In this work, the reliability and robustness of a nonlinear energy sink device concept are investigated. The system is studied and optimized in deterministic and probabilistic cases. It is also studied under various types of uncertainty modelings with different reliability based robust design optimization formulations. The obtained results reveal the sensitivity of the device to the input uncertainties. The optimal designs obtained with the formulation under uncertainties are very different from the deterministic optimal design. New system configurations are obtained which ensure robust, highly reliable designs. In addition, a comparison is made between the different formulations and a conclusion is drawn about the suitable formulations for such a problem.
{"title":"Robustness and reliability investigations on a nonlinear energy sink device concept","authors":"Oussama Braydi, C. Gogu, M. Paredes","doi":"10.1051/meca/2020075","DOIUrl":"https://doi.org/10.1051/meca/2020075","url":null,"abstract":"In this work, the reliability and robustness of a nonlinear energy sink device concept are investigated. The system is studied and optimized in deterministic and probabilistic cases. It is also studied under various types of uncertainty modelings with different reliability based robust design optimization formulations. The obtained results reveal the sensitivity of the device to the input uncertainties. The optimal designs obtained with the formulation under uncertainties are very different from the deterministic optimal design. New system configurations are obtained which ensure robust, highly reliable designs. In addition, a comparison is made between the different formulations and a conclusion is drawn about the suitable formulations for such a problem.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"45 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90690146","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}
Liang Hao, Zheng Wang, Guoyuan Zhang, Yangyang Zhao, Qingjuan Duan, Zhenni Wang, C. Yongqin, Tuanjie Li
Base oils containing different nanoparticles with varying concentrations are prepared, in which SiO2, TiO2 and ZnO (20 nm) nanoparticles are employed to improve the lubrication performance. Their tribological properties are evaluated on a ball-on-disk tribometer. The results show that the nano-additive lubricants exhibit a good friction reduction and anti-wear ability at the optimal concentration of 1.0 wt.%, in which SiO2 nanoparticles can reduce the coefficient of friction (COF) and the area of wear scar (AWS) by 45.6% and 35%, respectively. The SiO2 nanoparticles exhibit the best potential additive tested. The lubrication mechanisms of the nanoparticles can be attributed to the rolling, mending and the protective films.
{"title":"Tribological evaluation and lubrication mechanisms of nanoparticles enhanced lubricants in cold rolling","authors":"Liang Hao, Zheng Wang, Guoyuan Zhang, Yangyang Zhao, Qingjuan Duan, Zhenni Wang, C. Yongqin, Tuanjie Li","doi":"10.1051/meca/2019085","DOIUrl":"https://doi.org/10.1051/meca/2019085","url":null,"abstract":"Base oils containing different nanoparticles with varying concentrations are prepared, in which SiO2, TiO2 and ZnO (20 nm) nanoparticles are employed to improve the lubrication performance. Their tribological properties are evaluated on a ball-on-disk tribometer. The results show that the nano-additive lubricants exhibit a good friction reduction and anti-wear ability at the optimal concentration of 1.0 wt.%, in which SiO2 nanoparticles can reduce the coefficient of friction (COF) and the area of wear scar (AWS) by 45.6% and 35%, respectively. The SiO2 nanoparticles exhibit the best potential additive tested. The lubrication mechanisms of the nanoparticles can be attributed to the rolling, mending and the protective films.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"57 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79316169","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}
R. Esmaeilpour, Hyunki Kim, T. Park, F. Pourboghrat, Akshat Agha, F. Abu-Farha
In the last two decades, the advances of using computers in sheet metal forming processes have introduced a novel adjustable process known as incremental sheet forming (ISF) as an optimal method for fast prototyping and low numbers of production. Formability and deformation behavior of ISF process are highly affected by the selected process parameters, such as the toolpath, step size, tool diameter, feed rate, and lubrication. The purpose of this work was to study the effect of these process parameters as well as hardening law on single point incremental forming (SPIF) process. For this work, a truncated-cone geometry was considered as a target shape with 7075-O aluminum alloy sheets. The simulations were conducted with different process parameters, i.e., toolpath type, step size, tool size, feed rate, friction coefficient, and wall angle with respect to the tool force and moment, effective plastic strain distribution and thickness of the part. In addition, three types of hardening laws i.e., isotropic extended Voce type hardening law, combined isotropic-kinematic Chaboche type hardening laws with single and double back-stress terms were applied in the finite element simulation of SPIF process. A detailed comparison of these hardening laws' predictions was made with respect to the tool force and moment, effective plastic strain distribution and thickness of the part.
