Study on Tire Dynamic Cornering Properties Using Experimental Modal Parameters

Based on the modeling of tire vertical characteristics and steady cornering properties, the model of tire nonsteady cornering is established in this paper using tire modal parameters extracted experimentally. In order to consider the influence of tire rolling effect on its cornering properties, the induced transfer function is introduced. The analytical formulae for calculation of transfer-function of lateral force and self-aligning torque with respect to lateral displacement and yaw angle are derived. The nonsteady cornering characteristics of tire under different loads can be calculated. The results of calculation are consistent with the experimental ones in the literature. The influence of rolling speed on tire cornering properties including the static case is analyzed. The nonsteady cornering properties in high frequency range are given by the model. The study demonstrates the consistency between steady and nonsteady tire modeling by using modal parameters.     

基于人工神经网络的公路黄土高边坡稳定性预测研究

文章介绍了BP网络模型的计算过程并对其性能进行了改进。在此基础上,分析了影响黄土高边坡稳定性的因素,包括土体的容重γ、粘聚力c、内摩擦角φ、孔隙水压力比γu,地震烈度,边坡坡比和边坡高度H。在对西部四省地区上百个黄土高边坡稳定性进行调查的基础上,结合典型的实测数据,应用改进的神经网络BP模型对其进行预测和评价研究。结果表明:改进的BP模型具有收敛快、数据输入方便等优点,预测结果相对传统方法来说更准确、可靠,具有一定的推广的价值。     

漳州战备大桥总体设计

漳州战备大桥的主桥采用主跨132．0m部分斜拉桥，引桥采用跨度32．0m的连续梁。介绍了该桥的总体设计，包括主桥方案比选，主、引桥设计，景观设计等内容。     

漳州战备大桥挂篮设计

漳州战备大桥主桥的梁幅宽达27．0m，为单箱三室结构，整个截面一次整体灌注成形。介绍其所采用的三角形组合梁式宽幅挂篮的设计构思、总体构造与结构分析计算。     

车用汽油机射流燃烧系统的研究进展

汽油机射流燃烧系统已有多年的研究开发和实践，经过反复考验，其优越性得到证实。本文从射流室的特殊结构特点出发，利用多通道光纤高速摄影照片和示功图分析并结合紊流燃烧理论，对射流燃烧过程的燃烧特性进行的研究，论证了其诸多方面的优越性。还介绍了目前的研究进展。     

Optimal ballast water exchange sequence design using symmetrical multitank strategy

The quality of the ballast water exchange scheme affects many aspects of a ship, including intact stability, structural strength, building and operational expenses, etc. This paper focuses on developing an optimization methodology for large-scale sequential ballast water exchange. The method of transversely symmetrical ballast water tanks being exchanged simultaneously is adopted, and the potentials of multiple tanks being exchanged at a time are explored. The mathematical model for the symmetrical ballast water exchange problem is built by minimizing the occurred maximum trims, maximum hull girder bending moments, and shearing forces as objectives, and the related safety assessment criteria as constraints. A multiobjective genetic algorithm with some operators specially designed for the problem is presented to obtain a set of approximate Pareto-optimal solutions for engineers to choose from. Finally, a real case study on the symmetrical ballast water exchange of a 176,000 DWT bulk carrier is conducted to illustrate the effectiveness of the proposed approach.     

狮岭高架桥改建结构选型及设计探讨

针对狮岭高架桥扩建期间不能中断交通的要求,综合考虑施工阶段交通流的转换、施工工艺、原路基利用率、工程造价等因素的影响,通过方案比选,确定最优的上、下构方案。     

汽车动力传动系统匹配研究

汽车动力性、经济性的好坏很大程度上取决于汽车动力传动系统合理匹配的程度,发动机与传动系的合理匹配将显著降低汽车的燃油消耗并可获得较好的动力性.为改善发动机与传动系参数匹配不当的现状,本文以传动系参数给定,优选发动机参数为方向,对汽车动力传动系统进行了匹配研究.结果表明,通过优化匹配,汽车的动力性、经济性均得到一定的提高.     

模糊-PID控制在绞吸船水下泥泵自动调速中的应用

绞吸挖泥船装驳施工中,操作人员频繁调节水下泥泵电机转速以稳定管路内泥浆流速。针对这一问题,采用模糊-PID技术设计水下泥泵电机自动调速控制系统。该控制方法以流速作为自变量,以泥泵转速作为因变量,并将吸入真空、泥泵机功率及泥浆浓度作为安保条件,可以保证在装驳施工过程中泥浆流速持续维持在设定区间内。实际应用表明,模糊-PID控制在水下泥泵调速过程中具有反应快速、控制精准、鲁棒性好等特点,具有较好的推广价值。     

汽车车身热冲压成型技术的应用和质量控制综述

阐述了热冲压成型技术的发展趋势,分析热成型高强钢材在汽车白车身中的应用情况,介绍了热冲压成型技术的工艺原理及实施过程。同时从系统设备匹配、板料和模具匹配以及工艺设计及控制过程等多个角度分析,深入探讨热冲压制件的质量影响因素;以及在实际生产应用中,热冲压成型技术一些常见的工艺缺陷和产生原因,并且从质量控制角度针对缺陷问题提出了改善措施。