Pub Date : 2022-12-30DOI: 10.15625/0866-7136/17943
Ngọc Trình Trần, Tu Luc Trinh, Tien Dao Ngoc, Tan Giap Van, Khuyen Truong Manh, Thuy Ha Dinh, M. Staat
Direct methods, comprising limit and shakedown analysis, are a branch of computational mechanics. They play a significant role in mechanical and civil engineering design. The concept of direct methods aims to determine the ultimate load carrying capacity of structures beyond the elastic range. In practical problems, the direct methods lead to nonlinear convex optimization problems with a large number of variables and constraints. If strength and loading are random quantities, the shakedown analysis can be formulated as stochastic programming problem. In this paper, a method called chance constrained programming is presented, which is an effective method of stochastic programming to solve shakedown analysis problems under random conditions of strength. In this study, the loading is deterministic, and the strength is a normally or lognormally distributed variable.
{"title":"FEM shakedown analysis of structures under random strength with chance constrained programming","authors":"Ngọc Trình Trần, Tu Luc Trinh, Tien Dao Ngoc, Tan Giap Van, Khuyen Truong Manh, Thuy Ha Dinh, M. Staat","doi":"10.15625/0866-7136/17943","DOIUrl":"https://doi.org/10.15625/0866-7136/17943","url":null,"abstract":"Direct methods, comprising limit and shakedown analysis, are a branch of computational mechanics. They play a significant role in mechanical and civil engineering design. The concept of direct methods aims to determine the ultimate load carrying capacity of structures beyond the elastic range. In practical problems, the direct methods lead to nonlinear convex optimization problems with a large number of variables and constraints. If strength and loading are random quantities, the shakedown analysis can be formulated as stochastic programming problem. In this paper, a method called chance constrained programming is presented, which is an effective method of stochastic programming to solve shakedown analysis problems under random conditions of strength. In this study, the loading is deterministic, and the strength is a normally or lognormally distributed variable.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115117195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-30DOI: 10.15625/0866-7136/17911
Thi Thu Hoai Bui, Thi Thom Tran, D. Nguyen
In this work, geometrically nonlinear behavior of sandwich composite beams reinforced by carbon nanotubes is studied, taking into account the influence of agglomeration of the carbon nanotubes (CNTs). The core of the sandwich beams is homogeneous while the two face sheets are made of CNT reinforced composite with the effective material properties being estimated by the Eshelby-Mori-Tanaka approach. A first-order shear deformable nonlinear beam element is formulated in the context of the total Lagrange formulation and used to construct the discretized nonlinear equilibrium equation. The Newton-Raphson based iterative procedure is used in conjunction with the arc-length method to trace the equilibrium paths of the beams. Detail parametric studies are carried out to illustrate the influence of the CNTs agglomeration, the amount of CNT volume fraction as well as the thicknesses of face sheets on the nonlinear behavior of the structure.
{"title":"Geometrically nonlinear analysis of sandwich composite beams reinforced by agglomeration carbon nanotubes","authors":"Thi Thu Hoai Bui, Thi Thom Tran, D. Nguyen","doi":"10.15625/0866-7136/17911","DOIUrl":"https://doi.org/10.15625/0866-7136/17911","url":null,"abstract":"In this work, geometrically nonlinear behavior of sandwich composite beams reinforced by carbon nanotubes is studied, taking into account the influence of agglomeration of the carbon nanotubes (CNTs). The core of the sandwich beams is homogeneous while the two face sheets are made of CNT reinforced composite with the effective material properties being estimated by the Eshelby-Mori-Tanaka approach. A first-order shear deformable nonlinear beam element is formulated in the context of the total Lagrange formulation and used to construct the discretized nonlinear equilibrium equation. The Newton-Raphson based iterative procedure is used in conjunction with the arc-length method to trace the equilibrium paths of the beams. Detail parametric studies are carried out to illustrate the influence of the CNTs agglomeration, the amount of CNT volume fraction as well as the thicknesses of face sheets on the nonlinear behavior of the structure.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126256989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-30DOI: 10.15625/0866-7136/17908
M. Cao, X. Nguyen
This paper proposed an analytical model to predict the confined concrete compressive strength with textile reinforced mortar (TRM). Based on 341 compression tests, different parameters have been analyzed to clarify their influence on the compressive strength of concrete column confined with TRM. The various existing models for compressed concrete columns confined by TRM have been assessed. Then, a simplified model for concrete elements wrapped with TRM are developed and verified through a best-fit analysis of the experimental database. It found that the proposed model showed good agreement with experimental results.