{"title":"Effect of hardening law and process parameters on finite element simulation of single point incremental forming (SPIF) of 7075 aluminum alloy sheet","authors":"R. Esmaeilpour, Hyunki Kim, T. Park, F. Pourboghrat, Akshat Agha, F. Abu-Farha","doi":"10.1051/meca/2020019","DOIUrl":"https://doi.org/10.1051/meca/2020019","url":null,"abstract":"In the last two decades, the advances of using computers in sheet metal forming processes have introduced a novel adjustable process known as incremental sheet forming (ISF) as an optimal method for fast prototyping and low numbers of production. Formability and deformation behavior of ISF process are highly affected by the selected process parameters, such as the toolpath, step size, tool diameter, feed rate, and lubrication. The purpose of this work was to study the effect of these process parameters as well as hardening law on single point incremental forming (SPIF) process. For this work, a truncated-cone geometry was considered as a target shape with 7075-O aluminum alloy sheets. The simulations were conducted with different process parameters, i.e., toolpath type, step size, tool size, feed rate, friction coefficient, and wall angle with respect to the tool force and moment, effective plastic strain distribution and thickness of the part. In addition, three types of hardening laws i.e., isotropic extended Voce type hardening law, combined isotropic-kinematic Chaboche type hardening laws with single and double back-stress terms were applied in the finite element simulation of SPIF process. A detailed comparison of these hardening laws' predictions was made with respect to the tool force and moment, effective plastic strain distribution and thickness of the part.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"39 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88656132","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}
Thomas Le Mézo, Gilles Le Maillot, Thierry Ropert, L. Jaulin, A. Ponte, B. Zerr
This paper presents the development made around the SeaBot, a new low-cost profiling float design for shallow water. We introduce a simplified dynamical model of the float and propose a state feedback depth controller coupled with an Extended Kalman Filter (EKF) to estimate model parameters. We show experimental results of the depth control that validate the model and the controller. We finally propose a loop design method to build low-cost floats by highlighting key design choices along with design rules.
{"title":"Design and control of a low-cost autonomous profiling float","authors":"Thomas Le Mézo, Gilles Le Maillot, Thierry Ropert, L. Jaulin, A. Ponte, B. Zerr","doi":"10.1051/meca/2020037","DOIUrl":"https://doi.org/10.1051/meca/2020037","url":null,"abstract":"This paper presents the development made around the SeaBot, a new low-cost profiling float design for shallow water. We introduce a simplified dynamical model of the float and propose a state feedback depth controller coupled with an Extended Kalman Filter (EKF) to estimate model parameters. We show experimental results of the depth control that validate the model and the controller. We finally propose a loop design method to build low-cost floats by highlighting key design choices along with design rules.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"18 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88975849","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 solution of tridiagonal system of equations using graphic processing units (GPU) is assessed. The parallel-Thomas-algorithm (PTA) is developed and the solution of PTA is compared to two known parallel algorithms, i.e. cyclic-reduction (CR) and parallel-cyclic-reduction (PCR). Lid-driven cavity problem is considered to assess these parallel approaches. This problem is also simulated using the classic Thomas algorithm that runs on a central processing unit (CPU). Runtimes and physical parameters of the mentioned GPU and CPU algorithms are compared. The results show that the speedup of CR, PCR and PTA against the CPU runtime is 4.4x,5.2x and 38.5x, respectively. Furthermore, the effect of coalesced and uncoalesced memory access to GPU global memory is examined for PTA, and a 2x-speedup is achieved for the coalesced memory access. Additionally, the PTA performance in a time dependent problem, the unsteady flow over a square, is assessed and a 9x-speedup is obtained against the CPU.
