We use variational method to examine buckling of chiral elastic rings spanned by fluid films. We find that the critical surface tension of the fluid film at which buckling occurs depends on the degree of chirality, regardless whether the ring possesses left-handed chirality or right-handed chirality. Additionally, the chirality always has a destabilizing effect on buckling, yielding to buckle at a critical surface tension smaller than that of the achiral elastic rings. The destabilizing effect of chirality, however, can be reduced by increasing the twisting rigidity to bending rigidity of filaments (twist-to-bend ratio).
{"title":"Buckling of chiral elastic rings spanned by fluid films","authors":"Hoang Minh Tuan, Nguyen Thi Linh Lan, Tran Minh Tuyen","doi":"10.15625/0866-7136/16726","DOIUrl":"https://doi.org/10.15625/0866-7136/16726","url":null,"abstract":"We use variational method to examine buckling of chiral elastic rings spanned by fluid films. We find that the critical surface tension of the fluid film at which buckling occurs depends on the degree of chirality, regardless whether the ring possesses left-handed chirality or right-handed chirality. Additionally, the chirality always has a destabilizing effect on buckling, yielding to buckle at a critical surface tension smaller than that of the achiral elastic rings. The destabilizing effect of chirality, however, can be reduced by increasing the twisting rigidity to bending rigidity of filaments (twist-to-bend ratio).","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"189 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115479583","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 : 2021-12-20DOI: 10.15625/0866-7136/16613
Nguyen Van My, Le Anh Tien, Phan Hoang Nam, N. Q. Khánh, Chau Van Than, Phan Thanh Hoang
This study aims at numerically exploring the behavior of flow fields and nonlinear hydrodynamic coefficients of a horizontal cylinder beneath the free surface flow considering the effects of nonlinear surface waves and various cylinder shapes. The computational model is based on two-dimensional incompressible Navier-Stokes solvers along with the treatment of the free surface flow using the volume of fluid method. The effect of the turbulent flow is also considered by using the shear stress transport turbulence model. The simulation result of a benchmark case study of the submerged cylinder is first validated with available experiment data, where a mesh convergence analysis is also performed. Afterward, the flow fields and hydrodynamic force coefficients around the cylinder surface are analyzed, and the influences of various cylinder shapes and Reynolds numbers on the hydrodynamic coefficients are investigated. A state diagram representing the hydrodynamic behavior including stable and unstable stages is finally proposed; this is an important criterion for the practice design of submerged civil structures under the free surface flow.
{"title":"On the behavior of nonlinear hydrodynamic coefficients of a submerged cylinder beneath the water surface","authors":"Nguyen Van My, Le Anh Tien, Phan Hoang Nam, N. Q. Khánh, Chau Van Than, Phan Thanh Hoang","doi":"10.15625/0866-7136/16613","DOIUrl":"https://doi.org/10.15625/0866-7136/16613","url":null,"abstract":"This study aims at numerically exploring the behavior of flow fields and nonlinear hydrodynamic coefficients of a horizontal cylinder beneath the free surface flow considering the effects of nonlinear surface waves and various cylinder shapes. The computational model is based on two-dimensional incompressible Navier-Stokes solvers along with the treatment of the free surface flow using the volume of fluid method. The effect of the turbulent flow is also considered by using the shear stress transport turbulence model. The simulation result of a benchmark case study of the submerged cylinder is first validated with available experiment data, where a mesh convergence analysis is also performed. Afterward, the flow fields and hydrodynamic force coefficients around the cylinder surface are analyzed, and the influences of various cylinder shapes and Reynolds numbers on the hydrodynamic coefficients are investigated. A state diagram representing the hydrodynamic behavior including stable and unstable stages is finally proposed; this is an important criterion for the practice design of submerged civil structures under the free surface flow.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123094669","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 : 2021-12-20DOI: 10.15625/0866-7136/16710
N. T. Khiem, Nguyen Minh Tuan, P. Lien
The present paper deals with the concept of antiresonance in multiple cracked beams and application for multi-crack identification. First, governing equations for antiresonant frequency are conducted and used for both computing antiresonant frequencies versus crack parameters and measuring-loading colocation and identifying cracks by measured antiresonant frequencies. Then, a procedure is proposed for crack identification in cantilever beam by antiresonant frequencies based on the so-called crack scanning method. Theoretical development is illustrated by numerical examples.