{"title":"Analytical model for the compressive strength of confined concrete with textile reinforced mortar","authors":"M. Cao, X. Nguyen","doi":"10.15625/0866-7136/17908","DOIUrl":"https://doi.org/10.15625/0866-7136/17908","url":null,"abstract":"This paper proposed an analytical model to predict the confined concrete compressive strength with textile reinforced mortar (TRM). Based on 341 compression tests, different parameters have been analyzed to clarify their influence on the compressive strength of concrete column confined with TRM. The various existing models for compressed concrete columns confined by TRM have been assessed. Then, a simplified model for concrete elements wrapped with TRM are developed and verified through a best-fit analysis of the experimental database. It found that the proposed model showed good agreement with experimental results.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127567986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-30DOI: 10.15625/0866-7136/17986
N. T. Khiem
This paper presents a unified approach to vibration analysis of functionally graded beams with transverse open-edge cracks based on the so-called vibration shape obtained as a general solution of vibration equations in the frequency domain. The crack is modeled by a pair of translational and rotational springs of stiffness computed from the crack depth in dependence upon functionally graded material parameters. The frequency-dependent vibration shape functions allow one not only to obtain the closed-form solution of both free and forced vibrations for multiple cracked FGM beams but also to develop the well-known methods such as Transfer Matrix Method or Dynamic Stiffness Method for analysis of FGM framed structures. The proposed theoretical developments have been illustrated by their application for modal analysis and frequency response analysis of multi-span and multistep beams.
{"title":"Vibrations of cracked functionally graded beams: General solution and application – A review","authors":"N. T. Khiem","doi":"10.15625/0866-7136/17986","DOIUrl":"https://doi.org/10.15625/0866-7136/17986","url":null,"abstract":"This paper presents a unified approach to vibration analysis of functionally graded beams with transverse open-edge cracks based on the so-called vibration shape obtained as a general solution of vibration equations in the frequency domain. The crack is modeled by a pair of translational and rotational springs of stiffness computed from the crack depth in dependence upon functionally graded material parameters. The frequency-dependent vibration shape functions allow one not only to obtain the closed-form solution of both free and forced vibrations for multiple cracked FGM beams but also to develop the well-known methods such as Transfer Matrix Method or Dynamic Stiffness Method for analysis of FGM framed structures. The proposed theoretical developments have been illustrated by their application for modal analysis and frequency response analysis of multi-span and multistep beams.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"195 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131543024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-30DOI: 10.15625/0866-7136/17944
N. Hoang, B. Boudon, Hyunki Bae, T. Dang, C. Bouzgarrou
This paper presents the approach of building a mathematical model for a parallel robotic manipulator with flexible links and elastic joints. The links to the base are assumed to be rigid bodies, and the thin connecting rods are assumed to be flexible links. The elasticity of the transmission from the actuators to the transmission is modeled by a torsional spring and viscous damper. This is a mixed system of rigid bodies, spring, and flexible links. The deformation motion of the elastic link is approximated by shape functions similar to the finite element method. The differential equations of motion are established by combining the substructure method and the Lagrange equation of the 2nd kind for the serial multibody system. Based on the differential equation established for the parallel robot manipulator of five bars, numerical simulations were carried out to investigate the response of the system.