{"title":"Parallel Thomas approach development for solving tridiagonal systems in GPU programming − steady and unsteady flow simulation","authors":"M. Souri, P. Akbarzadeh, H. M. Darian","doi":"10.1051/meca/2020013","DOIUrl":"https://doi.org/10.1051/meca/2020013","url":null,"abstract":"The solution of tridiagonal system of equations using graphic processing units (GPU) is assessed. The parallel-Thomas-algorithm (PTA) is developed and the solution of PTA is compared to two known parallel algorithms, i.e. cyclic-reduction (CR) and parallel-cyclic-reduction (PCR). Lid-driven cavity problem is considered to assess these parallel approaches. This problem is also simulated using the classic Thomas algorithm that runs on a central processing unit (CPU). Runtimes and physical parameters of the mentioned GPU and CPU algorithms are compared. The results show that the speedup of CR, PCR and PTA against the CPU runtime is 4.4x,5.2x and 38.5x, respectively. Furthermore, the effect of coalesced and uncoalesced memory access to GPU global memory is examined for PTA, and a 2x-speedup is achieved for the coalesced memory access. Additionally, the PTA performance in a time dependent problem, the unsteady flow over a square, is assessed and a 9x-speedup is obtained against the CPU.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"62 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85624816","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}
Allison Poels, Xavier Collin, A. Benaissa, D. Poirel
This work examines the flow structure modes in the boundary layer and in the wake of a NACA0012 airfoil in static conditions at transitional chord-based Reynolds numbers (Rec), for small angles of attack (α). A laminar mode, with a laminar separation of the boundary layer and laminar Kármán streets in the wake, was first observed for Rec< 61400 andα= 0°. For 77 000 < Rec< 118600, which corresponds to a regime between laminar and transitional mode called subcritical mode, the boundary layer exhibited a long separation bubble reattached close to the trailing edge, and the wake showed a turbulent Kármán street. Finally, for higher Recandα, a critical transition mode consisted of a long bubble followed by a turbulent separation, and a less structured vortex street in the wake of the airfoil.
{"title":"Mode and regime identification for a static NACA0012 airfoil at transitional Reynolds numbers","authors":"Allison Poels, Xavier Collin, A. Benaissa, D. Poirel","doi":"10.1051/meca/2020094","DOIUrl":"https://doi.org/10.1051/meca/2020094","url":null,"abstract":"This work examines the flow structure modes in the boundary layer and in the wake of a NACA0012 airfoil in static conditions at transitional chord-based Reynolds numbers (Rec), for small angles of attack (α). A laminar mode, with a laminar separation of the boundary layer and laminar Kármán streets in the wake, was first observed for Rec< 61400 andα= 0°. For 77 000 < Rec< 118600, which corresponds to a regime between laminar and transitional mode called subcritical mode, the boundary layer exhibited a long separation bubble reattached close to the trailing edge, and the wake showed a turbulent Kármán street. Finally, for higher Recandα, a critical transition mode consisted of a long bubble followed by a turbulent separation, and a less structured vortex street in the wake of the airfoil.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"41 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81205059","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 aim of this work is to deepen the understanding of the aerodynamics of a diffusion flame in a rotary cement kiln. The kiln is a rotary with a cylindrical shaped, long and equipped with a burner, and it is the seat of a diffusion flame with an axisymmetric turbulent jet. The kiln has a capacity of 8,000 Nm3 to 13,000 Nm3 of natural gas and primary air at T = 25 °C which interacts with a secondary hot air volume at T = 800 °C. The aerodynamic modelling of the furnace is achieved using the turbulence model RNG k–ε, which is able to handle the turbulence and capture the vortex shedding process. The Ansys/Fluent code, based on the finite volume approach to solve the Reynolds averaged Navier-Stokes (RANS), was used in this study. The interactions between turbulence and diffusion flame were handled by the PDF (Probability Density Function) approach. The numerical simulations have been validated by experiments from the kiln considered. Based on the findings obtained, it is concluded that the recirculation zone seems of paramount importance when combustion is taken into account because the reverse flow improves the flame stability and affects the combustion efficiency. In addition, limiting the secondary air flow through the furnace is major to improve combustion and avoid disturbing the advancement of the material along the kiln.