{"title":"Crack identification in beam by antiresonant frequencies","authors":"N. T. Khiem, Nguyen Minh Tuan, P. Lien","doi":"10.15625/0866-7136/16710","DOIUrl":"https://doi.org/10.15625/0866-7136/16710","url":null,"abstract":"The present paper deals with the concept of antiresonance in multiple cracked beams and application for multi-crack identification. First, governing equations for antiresonant frequency are conducted and used for both computing antiresonant frequencies versus crack parameters and measuring-loading colocation and identifying cracks by measured antiresonant frequencies. Then, a procedure is proposed for crack identification in cantilever beam by antiresonant frequencies based on the so-called crack scanning method. Theoretical development is illustrated by numerical examples.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117256538","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 : 2021-12-15DOI: 10.15625/0866-7136/16507
Hiep Xuan Trinh, Ngoc Bich Nguyen, Sinh Truong Nguyen
This paper presents the effect of water’s temperature on the friction properties of materials used in marine propeller sliding bearing. Copper-Rubber and Copper-Capron, two common pairs of material in the shaft water-lubricated polymer bearing were chosen to conduct experiments with the pin-on-disc model. Various conditions including water temperature, stress, and sliding velocity were examined, their results showed that in the range 30 °C to 100 °C of water temperature, the frictional coefficient of both friction pairs were unchanged under the small stress and low sliding velocity (0.3 MPa and 0.9 m/s). While in the case of stress and sliding velocity were both high (0.6 MPa and 1.5 m/s), it increased significantly in a certain transition temperature range. This temperature range of the pair Copper-Rubber and Copper-Capron is 50 °C to 60 °C and 80 °C to 90 °C, respectively. The experiment’s results also pointed out that in these transition temperature ranges, the friction coefficient of two pairs was slightly influenced by the change in sliding velocity, whereas the stress change has an important impact on its values. Nonetheless, when the water temperature was below the transition range, the effect of the stress change on the friction coefficient was not significant. Thus, high water temperature is the main reason for the friction coefficient’s increase rather than the increase of the stress. This work is expected to broaden the understanding of the friction behavior of the water-lubricated polymer bearing.
{"title":"Experimental studying the effect of water temperature on friction properties of marine propeller sliding bearing","authors":"Hiep Xuan Trinh, Ngoc Bich Nguyen, Sinh Truong Nguyen","doi":"10.15625/0866-7136/16507","DOIUrl":"https://doi.org/10.15625/0866-7136/16507","url":null,"abstract":"This paper presents the effect of water’s temperature on the friction properties of materials used in marine propeller sliding bearing. Copper-Rubber and Copper-Capron, two common pairs of material in the shaft water-lubricated polymer bearing were chosen to conduct experiments with the pin-on-disc model. Various conditions including water temperature, stress, and sliding velocity were examined, their results showed that in the range 30 °C to 100 °C of water temperature, the frictional coefficient of both friction pairs were unchanged under the small stress and low sliding velocity (0.3 MPa and 0.9 m/s). While in the case of stress and sliding velocity were both high (0.6 MPa and 1.5 m/s), it increased significantly in a certain transition temperature range. This temperature range of the pair Copper-Rubber and Copper-Capron is 50 °C to 60 °C and 80 °C to 90 °C, respectively. The experiment’s results also pointed out that in these transition temperature ranges, the friction coefficient of two pairs was slightly influenced by the change in sliding velocity, whereas the stress change has an important impact on its values. Nonetheless, when the water temperature was below the transition range, the effect of the stress change on the friction coefficient was not significant. Thus, high water temperature is the main reason for the friction coefficient’s increase rather than the increase of the stress. This work is expected to broaden the understanding of the friction behavior of the water-lubricated polymer bearing.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124199862","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 : 2021-12-11DOI: 10.15625/0866-7136/16575
H. Tung, Dao Nhu Mai, V. T. Long
An analytical investigation on the nonlinear response of doubly curved panels constructed from homogeneous face sheets and carbon nanotube reinforced composite (CNTRC) core and subjected to external pressure in thermal environments is presented in this paper. Carbon nanotubes (CNTs) are reinforced into the core layer through uniform or functionally graded distributions. The properties of constituents are assumed to be temperature dependent and effective properties of CNTRC are determined using an extended rule of mixture. Governing equations are established within the framework of first order shear deformation theory taking into account geometrical imperfection, von Kármán–Donnell nonlinearity, panel-foundation interaction and elasticity of tangential edge restraints. These equations are solved using approximate analytical solutions and Galerkin method for simply supported panels. The results reveal that load carrying capacity of sandwich panels is stronger when boundary edges are more rigorously restrained and face sheets are thicker. Furthermore, elevated temperature has deteriorative and beneficial influences on the load bearing capability of sandwich panels with movable and restrained edges, respectively.
