隧道施工不良地质探地雷达超前探测全波形反演研究

为了解掌子面前方不良地质体赋存状况,保障工程施工安全,提出基于全波形反演的探地雷达隧道超前探测数据解译方法。首先,考虑隧道典型不良地质类型,建立溶洞、岩体裂隙和岩体破碎带等数值模型,进行正演模拟分析,总结典型不良地质体的地质雷达正演响应特征。其次,基于全波形反演方法对正演模拟数据进行处理,得到最优的相对介电常数分布,分析反演结果,并总结其相较于正演剖面图解译的优势。研究结果表明,全波形反演可以得到探测区域相对介电常数的较准确分布,得到的不良地质体形态与真实情况较为一致,成像效果明显优于原始雷达剖面图,提高了对不良地质体进行判断的直观性和准确性。     

面向设计的计算机辅助汽车装配工艺规划系统

从汽车的概念设计阶段就把装配可行性考虑其中,并且一致持续到批产以后。首先,在概念设计阶段,用专家系统对设计进行验证;然后,在设计开发阶段,对设计进行装配评估,检查是否满足装配的基本要求;装配可行性分析,对设计进行静态检查,装配路径生成,工具空间检查,和人机工程验证;紧固件检查,检查紧固件是否和标准一致,以降低紧固件的种类和数量;接着开始整车虚拟装配模拟,以发现设计中的错误,及时改进。最后生成装配工艺文件和特殊工装的设计要求。这样的面向设计的计算机辅助装配工艺规划系统,缩短了开发时间,降低了开发的成本,提高了开发的效率。     

基于DoIP的终检线模拟测试系统

随着汽车智能化和网联化发展,以太网技术越来越广泛应用到汽车领域。车载以太网的应用,对于主机厂的终检线诊断提出了新的要求,主机厂需要开发基于DoIP的车辆终检线诊断程序。文章介绍了一种基于DoIP的终检线模拟测试系统:基于ISO13400DoIP协议,利用专业的汽车总线仿真软件Vehicle SPY3模拟DoIP节点,搭建终检线台架,模拟DoIP的整车诊断,进行终线诊断程序的前期开发。     

基于三维数字场的船体表面测量定位标识系统研究

在介绍三维数字场的基础上,对构建基于三维数字场的船体表面测量定位标识系统的框架结构、测量系统、室内空间定位系统及标识划线执行装置系统开展了研究,重点对相应的原理、涉及的技术等方面进行探讨.在此基础上,以船舶表面敷设柔性矩形块的定位点标识作为应用对象,开发相关测量、定位、标识系统,实现在三维数字场中的完整原理性作业,验证提高作业精度和效率的可行性.     

Stability enhancement of a high-speed train bogie using active mass inertial actuators

In this study, a method regarding frame lateral vibration control based on the state feedback of an additional oscillator is proposed, so as to improve the bogie hunting stability. The multi-objective optimisation method (MOOP), with two objective functions of the stability index and control effort, is solved by the NSGA-II algorithm to obtain the feedback gains. The frame lateral vibration control can effectively improve the bogie hunting stability according to the linear and non-linear analysis of a high-speed train bogie, in which a fault of the yaw damper and time delay in the control system are considered. The effect of the oscillator suspension parameters and time delay on the system stability and robustness are analysed. The results show that the damped vibration frequency of the oscillator should be equal to the bogie hunting frequency, but a harder oscillator suspension can be used to improve the hunting critical speed margin of the bogie control system. However, just as how the feeding the frame states back directly, a hard oscillator suspension will lead to instability in the control system at a certain time delay. Therefore, the improvement of bogie hunting stability and reduction of control system stability must be considered when optimising the oscillator parameters. For the 350?km/h train bogie covered in this study, the optimal mass, natural frequency and damping ratio of the additional oscillator are acquired.     

Study on pattern time delay shift coding scheme

1 Introduction1 The underwater acoustic communications are needed for military affairs and commercial fields. There are lots of applications of underwater acoustic communications, such as in oceanographic data collection, exploration of natural undersea r…     

A numerical investigation of bubble dynamics based on the potential-flow theory

1 Introduction1 In the past, people researched into the underwater bubble dynamics by combining the theoretical analysis and experimental study, however, theoretical analysis is limited to simple and regular cases and the repeatability and alterability of…     

利用土工合成材料处理桥头跳车中加固段长度的确定方法

在确定利用土工合成材料处理桥头跳车中的加固段长度时,若按规范计算常出现较大的偏差,原因是规范只考虑土工合成材料对台后填土的加筋作用,而未考虑到加固段在道路正常使用时还起到了对正常路基与桥台差异沉降的过渡作用。通过算例比较可以看出在考虑了加固段在道路正常使用时对正常路基与桥台差异沉降的过渡作用所得的结果更为合理。故在设计中应结合考虑土工合成材料对台后填土的加筋和加固段对差异沉降的过渡这2个方面的作用,更为合理的进行设计。     

京杭运河边软土地基沉井施工技术

软土地质条件下,沉井的施工时易产生周边土体沉降、失稳、底涌、超沉等问题。该文通过杭州运河边丽水路沉井施工,对软土地基沉井施工技术进行探讨,希望能对今后软土地基上施工沉井起到一定的借鉴作用。     

上海长华路长桥主桥施工控制

该文介绍了上海长华路长桥主桥施工方案,介绍了其监控计算与控制方案,对中跨合龙可能产生误差的原因进行了分析,并对合龙误差进行预测,根据理论计算预先采取消除措施,同时,对施工监控结果进行了分析。