{"title":"Modeling of parallel manipulators with flexible links and joints driven by electric actuators","authors":"N. Hoang, B. Boudon, Hyunki Bae, T. Dang, C. Bouzgarrou","doi":"10.15625/0866-7136/17944","DOIUrl":"https://doi.org/10.15625/0866-7136/17944","url":null,"abstract":"This paper presents the approach of building a mathematical model for a parallel robotic manipulator with flexible links and elastic joints. The links to the base are assumed to be rigid bodies, and the thin connecting rods are assumed to be flexible links. The elasticity of the transmission from the actuators to the transmission is modeled by a torsional spring and viscous damper. This is a mixed system of rigid bodies, spring, and flexible links. The deformation motion of the elastic link is approximated by shape functions similar to the finite element method. The differential equations of motion are established by combining the substructure method and the Lagrange equation of the 2nd kind for the serial multibody system. Based on the differential equation established for the parallel robot manipulator of five bars, numerical simulations were carried out to investigate the response of the system.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115391224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-30DOI: 10.15625/0866-7136/17933
Tran Quang Minh, V. M. Duc, D. Dong, V. H. Nam
The nonlinear buckling analysis of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) plates subjected to axial compression load is analytically examined in this paper. Assuming that the FG-CNTRC plates are stiffened by an oblique FG-CNTRC stiffener system. Reddy’s higher-order shear deformation plate theory (HSDPT) with the geometrical nonlinearities of von Kármán is applied to establish the basic formulations. Moreover, the smeared stiffener technique is successfully improved for the higher-order shear deformable anisotropic oblique stiffener system by using a homogeneous model of the anisotropic beam. Galerkin’s method is used to achieve the expressions of critical buckling loads and postbuckling load-deflection curves in explicit form. The numerical values display the influences of FG-CNTRC stiffeners, material, and geometrical properties on the nonlinear buckling response of plates.
{"title":"Nonlinear buckling analysis of higher-order shear deformable FG-CNTRC plates stiffened by oblique FG-CNTRC stiffeners","authors":"Tran Quang Minh, V. M. Duc, D. Dong, V. H. Nam","doi":"10.15625/0866-7136/17933","DOIUrl":"https://doi.org/10.15625/0866-7136/17933","url":null,"abstract":"The nonlinear buckling analysis of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) plates subjected to axial compression load is analytically examined in this paper. Assuming that the FG-CNTRC plates are stiffened by an oblique FG-CNTRC stiffener system. Reddy’s higher-order shear deformation plate theory (HSDPT) with the geometrical nonlinearities of von Kármán is applied to establish the basic formulations. Moreover, the smeared stiffener technique is successfully improved for the higher-order shear deformable anisotropic oblique stiffener system by using a homogeneous model of the anisotropic beam. Galerkin’s method is used to achieve the expressions of critical buckling loads and postbuckling load-deflection curves in explicit form. The numerical values display the influences of FG-CNTRC stiffeners, material, and geometrical properties on the nonlinear buckling response of plates.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120963903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-30DOI: 10.15625/0866-7136/17912
Tran Quang Hung, T. M. Tu, D. M. Duc
This report presents an analytical approach to the natural frequency analysis of a porous beam consisting of a host porous layer reinforced with graphene platelets (GPLs), namely GPL-reinforced porous core, and two piezoelectric outer layers. In the modelling, symmetric distributions of both porosity and GPLs in the core are supposed. The effective mechanical properties of the GPL-reinforced porous core are estimated by Halpin–Tsai model and the rule of mixture. The electric potential in each piezoelectric layer is assumed to vary linearly across its thickness. Two types of electrical boundary conditions, which are open- and closed-circuits, are considered for the free surfaces of the piezoelectric layers. Parabolic shear deformation beam theory associated with Hamilton’s principle is adopted to derive the governing equations of the free vibration. Afterwards these equations are solved analytically by Navier’s solution. Comparative and comprehensive studies are carried out to examine the accuracy and effects of parameters and conditions, such as GPL weight fraction, porosity coefficient, and electrical boundary conditions on the natural frequencies of the beam.