{"title":"Nonlinear response of doubly curved sandwich panels with CNT-reinforced composite core and elastically restrained edges subjected to external pressure in thermal environments","authors":"H. Tung, Dao Nhu Mai, V. T. Long","doi":"10.15625/0866-7136/16575","DOIUrl":"https://doi.org/10.15625/0866-7136/16575","url":null,"abstract":"An analytical investigation on the nonlinear response of doubly curved panels constructed from homogeneous face sheets and carbon nanotube reinforced composite (CNTRC) core and subjected to external pressure in thermal environments is presented in this paper. Carbon nanotubes (CNTs) are reinforced into the core layer through uniform or functionally graded distributions. The properties of constituents are assumed to be temperature dependent and effective properties of CNTRC are determined using an extended rule of mixture. Governing equations are established within the framework of first order shear deformation theory taking into account geometrical imperfection, von Kármán–Donnell nonlinearity, panel-foundation interaction and elasticity of tangential edge restraints. These equations are solved using approximate analytical solutions and Galerkin method for simply supported panels. The results reveal that load carrying capacity of sandwich panels is stronger when boundary edges are more rigorously restrained and face sheets are thicker. Furthermore, elevated temperature has deteriorative and beneficial influences on the load bearing capability of sandwich panels with movable and restrained edges, respectively.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124374341","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 : 2021-11-04DOI: 10.15625/0866-7136/16272
P. C. Vinh, D. X. Tung, N. T. Kiều
This paper deals with the reflection and transmission of P-waves at a very rough interface between two isotropic elastic solids. The interface is assumed to oscillate between two straight lines. By mean of homogenization, this problem is reduced to the reflection and transmission of P-waves through an inhomogeneous orthotropic elastic layer. It is shown that a P incident wave always creates two reflected waves (one P wave and one SV wave), however, there may exist two, one or no transmitted waves. Expressions in closed-form of the reflection and transmission coefficient have been derived using the transfer matrix of an orthotropic elastic layer. Some numerical examples are carried out to examine the reflection and transmission of P-waves at a very rough interface of tooth-comb type, tooth-saw type and sin type. It is found numerically that the reflection and transmission coefficients depend strongly on the incident angle, the incident wave frequency, the roughness and the type of interfaces.
{"title":"Reflection and transmission of P-waves at a very rough interface between two isotropic elastic solids","authors":"P. C. Vinh, D. X. Tung, N. T. Kiều","doi":"10.15625/0866-7136/16272","DOIUrl":"https://doi.org/10.15625/0866-7136/16272","url":null,"abstract":"This paper deals with the reflection and transmission of P-waves at a very rough interface between two isotropic elastic solids. The interface is assumed to oscillate between two straight lines. By mean of homogenization, this problem is reduced to the reflection and transmission of P-waves through an inhomogeneous orthotropic elastic layer. It is shown that a P incident wave always creates two reflected waves (one P wave and one SV wave), however, there may exist two, one or no transmitted waves. Expressions in closed-form of the reflection and transmission coefficient have been derived using the transfer matrix of an orthotropic elastic layer. Some numerical examples are carried out to examine the reflection and transmission of P-waves at a very rough interface of tooth-comb type, tooth-saw type and sin type. It is found numerically that the reflection and transmission coefficients depend strongly on the incident angle, the incident wave frequency, the roughness and the type of interfaces.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122622174","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 : 2021-11-01DOI: 10.15625/0866-7136/16393
Binh D. Pham, Truong V. Vu, Lien V. T. Nguyen, Cuong T. Nguyen, Hoe D. Nguyen, Vinh Phu Nguyen, Hung V. Vu
In this study, the retraction and solidification of a fluid filament are studied by a front-tracking method/finite difference scheme. The interface between two phases is handled by connected points (Lagrangian grid), which move on a fixed grid domain (Eulerian grid). The Navier-Stokes and energy equations are solved to simulate the problem. Initially, the fluid filament has a shape as half of a cylindrical capsule contact with a cold flat surface. We consider the effect of the aspect ratio (Ar) on the solidification of the fluid filament. It is found that an increase in the aspect ratio (Ar) in the range of 2 – 14 causes the retraction length to increase. The rate of the solidification of a fluid filament decreases when the Ar ratio increases. The solidification time, the solidification height and the tip angle of the fluid filament under the influence of the aspect ratio are also considered. After complete solidification, a small protrusion on the top of the solidified fluid filament is found.
