The vehicles with high gravity centre are more prone to roll over. The paper deals with a method of dynamics analysis of fire engines which is an example of these types of vehicle. Algorithms for generating the equati...The vehicles with high gravity centre are more prone to roll over. The paper deals with a method of dynamics analysis of fire engines which is an example of these types of vehicle. Algorithms for generating the equations of motion have been formulated by homogenous transformations and Lagrange＇s equation. The model presented in this article consists of a system of rigid bodies connected one with another forming an open kinematic chain. Road maneuvers such as a lane change and negotiating a circular track have been presented as the main simulations when a car loses its stability. The method has been verified by comparing numerical results with results obtained by experimental measurements performed during road tests.展开更多
The non-linear wheel-rail motional model is the first research breakthrough I have made in the field of vehicle system dynamics. The main external interference to a vehicle system in rail-borne transportation comes fr...The non-linear wheel-rail motional model is the first research breakthrough I have made in the field of vehicle system dynamics. The main external interference to a vehicle system in rail-borne transportation comes from the dynamic interaction between the wheel and the rail. To determine the forces exerted on the rail-contacting patches of a railcar is known to be one of the most complicated problems in rail haulage, expecially in its unsaturated state, i.e. before overall sliding occurs. Since the 1960s, many scholars, including K.L. Johnson and J.J.Kalker, have considered it a problem in rolling contact mechanics. However, none of the presented展开更多
Static strength finite element analysis was conducted to decrease the weight of a skeleton vehicle＇s frame. Results indicated that the maximum stress occurs on the front beam ＇s variable section area. Dynamic sensit...Static strength finite element analysis was conducted to decrease the weight of a skeleton vehicle＇s frame. Results indicated that the maximum stress occurs on the front beam ＇s variable section area. Dynamic sensitivity analysis elucidated the relationship between the maximum stress and the thickness of a particular beam,e. g.,top,middle,and bottom beam. Displacement was analyzed by the key part that influenced the maximum stress. Finally,the new plan using BS960 super-high-strength beam steel and the preferred beam thickness was compared with the original plan. New combinations of beam thickness were introduced on the basis of different purposes; the maximum responding light w eight ratio was 21%.展开更多
In order to control the low frequency vibration of railway vehicles, a vertical two degrees of freedom(2DOF) low frequency dynamic vibration absorber(DVA) based on acceleration is proposed. Parameters of the dynamic v...In order to control the low frequency vibration of railway vehicles, a vertical two degrees of freedom(2DOF) low frequency dynamic vibration absorber(DVA) based on acceleration is proposed. Parameters of the dynamic vibration absorber are put forth to control the low frequency vibration of car body bouncing and pitching. Next, the acceleration power spectrum density(PSD)and ride quality of the car body are calculated based on the pseudo excitation method(PEM) and covariance algorithm,respectively. According to the requirement of 2DOF low frequency DVA, the isolators with high static low dynamic stiffness(HSLDS) are designed. A high-speed train dynamic model containing HSLDS isolators is established to validate the effects on the car body vibration. The results reveal that the 2D low frequency DVA can significantly reduce the vibration of the car body bouncing and pitching. Thus, the ride quality of the vehicle is increased, and passenger comfort is improved.展开更多
基金supported by National Science Centre in Cracow under doctoral research grant 0630/B/T02/2011/40
文摘The vehicles with high gravity centre are more prone to roll over. The paper deals with a method of dynamics analysis of fire engines which is an example of these types of vehicle. Algorithms for generating the equations of motion have been formulated by homogenous transformations and Lagrange＇s equation. The model presented in this article consists of a system of rigid bodies connected one with another forming an open kinematic chain. Road maneuvers such as a lane change and negotiating a circular track have been presented as the main simulations when a car loses its stability. The method has been verified by comparing numerical results with results obtained by experimental measurements performed during road tests.
文摘The non-linear wheel-rail motional model is the first research breakthrough I have made in the field of vehicle system dynamics. The main external interference to a vehicle system in rail-borne transportation comes from the dynamic interaction between the wheel and the rail. To determine the forces exerted on the rail-contacting patches of a railcar is known to be one of the most complicated problems in rail haulage, expecially in its unsaturated state, i.e. before overall sliding occurs. Since the 1960s, many scholars, including K.L. Johnson and J.J.Kalker, have considered it a problem in rolling contact mechanics. However, none of the presented
文摘Static strength finite element analysis was conducted to decrease the weight of a skeleton vehicle＇s frame. Results indicated that the maximum stress occurs on the front beam ＇s variable section area. Dynamic sensitivity analysis elucidated the relationship between the maximum stress and the thickness of a particular beam,e. g.,top,middle,and bottom beam. Displacement was analyzed by the key part that influenced the maximum stress. Finally,the new plan using BS960 super-high-strength beam steel and the preferred beam thickness was compared with the original plan. New combinations of beam thickness were introduced on the basis of different purposes; the maximum responding light w eight ratio was 21%.
基金supported by the National Natural Science Foundation of China(Grant No.51805373)
文摘In order to control the low frequency vibration of railway vehicles, a vertical two degrees of freedom(2DOF) low frequency dynamic vibration absorber(DVA) based on acceleration is proposed. Parameters of the dynamic vibration absorber are put forth to control the low frequency vibration of car body bouncing and pitching. Next, the acceleration power spectrum density(PSD)and ride quality of the car body are calculated based on the pseudo excitation method(PEM) and covariance algorithm,respectively. According to the requirement of 2DOF low frequency DVA, the isolators with high static low dynamic stiffness(HSLDS) are designed. A high-speed train dynamic model containing HSLDS isolators is established to validate the effects on the car body vibration. The results reveal that the 2D low frequency DVA can significantly reduce the vibration of the car body bouncing and pitching. Thus, the ride quality of the vehicle is increased, and passenger comfort is improved.
