressive collapse of the structure. There are few studies on progressive collapse resistance based on field tests. In this paper, the alternate load path method is used to study the deformation mechanism of reinforced concrete shear wall structures when partial members fail. The maximum vertical displacement and strain of the beam end near the failure walls are obtained, and load transfer laws are analyzed. Based on the component replacement construction of a high-rise shear wall structure, the progressive collapse resistance mechanism of the shear wall structure is verified, which provides theoretical guidance for component replacement construction.","PeriodicalId":18192,"journal":{"name":"Latin American Journal of Solids and Structures","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67620841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Numerical form-finding is an effective method for determining the equilibrium configurations of tensegrity structures. However, the connectivity matrix is required to be input as initial data in most form-finding methods, and it is time-consuming and inconvenient for the designer in processing a complex structure with a large number of components. To address this issue, a novel automatic method of generating a connectivity matrix is proposed for three dimensional N-4 type tensegrity structures in this paper. The novelty of our algorithm is that the number of nodes is the only required parameter for the proposed method. Numerical examples are employed to validate our method. The results show that the proposed method is competent inform-finding for three-dimensional N-4 type tensegrity structures in terms of accuracy, efficiency and convergence.
{"title":"Automatic Form-finding of N-4 Type Tensegrity Structures","authors":"Xiaoming Yu, Yinghua Yang, Ya-dong Ji","doi":"10.1590/1679-78256735","DOIUrl":"https://doi.org/10.1590/1679-78256735","url":null,"abstract":"Numerical form-finding is an effective method for determining the equilibrium configurations of tensegrity structures. However, the connectivity matrix is required to be input as initial data in most form-finding methods, and it is time-consuming and inconvenient for the designer in processing a complex structure with a large number of components. To address this issue, a novel automatic method of generating a connectivity matrix is proposed for three dimensional N-4 type tensegrity structures in this paper. The novelty of our algorithm is that the number of nodes is the only required parameter for the proposed method. Numerical examples are employed to validate our method. The results show that the proposed method is competent inform-finding for three-dimensional N-4 type tensegrity structures in terms of accuracy, efficiency and convergence.","PeriodicalId":18192,"journal":{"name":"Latin American Journal of Solids and Structures","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67618746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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