{"title":"Analytical solution for free vibration analysis of GPL-RP beam integrated with piezoelectric layers","authors":"Tran Quang Hung, T. M. Tu, D. M. Duc","doi":"10.15625/0866-7136/17912","DOIUrl":"https://doi.org/10.15625/0866-7136/17912","url":null,"abstract":"This report presents an analytical approach to the natural frequency analysis of a porous beam consisting of a host porous layer reinforced with graphene platelets (GPLs), namely GPL-reinforced porous core, and two piezoelectric outer layers. In the modelling, symmetric distributions of both porosity and GPLs in the core are supposed. The effective mechanical properties of the GPL-reinforced porous core are estimated by Halpin–Tsai model and the rule of mixture. The electric potential in each piezoelectric layer is assumed to vary linearly across its thickness. Two types of electrical boundary conditions, which are open- and closed-circuits, are considered for the free surfaces of the piezoelectric layers. Parabolic shear deformation beam theory associated with Hamilton’s principle is adopted to derive the governing equations of the free vibration. Afterwards these equations are solved analytically by Navier’s solution. Comparative and comprehensive studies are carried out to examine the accuracy and effects of parameters and conditions, such as GPL weight fraction, porosity coefficient, and electrical boundary conditions on the natural frequencies of the beam.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127498740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-30DOI: 10.15625/0866-7136/17948
N. N. Linh, V. A. Tuan, N. Tuan, N. D. Anh
Dynamic vibration absorber (DVA) integrated with a piezoelectric stack energy harvesting subjected to base excitation is introduced in this paper. The system of dynamic vibration absorber and piezoelectric stack energy harvesting system (DVA-PSEH) has two functions, the first is to reduce vibrations for the primary system, and the second is to convert a part of the vibrational energy into electricity through the piezoelectric effect. The mechanical and electrical responses of the electromechanical system are determined by the complex amplitude method, then the numerical simulations are carried out to investigate the characteristics of DVA-PSEH.
{"title":"Response analysis of undamped primary system subjected to base excitation with a dynamic vibration absorber integrated with a piezoelectric stack energy harvester","authors":"N. N. Linh, V. A. Tuan, N. Tuan, N. D. Anh","doi":"10.15625/0866-7136/17948","DOIUrl":"https://doi.org/10.15625/0866-7136/17948","url":null,"abstract":"Dynamic vibration absorber (DVA) integrated with a piezoelectric stack energy harvesting subjected to base excitation is introduced in this paper. The system of dynamic vibration absorber and piezoelectric stack energy harvesting system (DVA-PSEH) has two functions, the first is to reduce vibrations for the primary system, and the second is to convert a part of the vibrational energy into electricity through the piezoelectric effect. The mechanical and electrical responses of the electromechanical system are determined by the complex amplitude method, then the numerical simulations are carried out to investigate the characteristics of DVA-PSEH.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129458038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-30DOI: 10.15625/0866-7136/17588
N. Khang
Nguyen Van Dao is a leading expert in the field of mechanics in Vietnam. In this paper, we present some contributions of Nguyen Van Dao to the theory of nonlinear oscillation. His outstanding studies are the interaction between self-excited, forced and parametric vibrations, and equally important there is the effect of dynamic absorbers in nonlinear systems.
{"title":"The contributions of Professor Nguyen Van Dao in the Field of Nonlinear Oscillations","authors":"N. Khang","doi":"10.15625/0866-7136/17588","DOIUrl":"https://doi.org/10.15625/0866-7136/17588","url":null,"abstract":"Nguyen Van Dao is a leading expert in the field of mechanics in Vietnam. In this paper, we present some contributions of Nguyen Van Dao to the theory of nonlinear oscillation. His outstanding studies are the interaction between self-excited, forced and parametric vibrations, and equally important there is the effect of dynamic absorbers in nonlinear systems.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132995947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-30DOI: 10.15625/0866-7136/17917
P. N. Thanh, T. I. Thinh, Ta Thi Hien
In this investigation, by an analytical approach, the influence of several key parameters, especially the temperature on the sound isolation capacity of the symmetrically finite orthotropic laminated composite plate is studied. The plate is modeled with classic thin-plate theory and is assumed to be simply supported on all four sides. The incident acoustic pressure is modeled as a harmonic plane wave impinging on the plate at an arbitrary angle. The sound transmission loss is calculated from the ratio of incident to transmitted acoustic powers
{"title":"Effect of temperature on sound transmission loss of laminated composite plate","authors":"P. N. Thanh, T. I. Thinh, Ta Thi Hien","doi":"10.15625/0866-7136/17917","DOIUrl":"https://doi.org/10.15625/0866-7136/17917","url":null,"abstract":"In this investigation, by an analytical approach, the influence of several key parameters, especially the temperature on the sound isolation capacity of the symmetrically finite orthotropic laminated composite plate is studied. The plate is modeled with classic thin-plate theory and is assumed to be simply supported on all four sides. The incident acoustic pressure is modeled as a harmonic plane wave impinging on the plate at an arbitrary angle. The sound transmission loss is calculated from the ratio of incident to transmitted acoustic powers","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130912359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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