The transient finite element technique is applied, and a transient heat conduction model of wet brake friction disk is established. For obtaining the accurate heat flow density mathematic model and avoiding possibly i...The transient finite element technique is applied, and a transient heat conduction model of wet brake friction disk is established. For obtaining the accurate heat flow density mathematic model and avoiding possibly instable thermoelastic stress produced by the non uniform contact pressure of friction pair, a test method is applied to collect accurate contact pressure between the dual sheet steel and friction disk in the combining process. And then the heat-flow density and transient ther mo mechanical coupling simulation are analyzed. At the same time all possible boundary conditions are considered, such as the heat generation, heat conduction problem, relation between friction and contact, variation in load and heat change problem etc. The simulation results show that the me chanical model of thermo mechanical coupling can express well the dynamic characteristics of fric tion disk, and gives perfect reference for more study on thermoelastic distortion of brake friction pairs.展开更多
Aimed at the difficulty in revealing the vibration localization mechanism of mistuned bladed disks by using simple non-linear model,a mechanical model of the bladed disk with random mistuning of hysteretic dry frictio...Aimed at the difficulty in revealing the vibration localization mechanism of mistuned bladed disks by using simple non-linear model,a mechanical model of the bladed disk with random mistuning of hysteretic dry friction damping was established.Then,the incremental harmonic balance method was used to analyze the effects of the parameters of bladed disks,such as the mistuning strength of dry friction force,coupled strength,viscous damping ratio and friction strength,on the forced response of the bladed disks.The results show that the vibrational energy localization phenomenon turns up in the tuned bladed disks if the nonlinear friction damping exists,and the random mistuning of the dry friction force intensifies this kind of vibration localization.展开更多
By using a generalized Langevin equation to describe the vertieal oscillations of a general relativistic disk subjected to a memory-damped friction and a stochastic force, we derive the power spectrum density （PSD） ...By using a generalized Langevin equation to describe the vertieal oscillations of a general relativistic disk subjected to a memory-damped friction and a stochastic force, we derive the power spectrum density （PSD） of accretion disk oscillating luminosity by the method of Laplace transform, and discuss the influence of the system parameters on the resonant behavior in PSD curves. The results show that as the damping strength a and memory time τ of the friction increase, the variation of PSD with spectrum frequency f from monotonous decreasing to occurring maximums, and the phenomenon of a general stochastic resonance （SR） with a single peak and multi-peaks can be found in PSD curves. The radial distance parameter n, the mass M, and spin parameter a, of the black hole determine the inherent frequency of vertical oscillations in the disk, and they have significant influences on the SR phenomena in a system of black hole binaries.展开更多
In this paper,we firstly review the carbon layered surface prepared with electron cyclotron resonance (ECR) plasma sputtering. Secondly,the friction behavior of carbon layered surface under pin-on-disk testing is desc...In this paper,we firstly review the carbon layered surface prepared with electron cyclotron resonance (ECR) plasma sputtering. Secondly,the friction behavior of carbon layered surface under pin-on-disk testing is described. Furthermore,the contact stress evolution processes of layered surface with and without transfer layer during wear are given for understanding the contact mechanisms. Finally,a three-dimension (3D) local yield map of layered surface is introduced,which is useful to predict the possible contact mechanisms.展开更多
基金Supported by the National Basic Research Program of China("973"Program)(613002)
文摘The transient finite element technique is applied, and a transient heat conduction model of wet brake friction disk is established. For obtaining the accurate heat flow density mathematic model and avoiding possibly instable thermoelastic stress produced by the non uniform contact pressure of friction pair, a test method is applied to collect accurate contact pressure between the dual sheet steel and friction disk in the combining process. And then the heat-flow density and transient ther mo mechanical coupling simulation are analyzed. At the same time all possible boundary conditions are considered, such as the heat generation, heat conduction problem, relation between friction and contact, variation in load and heat change problem etc. The simulation results show that the me chanical model of thermo mechanical coupling can express well the dynamic characteristics of fric tion disk, and gives perfect reference for more study on thermoelastic distortion of brake friction pairs.
基金Project(2007CB707706) supported by the National Basic Research Program of China
文摘Aimed at the difficulty in revealing the vibration localization mechanism of mistuned bladed disks by using simple non-linear model,a mechanical model of the bladed disk with random mistuning of hysteretic dry friction damping was established.Then,the incremental harmonic balance method was used to analyze the effects of the parameters of bladed disks,such as the mistuning strength of dry friction force,coupled strength,viscous damping ratio and friction strength,on the forced response of the bladed disks.The results show that the vibrational energy localization phenomenon turns up in the tuned bladed disks if the nonlinear friction damping exists,and the random mistuning of the dry friction force intensifies this kind of vibration localization.
基金supported by the National Natural Science Foundation of China(Grant No.11045004)the Key Program of the Scientific Research Foundation of the Education Bureau of Hubei Province,China(Grant No.D20132603)
文摘By using a generalized Langevin equation to describe the vertieal oscillations of a general relativistic disk subjected to a memory-damped friction and a stochastic force, we derive the power spectrum density （PSD） of accretion disk oscillating luminosity by the method of Laplace transform, and discuss the influence of the system parameters on the resonant behavior in PSD curves. The results show that as the damping strength a and memory time τ of the friction increase, the variation of PSD with spectrum frequency f from monotonous decreasing to occurring maximums, and the phenomenon of a general stochastic resonance （SR） with a single peak and multi-peaks can be found in PSD curves. The radial distance parameter n, the mass M, and spin parameter a, of the black hole determine the inherent frequency of vertical oscillations in the disk, and they have significant influences on the SR phenomena in a system of black hole binaries.
基金National Natural Science Foundation of China(No.90923027No.51175405)
文摘In this paper,we firstly review the carbon layered surface prepared with electron cyclotron resonance (ECR) plasma sputtering. Secondly,the friction behavior of carbon layered surface under pin-on-disk testing is described. Furthermore,the contact stress evolution processes of layered surface with and without transfer layer during wear are given for understanding the contact mechanisms. Finally,a three-dimension (3D) local yield map of layered surface is introduced,which is useful to predict the possible contact mechanisms.
