欧Ⅳ标准催化转换器的结构设计

将催化转换器安装在发动机排气歧管出口位置,可以使催化剂快速起燃,充分发挥某些配方的催化剂效能,这被执行欧III和欧IV排放标准的车辆广泛应用。从催化转换器布置的角度,介绍这种催化转换器的结构设计,比较了布置方案,并对催化转换器中的零件如进气端管、壳体总成、出气端锥以及封装方案的设计要点作了描述。论述了该型催化转换器的气体流动特性、温度分布和塑性应变分布。     

轮胎噪音的噪音特性研究

为了从路面与车轮接触方面研究如何降低交通噪音,文章从声学基础概念入手,结合人耳听觉特性,从现场测量和实验室测量两方面对轮胎噪音的声学特性进行了分析,最后得出低噪音路面设计中几个重要指标的建议取值。     

面波技术在滑坡勘察中的应用

面波技术在工程勘察及岩土工程检测中得到了较为广泛的应用,岩土工程勘察、路基压实质量检测及地基承载力等测试应用研究较多。运用面波技术对渝邻路的大湾滑坡进行了勘察,通过时域信号分析、频散曲线和波速云图3种判定方法查明了滑坡的滑动面。与钻孔资料对比,两者的结果较为一致。     

体外预应力简支梁的动力性能分析

为了解体外预应力索对结构动力性能的影响,针对简支梁的体外预应力的一般形式,文章采用能量法建立了体外预应力简支梁桥的一阶固有振动方程,对采用体外预应力的简支梁桥在预应力索和梁共同作用下的动力性能进行了研究。通过数值算例验证了体外预应力对简支梁桥振动频率和振动模态的影响。分析结果表明体外预应力简支梁的振动特征与梁端受有外力后的振动特征是不同的,体外预应力对改善梁体的动力性能没有显著效果。     

土基回弹模量分布特征的研究

根据一组实测的土基回弹模量值，采用概率理论对实测值的算术值和对数值频率分布进行比较分析，得出土基回弹模量具有显著的对数正态分布特征。     

射频模块技术在车牌识别系统中的应用

基于车牌识别原理,提出一种新的车牌识别方法.将单片射频收发芯片nRF905应用到车牌识别系统中.并采用ShockBurstTM工作模式,自动处理字头和CRC(循环冗余码校验),使用SPI接口与微控制器通信,配置方便.该系统具有识别精度高,抗干扰能力强,通信速度快,检测距离远等特点.     

Three-dimensional analysis of transient slosh within a partly-filled tank equipped with baffles

The directional dynamic analyses of partly-filled tank vehicles have been limited to quasi-static fluid motion due to computational complexities associated with dynamic fluid slosh analyses. The dynamic fluid slosh causes significantly higher magnitudes of slosh forces and moments in the transient state that cannot be characterized through quasi-static approach, which provides reasonably good estimates of the mean responses. In this study, a three-dimensional nonlinear model of a partly-filled cylindrical tank with and without baffles is developed to investigate the significance of resulting destabilizing forces and moments caused by the transient fluid slosh, and the effects of baffles. The baffles and the end caps are modeled with curved shapes. The analyses are performed under varying magnitudes of steady lateral, longitudinal and combinations of lateral and longitudinal accelerations of the tank, and two different fill volumes using the FLUENT software. The results of the study are presented in terms of mean and peak slosh forces and moments, and variations in the mass moments of inertia of the fluid cargo within a clean bore and a baffled tank, for two different fill volumes and different magnitudes of acceleration excitations. The ratios of transient responses to the mean responses, termed as amplification factors, are further described to emphasize the significance of dynamic fluid slosh on the forces and moments induced on the vehicle. The results in general suggest that the mean responses attained from dynamic fluid slosh analyses correlate well with those attained from the quasi-static analyses for a clean bore tank. The amplification ratios of the resulting forces and moments could approach as high as 2. The results clearly show that the presence of baffles helps to suppress the peak as well as mean slosh forces and moments significantly.     

基于温度传感器的三元催化转化器工作效率监控试验研究

分析了应用双温度传感器监控汽车三元催化转化器工作效率的可行性,依据所提整体转化效率概念,对汽车排气污染物转化效率进行了量化处理。进行了整车稳态工况下催化转化器出入口温度的监控试验。试验结果表明,车速与催化器出入口温差是影响催化转化器工作效率的主要因素。应用多元线性回归理论建立了文中所用催化转化器转化效率的监控模型。     

短吊杆频率法索力系数修正的研究

针对现有的弦振公式不能够真实反应短索频率与索力之间关系的问题,给出了在不同工况下计算长度的取值方法,并考虑抗弯刚度对索力的影响,提出索力计算修正系数。通过理论计算与康复南路跨线桥工程实例,表明该公式有很好的计算精度,适用于短吊杆索力的测试计算。     

人行斜跨钢箱拱桥设计与分析

介绍某城市人行钢箱斜跨拱桥的总体设计方案;建立空间有限元模型分析设计控制要点,包括索力、应力、位移、动力特性和稳定性.结果 表明,各项静动力指标均满足规范要求.介绍桥面铺装和抗浮销铰两个特色设计,可增强结构安全性、耐久性和景观性,以期为类似人行桥梁设计提供参考.