共查询到19条相似文献,搜索用时 156 毫秒
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针对现有的道路纵断面计算机辅助设计方法,该文对纵断面设计特性进行分析,提出了基于夹点拖动的纵断面设计动态拉坡新方法,并介绍了Auto CAD.NET API夹点强制协议的技术原理,以及纵断面切线夹点和竖曲线夹点的设置方法,对道路纵断面设计利用计算机科技发展新技术进行了研究探索。 相似文献
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运用最小二乘法对道路中心线的纵断面地面线进行分段直线拟合,建立最佳纵坡线方程,从而得到最小填挖方数量的道路纵坡设计线,再用设计规范的坡度和坡长限制以达到设计纵坡合理经济的目的。 相似文献
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为改变现有改建道路纵断面设计软件拉坡设计人工耗时长、随意性大、主观性强、设计方案参差不齐的状况,本文首次提出了基于粒子群算法的改建道路纵断面自动设计,以提高设计效率、减少工程投资。文章在满足相关规范、路面改造方案前提下,以改造纵断面填挖方高度总和最小为目标函数,以纵坡长度、纵向坡度、竖曲线半径为约束条件,以变坡点的里程、高程为变量,利用粒子群算法原理,构建了基于粒子群算法的改建道路纵断面自动设计模型。研究结果表明:该设计模型达到了改建道路纵断面自动适应贴合现状道路高程、路面改造工程量最小的目的,当粒子群算法迭代次数达到400多次时,粒子适应度函数趋于收敛,当迭代次数设为500次时,可以获得满意的成果。实例验证表明:与传统的人工设计相比,算法自动设计的效率更高,自动设计过程仅需2~3s,拟合原地面线的效果更好,能节省近一半的路面加铺工程量,优化设计效果显著。基于粒子群算法的改建道路纵断面自动设计,可为道路改造设计及设计咨询提供了理论基础与技术支持。 相似文献
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纵断面优化设计是公路优化设计中一个重要的组成部分,遗传算法是一种高效的全局寻优算法。介绍了用遗传算法实现纵断面优化设计的具体方法步骤,并编制出了计算机应用程序。经输入公路原始数据进行实例计算,取得了令人满意的结果,证明了遗传算法在纵断面优化设计中的可行性及全局寻优的性能。 相似文献
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余豫新 《筑路机械与施工机械化》2013,(11):76-80
系统分析了纵断面设计的关键因素,并且结合某工程实例,为多约束条件的复杂纵断面设计提供了思路和方法;通过研究评价指标与评价方法的对应关系,提出了基于DEA方法的纵断面方案定量评价方法,解决了以往定性选择纵断面方案时易产生的主观性、片面性的问题. 相似文献
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结合参与郑西、武广客运专线设计体会,就高速客运专线线路设计执行《京沪高速铁路设计暂行规定》中的若干问题,提出探讨性建议。包括:线路平面设计的最大曲线半径选用、缓和曲线长度及曲线超高设置;线路纵断面设计的最大坡度、最小坡段长度、坡段连接:平、纵断面组合设计等。 相似文献
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为了设计直线齿形孔插齿刀,根据共轭齿形原理,运用齿廓法线法建立工件齿形和刀具齿形的关系式,依据工件和刀具接触条件,由已知工件齿形坐标求出刀具齿形坐标,设计出了刀具齿形。用最小二乘法求出了刀具拟合直线,并对拟合直线进行了修正,保证了修正后的创成表面与原拟合直线创成表面相吻合。通过实践证明,利用设计的插齿刀在插齿机上加工直线齿形孔,不但效率高,而且被加工零件的齿形精度达到了图纸要求。 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(10):1619-1639
Inspired by a manufacturing process of switch rails for railway turnouts, a method for the optimisation of switch rail profile geometry is presented. The switch rail profile geometry is parameterised with four design variables to define a B-spline curve for the milling tool profile, and two design variables to prescribe the deviation from the nominal vertical path of the milling tool. The optimisation problem is formulated as a multi-objective minimisation problem with objective functions based on the contact pressure and the energy dissipation in the wheel–rail contact. The front of Pareto optimal solutions is determined by applying a genetic type optimisation algorithm. The switch rail profile designs are evaluated by simulations of dynamic train–turnout interaction. It is concluded that the obtained set of Pareto optimal solutions corresponds to a rather small variation in design variables where increased profile height and increased profile shoulder protuberance are preferred for both objectives. The improvement in the objectives comes at the cost of an earlier wheel transition to the switch rail and thus increased vertical loading at a thinner rail cross-section. The performance of the optimised geometry is evaluated using a set of 120 measured wheel profiles, and it is shown that the optimised geometry reduces damage also for this large load collective. It is concluded that accurate limits on switch rail loading need to be established to determine the feasible design space for switch rail geometry optimisation. 相似文献
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Christian Gorges Kemal Öztürk Robert Liebich 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2018,56(8):1289-1314
This publication presents a three-part road classification system that utilises the vehicle's onboard signals of two-wheeled vehicles. First, a curve estimator was developed to identify and classify road curves. In addition, the curve estimator continuously classifies the road curviness. Second, the road slope was evaluated to determine the hilliness of a given road. Third, a modular road profile estimator has been developed to classify the road profile according to ISO 8608, which utilises the vehicle's transfer functions. The road profile estimator continuously classifies the driven road. The proposed methods for the classification of curviness, hilliness, and road roughness have been validated with measurements. The road classification system enables the collection of vehicle-independent field data of two-wheeled vehicles. The road properties are part of the customer usage profiles which are essential to define vehicle design targets. 相似文献
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在对汽车外形的局部改型中,由于逆向设计具有设计精度高、开发周期短及节约成本等优点,逐渐得到厂家的广泛采用。文章根据原型车前后保险杠造型,运用逆向工程原理以及CATIA软件中的模块构建出新的保险杠造型,依据曲线几何连续性条件,利用曲面断面线法、斑马线法及曲面反射性分析法来评价曲面的质量。最终得到更加美观的轿车保险杠外表面造型。该方法大大提高了轿车外表面改型的开发效率。 相似文献
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客车燃油经济性计算软件的开发与运用 总被引:1,自引:0,他引:1
在客车开发设计阶段需要对其燃油经济性进行预测和估算,通过常规计算所得的估算值与试验值相比较存在数值偏小的问题。中分析了客车计算燃油消耗值偏小的主要原因,通过对发动机万有特性曲线的拟合,以及对发动机功率的修正,利用最小二乘法、高斯-赛得尔迭代法等计算方法,编制了燃油经济性计算软件,利用该软件计算得到的燃油值能较好地接近试验值。 相似文献
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J. E. Dzielski J. K. Hedrick 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1984,13(6):315-337
The effects of track irregularities and wheel profile on the amount of energy dissipated in railroad freight vehicles is examined. A nonlinear computational model is used to determine the average dissipation in the vehicle suspension and the wheel/rail contact patches. This dissipation is a component of the total resistance force acting on the vehicle. Parametric results are presented showing the effects of track geometry, wheel profile, suspension design, and hunting on train resistance. Track geometry studies consider the effects of track quality and curving. The AAR 1:20 wheel profile and the Heumann wheel profile are compared under various operating conditions. Compared with the Heumann profile, the AAR 1:20 profile is shown to have lower average resistance on good quality tangent track, but higher average resistance in steady curves. A trade-off exists between the two profiles when dynamic curve entry is considered. 相似文献