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981.
设置桩支承的起重机轨道梁的扶壁码头结构形式,抗倾稳定性影响分析中应该考虑截桩力的稳定力矩。探讨了截桩力的产生机理和计算方法,结合工程对截桩力产生的稳定力矩的影响进行分析,结果表明,考虑截桩力稳定力矩具有一定的经济意义。 相似文献
982.
I. Youn J. Im M. Tomizuka 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2006,44(9):659-674
A 7-DOF full-car model with optimal active control suspension is utilized to evaluate the vehicle dynamic performances which are achieved through proposed controllers. The optimal controller, which includes the integral action for the suspension deflection, considerably improves the attitude control of a vehicle because the rolling and pitching motion in cornering and braking maneuvers are reduced, respectively. In the viewpoint of level control, the integral control acting on the suspension deflection results in the zero steady-state deflection in response to static body forces and ramp road input. The dynamic characteristics of the suspension control system are evaluated in terms of time domain and frequency domain. The simulations in the time domain demonstrate the advantages of the active suspension system obtained by penalizing the integral and derivative of suspension deflections and the derivative of roll and pitch angles in the performance index. The frequency characteristic curves obtained by simulations regarding integral action or derivative action show the increase of both ride comfort and road-holding performances by maximizing the use of suspension deflections. The potential of derivative control is shown by the performances of the car traveling over a bump and braking. 相似文献
983.
P. M. Siegrist P. R. Mcaree 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2006,44(12):921-937
Kalman inverse filtering is used to develop a methodology for real-time estimation of forces acting at the interface between tyre and road on large off-highway mining trucks. The system model formulated is capable of estimating the three components of tyre-force at each wheel of the truck using a practical set of measurements and inputs. Good tracking is obtained by the estimated tyre-forces when compared with those simulated by an ADAMS virtual-truck model. A sensitivity analysis determines the susceptibility of the tyre-force estimates to uncertainties in the truck's parameters. 相似文献
984.
985.
路基纵向裂缝是多年冻土地区道路的典型病害之一,严重影响了道路行驶质量和汽车运营安全.围绕该地区路基纵向裂缝的特点,提出了新建道路纵向裂缝的预防原则和具体防治对策,具有重要的工程应用价值. 相似文献
986.
987.
988.
Nam-Jin Lee 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2016,54(10):1491-1510
In railway vehicles, excessive sliding or wheel locking can occur while braking because of a temporarily degraded adhesion between the wheel and the rail caused by the contaminated or wet surface of the rail. It can damage the wheel tread and affect the performance of the brake system and the safety of the railway vehicle. To safeguard the wheelset from these phenomena, almost all railway vehicles are equipped with wheel slide protection (WSP) systems. In this study, a new WSP algorithm is proposed. The features of the proposed algorithm are the use of the target sliding speed, the determination of a command for WSP valves using command maps, and compensation for the time delay in pneumatic brake systems using the Smith predictor. The proposed WSP algorithm was verified using experiments with a hardware-in-the-loop simulation system including the hardware of the pneumatic brake system. 相似文献
989.
Qing Wu Xiangjian Yang Colin Cole Shihui Luo 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2016,54(9):1208-1225
This paper developed a new and simple approach to model polymer draft gears. Two types of polymer draft gears were modelled and compared with experimental data. Impact characteristics, in-train characteristics and frequency responses of these polymer draft gears were studied and compared with those of a friction draft gear. The impact simulations show that polymer draft gears can withstand higher impact speeds than the friction draft gear. Longitudinal train dynamics simulations show that polymer draft gears have significantly longer deflections than friction draft gears in normal train operations. The maximum draft gear working velocities are lower than 0.2?m/s, which are significantly lower than the impact velocities during shunting operations. Draft gears’ in-train characteristics are similar to their static characteristics but are very different from their impact characteristics; this conclusion has also been reached from frequency response simulations. An analysis of gangway bridge plate failures was also conducted and it was found that they were caused by coupler angling behaviour and long draft gear deflections. 相似文献
990.
列车交会篷布气动力分析 总被引:2,自引:0,他引:2
为解决目前一车苫盖2张货车篷布(简称X型篷布)存在的严重兜风现象与货物湿损问题,并检验新型篷布(简称D型篷布)的使用效果,基于不同装载与加固方案,通过实车试验,针对D型篷布与X型篷布在有绳网和无绳网12种情况下,测试了列车交会压力波和货车蓬布绳索拉力。测试结果表明:当80~120km·h-1速度下的货车与200~210km·h-1速度下的动车组交会时,动车组上感受的最大压力波幅值仅为577Pa,货车感受到的最大压力波幅值为715Pa;绳索最大值为1055N,出现在无网X型篷布的角绳上,满足相关规定要求;没有苫盖篷布绳网时,2种篷布兜风现象均较严重,同等速度下无绳网X型篷布逆向压缝篷布绳索拉力比顺向压缝的大40%左右;篷布绳网在降低篷布绳索气动力中发挥了重要作用,大部分工况下无绳网篷布绳索受到的气动力比有网的大50%~80%。可见,在相同工况下,D型篷布比X型篷布使用性能优良。 相似文献