这项工作的目的是加深对旋转水泥窑中扩散火焰的空气动力学的理解。窑是一个圆筒状、长且装有燃烧器的旋转体，它是扩散火焰的座位，具有轴对称湍流射流。窑的容量为8000 Nm3至13000 Nm3的天然气和T = 25°C的一次风，与T = 800°C的二次热风量相互作用。采用紊流模型RNG k -ε实现了炉膛的气动建模，该模型能够处理紊流并捕捉旋涡脱落过程。本文采用Ansys/Fluent程序，基于有限体积法求解Reynolds平均Navier-Stokes (RANS)。湍流与扩散火焰之间的相互作用采用概率密度函数方法进行处理。数值模拟结果与所考虑的窑炉试验结果一致。根据所获得的结果，得出结论，当考虑到燃烧时，再循环区似乎是最重要的，因为反向流动提高了火焰稳定性并影响了燃烧效率。此外，限制二次风通过炉膛是改善燃烧和避免干扰物料沿窑推进的主要原因。
{"title":"Aerodynamic control of a diffusion flame to optimize materials' transition in a rotary cement kiln","authors":"Mohamed Nial, L. Loukarfi, H. Naji","doi":"10.1051/meca/2020043","DOIUrl":"https://doi.org/10.1051/meca/2020043","url":null,"abstract":"The aim of this work is to deepen the understanding of the aerodynamics of a diffusion flame in a rotary cement kiln. The kiln is a rotary with a cylindrical shaped, long and equipped with a burner, and it is the seat of a diffusion flame with an axisymmetric turbulent jet. The kiln has a capacity of 8,000 Nm3 to 13,000 Nm3 of natural gas and primary air at T = 25 °C which interacts with a secondary hot air volume at T = 800 °C. The aerodynamic modelling of the furnace is achieved using the turbulence model RNG k–ε, which is able to handle the turbulence and capture the vortex shedding process. The Ansys/Fluent code, based on the finite volume approach to solve the Reynolds averaged Navier-Stokes (RANS), was used in this study. The interactions between turbulence and diffusion flame were handled by the PDF (Probability Density Function) approach. The numerical simulations have been validated by experiments from the kiln considered. Based on the findings obtained, it is concluded that the recirculation zone seems of paramount importance when combustion is taken into account because the reverse flow improves the flame stability and affects the combustion efficiency. In addition, limiting the secondary air flow through the furnace is major to improve combustion and avoid disturbing the advancement of the material along the kiln.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"3 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80888350","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}
Spline couplings are increasingly being studied because of their growing use, particularly in the field of electric cars. Due to clearances, geometrical obligations and elastic deformation, spline couplings operate mainly in slightly misaligned situations. From these kinds of situations, problems could appear such as vibrations or contact damages. The purpose of this article is to analyse the misalignment of splined couplings and the effects it induces. In order to identify behavioural trends, this work offers analytical approaches for estimating contact pressures in spline connections. In the chosen approach, the simplifying hypotheses necessary for equations are detailed as well as the various analytical modelling. Despites these assumptions, comparisons with pure numerical approaches illustrates the quality of analytical approach adopted in this paper. This method of modelling contact pressure allows the identification of the main mechanical factors to be identified including stiffness, thus deceasing problems due to misalignments.
{"title":"Contact pressure in misaligned spline couplings","authors":"Clément Dupertuis, J. Ligier","doi":"10.1051/meca/2020049","DOIUrl":"https://doi.org/10.1051/meca/2020049","url":null,"abstract":"Spline couplings are increasingly being studied because of their growing use, particularly in the field of electric cars. Due to clearances, geometrical obligations and elastic deformation, spline couplings operate mainly in slightly misaligned situations. From these kinds of situations, problems could appear such as vibrations or contact damages. The purpose of this article is to analyse the misalignment of splined couplings and the effects it induces. In order to identify behavioural trends, this work offers analytical approaches for estimating contact pressures in spline connections. In the chosen approach, the simplifying hypotheses necessary for equations are detailed as well as the various analytical modelling. Despites these assumptions, comparisons with pure numerical approaches illustrates the quality of analytical approach adopted in this paper. This method of modelling contact pressure allows the identification of the main mechanical factors to be identified including stiffness, thus deceasing problems due to misalignments.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"2017 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86738289","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}
D. Belmiloud, M. Lachi, H. Pron, F. Bolaers, J. Dron, X. Chiementin, Ali Laggoun
Many sources of heat can emanate from the operation of a rotating machine, and one of which is the friction among the different parts of the ball bearings. Over time, these frictions may lead to a tearing of matter of the rings or on the rolling elements that cause some type of degradation by flaking. Flaking, in turn, produces a repetitive shock as a new source of thermal energy. This work proposes a physical model for the study of the thermal heating of a ball bearing during operation. The resolution of the energy balance is achieved by the Nodal method where both the heating due to friction and the heat induced by the passage of the balls on defect are taken into account. The proposed thermal model is validated through an experimental thermal analysis. The obtained results show that the temperature increases in the position of defect ball ring with increasing rotational speed. The same results are obtained for the influence of radial load.
