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1.
    
Evaluation of vertical stress distribution in clay-loam soil using Smoothed-Particle Hydrodynamics-Finite Element Analysis (SPH-FEA) technique is presented in this research. The moist soil is modelled using the hydrodynamic elastic–plastic material and Murnaghan equation of state, while the tire is modelled using FEA in Visual Environment’s Pam-Crash software. Soil-tire interaction is performed using the node symmetric node to segment with edge treatment method. A single-wheel tester in a soil bin environment was utilized to provide experimental data. The objectives of the experimental test were to (1) calculate maximum subsoil stresses in the subsoil at 1 to 15 passes of a wheel with loads of 1, 2, 4, and 5 kN on soil with moisture levels of 0, 10, 17, and 24%.; (2) calibrate soil with different levels of moisture (3) compare predicted soil stresses with experiments. The maximum stress at 20 cm depth increased with increasing soil moisture and also with high levels of tire load. In contrast, successive traffic showed a decreasing effect on soil stress. The coefficient of determination 0.97 shows the predictions agreed very well with experiments. The moist soil-tire interaction model will be further used to analyze the soil stress in different soil depths and different forward velocity.  相似文献   

2.
The wheel-rail adhesion control for regenerative braking systems of high speed electric multiple unit trains is crucial to maintaining the stability,improving the adhesion utilization,and achieving deep energy recovery.There remain technical challenges mainly because of the nonlinear,uncertain,and varying features of wheel-rail contact conditions.This research analyzes the torque transmitting behavior during regenerative braking,and proposes a novel methodology to detect the wheel-rail adhesion stability.Then,applications to the wheel slip prevention during braking are investigated,and the optimal slip ratio control scheme is proposed,which is based on a novel optimal reference generation of the slip ratio and a robust sliding mode control.The proposed methodology achieves the optimal braking performancewithoutthewheel-railcontactinformation.Numerical simulation results for uncertain slippery rails verify the effectiveness of the proposed methodology.  相似文献   

3.
加速度计的交叉耦合对无陀螺惯性测量组合影响的研究   总被引:3,自引:1,他引:3  
研究了加速度计的交叉耦合系数的大小对惯性测量组合的影响,推导了存在交叉耦合系数的惯导方程,从方程中可以看出交叉耦合系数对导航精度的影响,最后通过仿真验证了这种影响。该的研究为无陀螺惯性测量组合的实际应用奠定了基础,并对加速度计的选用具有一定的指导意义。  相似文献   

4.
船体角形变是传递对准中的主要误差源,需要依靠测量仪器精确标定。根据姿态匹配方法使用两套激光陀螺组合体可以计算角形变。但是动态形变和船体运动角速度的交叉相关的观测耦合效应导致角形变的最优估计结果不准确,并且通过姿态匹配方法这种观测耦合效应是不能被准确测量的,需要结合其它角形变的测量信息进行计算。基于角速度匹配方法,研究了观测耦合效应,并得出其导致角形变估计的偏置误差,且受船体运动角速度调制的结论。通过补偿激光陀螺组合体测量的角速度,降低了观测耦合效应,得到了高精度的对准结果。仿真结果表明观测耦合效应主要导致了静态形变估计精度的不准确。  相似文献   

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