排序方式: 共有72条查询结果,搜索用时 109 毫秒
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阐述在Delphi中通过ODBC方式,Formula One与数据库联结的建立方法,结合例程讨论了数据文件的读写、数据交换、格式设置及报表处理技巧,为Delphi与第三方控件的集成提供一种思路. 相似文献
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Magic Formula轮胎模型参数辨识的一种混合优化方法 总被引:1,自引:0,他引:1
Magic Formula(MF)轮胎模型能够准确描述轮胎的侧偏特性,广泛应用于车辆动力学的研究。由于MF轮胎模型参数多,且高度非线性,从大量的试验数据中准确辨识这些参数相当困难。提出一种基于遗传算法和数值优化算法的混合优化方法,采用由粗到精的辨识过程,先利用遗传算法得出近似最优解,再利用数值优化算法辨识出精确的参数。利用辨识出的参数计算轮胎的侧偏特性,计算结果与试验数据吻合良好,表明该方法是辨识MF轮胎模型参数的有效手段。 相似文献
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The vortex-induced vibrations (VIV) of two flexible circular cylinders in a tandem configuration were studied numerically for spacing ratios ranging from 6 to 18 and the reduced velocities ranging from 2.35 to 12.59. The VIV response amplitude, response frequency, fluid force, pressure distribution and vortex structure of the tandem cylinders with different spacing ratios under different reduced velocities were compared. The results indicate that there is a great difference between the lift forces on the downstream and upstream cylinders. The lift coefficient of the downstream cylinder undergoing the wake-induced vibrations (WIV) is larger than that of the upstream cylinder, and the dominant frequency curves of the lift coefficients of the upstream and downstream cylinders separate. It can be found that the length and intensity of the wake are quite different under different reduced velocities and spacing ratios, and the reattachment positions between the wake and the downstream cylinder are different, which leads to a great change in the flow around the downstream cylinder and have a great effect on the wake-induced lift force on the downstream cylinder. Considering these factors, an empirical model for the wake-induced lift force on a cylinder with low mass ratio was proposed and verified. 相似文献
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关于细化铁路曲线上建筑限界加宽的建议 总被引:1,自引:0,他引:1
通过分析某中间站低站台与SS9G型机车脚蹬刮擦事故,指出铁路曲线上建筑限界垂向加高及降低的重要性。根据《铁路技术管理规程》和GB146.2—1983标准轨距铁路建筑限罗酚相关规定,建议加入铁路曲线建筑限界垂向加高及降低的规定和计算公式,细化曲线上建筑限界加宽办法。 相似文献
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A. J. Tremlett D. J. N. Limebeer 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2016,54(10):1448-1473
Variations in track temperature, surface conditions and layout have led tyre manufacturers to produce a range of rubber compounds for race events. Each compound has unique friction and durability characteristics. Efficient tyre management over a full race distance is a crucial component of a competitive race strategy. A minimum lap time optimal control calculation and a thermodynamic tyre wear model are used to establish optimal tyre warming and tyre usage strategies. Lap time sensitivities demonstrate that relatively small changes in control strategy can lead to significant reductions in the associated wear metrics. The illustrated methodology shows how vehicle setup parameters can be optimised for minimum tyre usage. 相似文献
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H. Nozaki 《International Journal of Automotive Technology》2008,9(3):307-315
Because Formula cars are lighter than ordinary cars, the optimal settings for this type of car are thought to be different
from those of a ordinary car. The front and rear weight distribution ratio of a vehicle is an important parameter that exerts
a significant influence on critical cornering. The tendency of a ordinary car to under-steer during critical cornering is
determined by the front and rear weight distribution ratio of the vehicle. Specifically, when the front of an ordinary FR
(front-engine, rear wheel drive) vehicle is slightly heavier than the rear, the car tends to understeer during critical cornering.
However, the optimal weight distribution ratio for critical cornering is not obvious for a formula car because of its lightness.
This observation was investigated using a driving course similar to a real driving course to perform a maximum speed cornering
simulations. It was found that a front to rear weight distribution ratio of 40:60 resulted in the fastest lap time. This ratio
also gave the best results in the maximum-speed driving experiment performed using a driving simulator. Moreover, the maximum
lateral acceleration during turning, the driving force, and the load movement of the inside and outside wheels was calculated
using experimental driving force data and the concept of a tire friction circle. As a result, driving mechanics have been
determined for a vehicle having a front/rear weight distribution ratio of 40:60 while traveling at maximum speed. 相似文献
27.
A new approach based on Bayesian theory is proposed to determine the empirical coefficient in soil settlement calculation. Prior distribution is assumed to be uniform in [0.2,1.4]. Posterior density function is developed in the condition of prior distribution combined with the information of observed samples at four locations on a passenger dedicated line. The results show that the posterior distribution of the empirical coefficient obeys Gaussian distribution. The mean value of the empirical coefficient decreases gradually with the increasing of the load on ground, and variance variation shows no regularity. 相似文献
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文章针对砂砾地层电力顶管施工引起的地面变形开展研究。首先,基于现有散粒土的沉降理论计算公式,进行某砂砾地层电力隧道顶管施工引起地面变形的理论计算和分析;其次,通过理论分析和现场实测,得到砂砾地层顶管施工引起的地面变形规律;最后,在现有理论计算公式和监测数据的基础上,利用规划求解,提出适用于砂砾地层顶管施工引起地面变形的沉降槽宽度系数计算公式。研究结果表明,土体损失是引起地面沉降的主要影响因素,沉降计算时必须考虑土体损失在顶进过程中的动态变化;修正沉降槽宽度系数计算公式能够较好地适用于砂砾地层中顶管施工引起的地面沉降计算。 相似文献
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