{"title":"Thermo-dynamical modelisation of the degradation of a ball bearing in variables use conditions","authors":"D. Belmiloud, M. Lachi, H. Pron, F. Bolaers, J. Dron, X. Chiementin, Ali Laggoun","doi":"10.1051/meca/2020083","DOIUrl":"https://doi.org/10.1051/meca/2020083","url":null,"abstract":"Many sources of heat can emanate from the operation of a rotating machine, and one of which is the friction among the different parts of the ball bearings. Over time, these frictions may lead to a tearing of matter of the rings or on the rolling elements that cause some type of degradation by flaking. Flaking, in turn, produces a repetitive shock as a new source of thermal energy. This work proposes a physical model for the study of the thermal heating of a ball bearing during operation. The resolution of the energy balance is achieved by the Nodal method where both the heating due to friction and the heat induced by the passage of the balls on defect are taken into account. The proposed thermal model is validated through an experimental thermal analysis. The obtained results show that the temperature increases in the position of defect ball ring with increasing rotational speed. The same results are obtained for the influence of radial load.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"47 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86442882","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}
Fangwei Xie, Jinxin Cao, Erming Ding, Kuaidi Wan, Xinshi Yu, Jun Ke, K. Gao
The thermodynamic study of the valve-controlled adjustable damping shock absorber is conducted in order to solve the problem of oil leakage caused by excessive temperature rise of shock absorber. In this paper, the temperature rise of the valve-controlled adjustable damping shock absorber is analyzed from the perspective of energy conservation. Combined with the theory of fluid mechanics, the damping heat model is established, and the heat dissipation model of the shock absorber is established based on heat convection, heat conduction and heat radiation. The corresponding thermal equilibrium equation is established on the basis of damping heat and heat dissipation. The effects of vibration velocity, outer diameter, thickness and length of reservoir cylinder, and wind velocity on its thermal performance have been investigated. Specifically, temperature after thermal equilibrium will grow with the increase of vibration velocity and thickness of reservoir cylinder and degrade with the increase of outer diameter, length of reservoir cylinder and wind velocity. The higher the balance temperature, the shorter time is required to arrive thermal equilibrium. The difference between the experimental and simulation values of oil temperature after thermal equilibrium was not more than 2 °C, which verified the correctness of the theoretical model, while the experimental value in the process of temperature rise lagged behind the simulation value, which was mainly caused by the cumulative error of step-by-step iteration and the mechanical hysteresis in the experiment. The conclusions obtained can provide some references for the design of shock absorbers.
{"title":"Temperature rise characteristics of the valve-controlled adjustable damping shock absorber","authors":"Fangwei Xie, Jinxin Cao, Erming Ding, Kuaidi Wan, Xinshi Yu, Jun Ke, K. Gao","doi":"10.1051/meca/2019084","DOIUrl":"https://doi.org/10.1051/meca/2019084","url":null,"abstract":"The thermodynamic study of the valve-controlled adjustable damping shock absorber is conducted in order to solve the problem of oil leakage caused by excessive temperature rise of shock absorber. In this paper, the temperature rise of the valve-controlled adjustable damping shock absorber is analyzed from the perspective of energy conservation. Combined with the theory of fluid mechanics, the damping heat model is established, and the heat dissipation model of the shock absorber is established based on heat convection, heat conduction and heat radiation. The corresponding thermal equilibrium equation is established on the basis of damping heat and heat dissipation. The effects of vibration velocity, outer diameter, thickness and length of reservoir cylinder, and wind velocity on its thermal performance have been investigated. Specifically, temperature after thermal equilibrium will grow with the increase of vibration velocity and thickness of reservoir cylinder and degrade with the increase of outer diameter, length of reservoir cylinder and wind velocity. The higher the balance temperature, the shorter time is required to arrive thermal equilibrium. The difference between the experimental and simulation values of oil temperature after thermal equilibrium was not more than 2 °C, which verified the correctness of the theoretical model, while the experimental value in the process of temperature rise lagged behind the simulation value, which was mainly caused by the cumulative error of step-by-step iteration and the mechanical hysteresis in the experiment. The conclusions obtained can provide some references for the design of shock absorbers.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"112 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75171611","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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