Fatigue design for plug/ring type gas welded joints of sts301l including welding residual stresses

This paper presents a fatigue design method for plug and ring type gas welded joints, which incorporates welding residual stress effects. A non-linear finite element analysis (FEA) was first performed to simulate the gas welding process. The numerically predicted residual stresses of the gas welds were then compared to experimental results measured using a hole drilling method. In order to evaluate the fatigue strength of the plug and ring type gas welded joints, a stress amplitude (σ _a ) _R taling the welding residual stress of the gas weld into account was introduced and is based on a modified Goodman equation incorporating the effect of the residual stress. Using the stress amplitude (σ _a ) _R , the ΔP-N _f relations obtained from fatigue tests for plug and ring type gas welded joints having various dimensions and shapes were systematically rearranged into (σ _a ) _R -N _f relations. It was found that the proposed stress amplitude (σ _a ) _R could provide a systematic and reasonable fatigue design criterion for the plug and ring type gas welded joints.     

Optimized design for a MacPherson strut suspension with side load springs

Undesired lateral force inevitably exists in a MacPherson suspension system, which is liable to damper rod’s side wear and promotes the damper’s inner friction decreasing the ride performance from the suspension system. Substituting a new side load spring with curved centerline for the conventional coil spring has been proven able to solve these problems and Multi-body Dynamics combining with Finite Elements Analysis may be an efficient method in optimizing its design. Therefore, taking a passenger car as example, a detailed multi-body dynamics model for the suspension system is built to simulate forces exerted on the damper and the minimization of its lateral component is selected as the design target for the spring. When the structure optimization of the side load spring is performed using FEA software ANSYS, its vertical and lateral elastic characteristics, supported by test data, are analyzed. After importing FEA results back to the suspension system, the dynamics simulation can be performed to validate the optimization result.     

Bolster spring fault detection strategy for heavy haul wagons

An on-board health monitoring system is proposed for heavy haul wagons in this paper including a signal-based fault detection and isolation (FDI) method and an on-line fault diagnose strategy. Such a system, to be feasible on freight wagons, must be sufficiently cheap and robust, hence the design assumes the constraint of using only two accelerometers mounted on the front left and right rear part of each carbody in a heavy haul train. This paper focuses on the detection of bolster spring fault conditions. The problem is made more complex by the modes of failure which might be expected in bolster spring nests. Types of spring failure are firstly identified and discussed covering situations of broken (shortening springs) and softening (individual spring loss from a nest or cross-section loss through corrosion). The effects of these faults and their detectability were investigated using simulations on straight and curved track and using a fully detailed model of a typical 40?t axle-load heavy haul wagon. The simulation results were then examined and compared using cross-correlation analysis and an FDI system was proposed. The FDI system introduced five possible fault indicators. Initial results indicated that it was possible to detect changes in bolster stiffness of ±25%. An on-line fault diagnoses strategy is proposed for bolster spring faults which only requires data from wagon monitoring during travel around sharp curves to detect and the occurrence of confirm faults. The functionality envisaged needs only a ‘once per trip’ monitoring site, such as a sharper curve, and is aimed at condition monitoring rather than the provision of alarms or comprehensive monitoring of all events.     

二系螺旋弹簧刚度计算

采用有限元计算方法,对机车车辆二系螺旋弹簧的刚度进行计算。结果表明,弹簧在横向载荷作用下,由于上端移动,垂向载荷的作用位置随之发生变化,在弹簧两端切口的影响下,弹簧的受力状态发生变化,垂向刚度随载荷的变化而变化比较明显,横向刚度与所施加的横向载荷方向有关。     

地铁车辆的车体调簧工艺研究

主要介绍了地铁车辆车体部分的调簧工艺,该工艺保证车体重量在轮载上的均匀分布,同时保证车体和转向架的互换性,为提高地铁车辆质量提供一个有效措施。     

电力机车转向架弹簧制造工艺比较分析

通过对几种常见的电力机车转向架弹簧制造工艺进行比较分析,结合国内制造情况,提出了电力机车转向架弹簧制造工艺改进方案。     

重型卡车钢板弹簧骑马螺栓拧紧力矩衰减探讨

分别对骑马螺栓在钢板弹簧正反向安装状态下的受力状态进行了研究,通过对骑马螺栓在不同状态下的受力分析对比,得出造成骑马螺栓拧紧力矩衰减的根本原因,最后通过对骑马螺栓拧紧力矩衰减的机理分析,提出了有效减缓骑马螺栓力矩衰减的措施。     

基于系统工程的春运摩托车返乡潮现象的交通事故机理分析

春运摩托车返乡潮是我国近几年出现的独特新现象,其交通事故频发的状况引起了社会的高度关注。针对此问题,采用交通系统工程的分析方法,构建了摩托车交通安全系统的基本要素及其相互关系模型图,以有关的文献报道和调查资料为基础,从人、车、路、环境和管理等方面归纳分析了恶劣天气型、疲劳行车型、黑夜行车型、路况不熟型、路况不良型及骑车技能不佳型等6种类型摩托车交通事故的机理。最后分别给公路管理部门、交警部门及政府提出了对策建议。     

连续箱梁桥内力增大系数的计算模型

提出了具有一对弹簧支承的计算模型,用来计算连续箱梁桥的内力增大系数.用本模型所得到的一个算例的分析结果与按传统方法的分析值吻合甚好,并且它比后者在计算过程上得到了一定程度的简化.     

刚柔耦合建模技术在横置钢板弹簧独立悬架中的应用

钢板弹簧是汽车悬架系统常用的弹性元件．利用机械系统动力学软件ADAMs建立刚柔耦合的横置钢板弹簧独立悬架系统的仿真模型，并进行了仿真分析和试验研究．悬架仿真分析的结果与试验数据基本吻合，说明刚柔耦合建模技术在横置钢板弹簧独立悬架中的应用是成功的。