{"title":"A numerical study of the solidification process of a retracting fluid filament","authors":"Binh D. Pham, Truong V. Vu, Lien V. T. Nguyen, Cuong T. Nguyen, Hoe D. Nguyen, Vinh Phu Nguyen, Hung V. Vu","doi":"10.15625/0866-7136/16393","DOIUrl":"https://doi.org/10.15625/0866-7136/16393","url":null,"abstract":"In this study, the retraction and solidification of a fluid filament are studied by a front-tracking method/finite difference scheme. The interface between two phases is handled by connected points (Lagrangian grid), which move on a fixed grid domain (Eulerian grid). The Navier-Stokes and energy equations are solved to simulate the problem. Initially, the fluid filament has a shape as half of a cylindrical capsule contact with a cold flat surface. We consider the effect of the aspect ratio (Ar) on the solidification of the fluid filament. It is found that an increase in the aspect ratio (Ar) in the range of 2 – 14 causes the retraction length to increase. The rate of the solidification of a fluid filament decreases when the Ar ratio increases. The solidification time, the solidification height and the tip angle of the fluid filament under the influence of the aspect ratio are also considered. After complete solidification, a small protrusion on the top of the solidified fluid filament is found.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114297434","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 : 2021-10-20DOI: 10.15625/0866-7136/16152
M. Nguyen, T. Bui, V. S. Lo, N. T. Nguyen
This work aims at presenting a novel four-node quadrilateral element, which is enhanced by integrating with discrete shear gap (DSG), for analysis of Reissner-Mindlin plates. In contrast to previous studies that are mainly based on three-node triangular elements, here we, for the first time, extend the DSG to four-node quadrilateral elements. We further integrate the fictitious point located at the center of element into the present formulation to eliminate the so-called anisotropy, leading to a simplified and efficient calculation of DSG, and that enhancement results in a novel approach named as "four-node quadrilateral element with center-point based discrete shear gap - CP-DSG4". The accuracy and efficiency of the CP-DSG4 are demonstrated through our numerical experiment, and its computed results are validated against those derived from the three-node triangular element using DSG, and other existing reference solutions.
{"title":"A 4-node quadrilateral element with center-point based discrete shear gap (CP-DSG4)","authors":"M. Nguyen, T. Bui, V. S. Lo, N. T. Nguyen","doi":"10.15625/0866-7136/16152","DOIUrl":"https://doi.org/10.15625/0866-7136/16152","url":null,"abstract":"This work aims at presenting a novel four-node quadrilateral element, which is enhanced by integrating with discrete shear gap (DSG), for analysis of Reissner-Mindlin plates. In contrast to previous studies that are mainly based on three-node triangular elements, here we, for the first time, extend the DSG to four-node quadrilateral elements. We further integrate the fictitious point located at the center of element into the present formulation to eliminate the so-called anisotropy, leading to a simplified and efficient calculation of DSG, and that enhancement results in a novel approach named as \"four-node quadrilateral element with center-point based discrete shear gap - CP-DSG4\". The accuracy and efficiency of the CP-DSG4 are demonstrated through our numerical experiment, and its computed results are validated against those derived from the three-node triangular element using DSG, and other existing reference solutions.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125496818","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 : 2021-09-30DOI: 10.15625/0866-7136/15879
Q. Nguyen, B. Diep, Duy Hung Nguyen, Van Bien Nguyen, Van Bo Vu, Qui Duyen Do
In this research, we focus on development of a new configuration of magneto-rheological fluid (MRF) based clutch (MRC) featuring a tooth-shaped disc with multiple teeth acting as multiple magnetic poles of the clutch. The tooth-shaped disc is placed in a clutch housing composed of the left housing and the right housing. The inner face the housing also has tooth shaped features mating with the teeth of the disc through the working MRF. Excitation coils are placed directly on stationary winding cores placed on both side of the clutch housing. An air gap of 0.3 mm is left between the housing and the winding cores to ensure the housing can freely rotate against the winding cores. After the introductory part, configuration of the MRC is introduced and the transmitted torque of the MRC is derived. An optimization process to minimize the overall volume of the proposed clutch, which can generate a required maximum braking torque, is then conducted. The optimal results show that the overall volume of the proposed MRC is significantly reduced compared to a referenced conventional MRC (0.159 m3 vs. 0.295 m3). A prototype of the proposed MRC is fabricated for experimental works and good agreement between the experimental results and simulated ones is archived.
