防撞活动护栏端部框架优化

为对某防撞活动护栏端部进行改进优化,结合碰撞试验数据,运用有限元仿真模拟计算手段开发出一种矩形管框架端部。结果表明,矩形管框架端部可承受1.1倍的试验载荷,相对于原设计结构性能优,加工方便,材料用量可减少21%。可见该结构满足应用要求,已经在实际工程中成功实施。     

A bottom-up solution for the multi-facility optimal pavement resurfacing problem

Transportation infrastructure management has been a subject of growing economic importance in recent years due to the magnitude of agency expenditures. Increasingly sophisticated methods have been developed to model pavement deterioration and solve for optimal management strategies. However, it is unclear whether these more complex methods are providing more useful results. This paper presents a simple approach for optimizing the frequency and intensity of resurfacing for multiple highway facilities. It builds upon existing optimization methods for the single-facility, continuous-state, continuous-time problem and corresponding results, which include a threshold structure for optimal solutions. This threshold structure allows for mathematical simplifications and for a straightforward optimization approach to be applied to the multi-facility case. The approach is bottom-up rather than top-down, preserving facility-specific features to develop informative budget allocation results. Application of the approach in a case study indicates that solutions are likely to be robust to deterioration model uncertainty, which is consistent with previous facility-level findings. In addition, the methodology is shown to be robust to the form of the deterioration model.     

微型汽车发动机凸轮型线仿真优化设计及应用研究

针对微型汽车发动机低速动力不足的问题,结合发动机整机性能分析软件和多体动力学分析软件,建立了原发动机整机性能模型和单阀系多体动力学分析模型。在准确模型的基础上对凸轮型线进行了结构设计,并选出了既能满足整机性能要求又能满足单阀系多体动力学要求的最优凸轮型线组。试验结果表明,该方法可以方便找出最优的凸轮型线范围,减少了试验次数,降低了开发成本。     

大型客车门窗口变形分析与优化

提出了大客车车身优化门窗对角线变形量的方法.通过对门窗对角线变形量的灵敏度分析结果进行适当处理,筛选出部分梁截面尺寸作为设计变量对车身结构进行了尺寸优化.优化结果表明,在质量略有增加的情况下,车身结构的模态特性基本保持不变,刚度特性得到大幅提升,优化后的车身结构满足了各项设计要求.     

船舶内燃机工作过程中颗粒横向迁移的实验研究

为了研究船舶内燃机工作过程中颗粒浓度的再分布问题，本文对层流流动中单个颗粒横向迁移的动力学机理进行了实验研究。采用自行研制的“CCD颗粒轨迹记录装置”记录了层流圆管入口段中单个颗粒的运动轨迹。实验表明，当颗粒超前于当地流体速度时，向管壁迁移；落后于当地流作速度时，向管心迁移。实验结果与理论分析一致。     

Studies on the block positioning metrics system for the hull erection stage

In ship hull production, the accuracy of management activities is extremely important. The block positioning operation in the erection stage is a key process in such management. The quality of the block positioning determines not only the accuracy of the final hull, but also the productivity and cost at the erection stage. We have previously proposed the basic concepts of computer-aided accuracy management. Accuracy management activities consist of "accuracy planning activities" and "accuracy measurement activities." Accuracy measurement activities involve checking and coping with inaccuracy. We have also proposed a system of accuracy measurement metrics: one is accuracy for completion (e.g., straightness, flatness), and the other is accuracy for construction (e.g., the relative joint shapes of each part). This paper explains the detailed accuracy metrics for a block positioning operation in the erection stage. The quality of the block positioning operation is estimated by this system: the accuracy of the completed hull can be evaluated by the concept of tolerance, and the accuracy of the construction process can be evaluated by the concept of labor costs. The prototype of this accuracy metrics system is then implemented. This metrics system is combined with the optimization software program iSIGHT to decide the best block positioning process. Then some examples of the block position optimizing process are shown. Received: November 2, 2001 / Accepted: December 6, 2001     

非线性汽车行驶平顺性模型的神经网络优化

本文运用离散生成随机路面输入的方法，在时城上对11自由度非线性整车行驶平顺性模型进行了分析研究，并在此 以径向基函数神经网络对悬架参数进行了优化计算。模型及算法合理准确，为汽车行驶平顺性的进一步研究提供了有价值的参考方法。     

汽车乘员安全约束系统的优化

本文利用ＭＡＤＹＭＯ软件建立了包括台车、安全带约束的乘员前碰仿真模型并通过试验验证了模型的正确性。利用该模型对乘员安全约束系统的优化问题进行了研究。对几种优化方法应用于乘员约束系统的效果进行了评价，提出了改进约束系统的建议。     

海洋工程结构中多管-板相贯的求交算法

本文综合分析了多管－板相贯的几何特点,并依据这些特点提出了多管－板相贯求交的一个通用算法,根据这一算法数控切管机成功地实现了这类坡口一次数控切割成形,极大地提高了生产效率。本文并给出了一个较为典型的算例。     

车用直喷柴油机微粒排放中SOF的来源分析

在冷起动、自由加速工况及3种转速50％负荷工况下，采用自行设计的袋式微粒采集系统对柴油机微粒进行采集，并用归一化法作为定量方法对色谱进行了定量分析。试验表明，冷起动、自由加速工况约有25％的有机可溶成分来自润滑油，稳态工况约有40％－60％的有机可溶成分来自润滑油。