在这项研究中，我们专注于开发一种基于磁流变液(MRF)的新型离合器(MRC)，该离合器具有齿形圆盘，多个齿作为离合器的多个磁极。齿形圆盘放置在由左壳体和右壳体组成的离合器壳体内。外壳的内表面还具有齿形特征，通过工作磁流变场与圆盘的齿配合。励磁线圈直接放置在固定绕组芯放置在离合器外壳的两侧。在外壳和绕组芯之间留有0.3 mm的气隙，以确保外壳可以自由旋转。在介绍部分之后，介绍了磁流变控制的结构，推导了磁流变控制的传递力矩。然后进行优化过程，以最小化所提出的离合器的总体体积，从而产生所需的最大制动扭矩。最佳结果表明，与参考的传统MRC相比，拟议MRC的总体体积显着减少(0.159 m3 vs. 0.295 m3)。制作了MRC的原型并进行了实验，实验结果与模拟结果吻合较好。
{"title":"Development of a novel MR clutch featuring tooth-shaped disc","authors":"Q. Nguyen, B. Diep, Duy Hung Nguyen, Van Bien Nguyen, Van Bo Vu, Qui Duyen Do","doi":"10.15625/0866-7136/15879","DOIUrl":"https://doi.org/10.15625/0866-7136/15879","url":null,"abstract":"In this research, we focus on development of a new configuration of magneto-rheological fluid (MRF) based clutch (MRC) featuring a tooth-shaped disc with multiple teeth acting as multiple magnetic poles of the clutch. The tooth-shaped disc is placed in a clutch housing composed of the left housing and the right housing. The inner face the housing also has tooth shaped features mating with the teeth of the disc through the working MRF. Excitation coils are placed directly on stationary winding cores placed on both side of the clutch housing. An air gap of 0.3 mm is left between the housing and the winding cores to ensure the housing can freely rotate against the winding cores. After the introductory part, configuration of the MRC is introduced and the transmitted torque of the MRC is derived. An optimization process to minimize the overall volume of the proposed clutch, which can generate a required maximum braking torque, is then conducted. The optimal results show that the overall volume of the proposed MRC is significantly reduced compared to a referenced conventional MRC (0.159 m3 vs. 0.295 m3). A prototype of the proposed MRC is fabricated for experimental works and good agreement between the experimental results and simulated ones is archived.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"238 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126358985","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 : 2021-09-09DOI: 10.15625/0866-7136/16118
H. Tung, P. T. Hiếu
This paper presents an analytical approach to investigate the buckling of sandwich cylindrical shells subjected to uniform temperature rise and external lateral pressure. Two sandwich models corresponding to carbon nanotube reinforced composite (CNTRC) face sheets and core layer are considered. The properties of all constitutive materials are assumed to be temperature dependent and effective properties of CNTRC are determined according to an extended rule of mixture. Governing equations are established using first order shear deformation theory and solved employing two-term form of deflection along with Galerkin method for simply supported edge shells. In order to account for practical situations of in-plane boundary condition, the elasticity of tangential constraint of boundary edges is included. Owing to temperature dependence of material properties, critical thermal loads are determined adopting an iteration process. Numerous parametric studies are carried out and interesting remarks are given. The study reveals that sandwich shell model with CNTRC core layer and homogeneous skins has considerably strong capacity of buckling resistance. Numerical results also indicate that tangential edge constraint has significant effects on critical loads, especially at elevated temperature. In addition, in the case of thermal load, an intermediate volume percentage of carbon nanotubes can confer the highest critical temperatures of sandwich shells.
{"title":"Thermal and thermomechanical buckling of CNT-reinforced composite sandwich cylindrical shells including elasticity of tangential edge restraint","authors":"H. Tung, P. T. Hiếu","doi":"10.15625/0866-7136/16118","DOIUrl":"https://doi.org/10.15625/0866-7136/16118","url":null,"abstract":"This paper presents an analytical approach to investigate the buckling of sandwich cylindrical shells subjected to uniform temperature rise and external lateral pressure. Two sandwich models corresponding to carbon nanotube reinforced composite (CNTRC) face sheets and core layer are considered. The properties of all constitutive materials are assumed to be temperature dependent and effective properties of CNTRC are determined according to an extended rule of mixture. Governing equations are established using first order shear deformation theory and solved employing two-term form of deflection along with Galerkin method for simply supported edge shells. In order to account for practical situations of in-plane boundary condition, the elasticity of tangential constraint of boundary edges is included. Owing to temperature dependence of material properties, critical thermal loads are determined adopting an iteration process. Numerous parametric studies are carried out and interesting remarks are given. The study reveals that sandwich shell model with CNTRC core layer and homogeneous skins has considerably strong capacity of buckling resistance. Numerical results also indicate that tangential edge constraint has significant effects on critical loads, especially at elevated temperature. In addition, in the case of thermal load, an intermediate volume percentage of carbon nanotubes can confer the highest critical temperatures of sandwich shells.","PeriodicalId":239329,"journal":{"name":"Vietnam Journal of Mechanics","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132455201","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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