Assessment of fatigue strength of steel butt-welded joints in as-welded condition – Alternative approaches for curve fitting and mean stress effect analysis

Experimental fatigue data for butt-welded joints in as-welded condition and under constant amplitude tensile loading (secondary bending included) were analyzed using the nominal stress system and the notch stress system. Two approaches were used; a standard fitting procedure and minimization of the sum of squared perpendicular distances from a line with a fixed and free slope. In all cases, the latter method gave better agreement between the experimental and predicted fatigue life and fatigue strength. The analyses showed both with all broken specimen data included and with reduced data that the FAT225 curve, as recommended by IIW, might be too optimistic for the notch stress approach in the case of butt-welded joints in as-welded condition. It was also found that use of the local stress ratio instead of the applied stress ratio might explain many issues concerning current observations and apparent inconsistencies in reported literature.     

三维立体软件INVENTOR的应用技巧

本文主要介绍了三维立体软件INVENTOR的组成和优点,重点介绍在使用该软件过程中的设计经验、使用技巧,帮助初学者解决在使用过程中遇到的难题。     

高速动车组角焊缝应力集中的识别方法

针对高速动车组焊接构架角焊缝处应力集中无法采用名义应力法识别的问题,基于结构应力法,将角焊缝焊趾处的非线性应力分解为满足外载荷平衡的结构应力和自平衡的缺口应力,然后根据力的平衡方程得到各节点力及其力矩与线力及其线力矩间的对应关系,进而推导出结构应力的计算公式,并给出角焊缝应力集中识别流程;基于所给出的算法和识别流程,采用C/C++以及ANSYS软件提供的APDL语言开发出焊接结构应力识别专用软件WSS,对某高速动车组焊接构架上诸多角焊缝应力集中进行识别,验证了基于结构应力的角焊缝应力集中识别方法不仅能给出应力集中的具体位置,还能给出具体的应力峰值及其对应的疲劳寿命,可用于优化高速动车组焊接构架的抗疲劳设计。     

《渔港总体设计规范》修订概况

介绍《渔港总体设计规范》修订的必要性和修订概况。     

A literature review of flexible development of airport terminals

The Master Plan has long been the traditional go-to approach to airport development. It was originally conceived for a scenario of stable growth. In recent decades, however, the airport industry has undergone substantial structural changes, with the traditional Master Plan progressively revealing limitations with regard to airports coping with the market’s unpredictability. There have since been increased calls for flexibility in the approach as an alternative or as a complement to the traditional Master Plan. A flexible development plan helps to accommodate changes within terminals. This paper presents a review of the current literature on airport terminal flexibility, covering a total of 19 reference works. The works were analysed in terms of the concepts, definitions and deployment frameworks, or similar. The review reveals that research in airport terminal flexibility is still in its early stages. A consensual definition has yet to be defined and no robust framework for deploying flexibility has been defined. We propose a new definition of flexible development. Furthermore, flexibility has been studied essentially in the context of expansion. However, in certain regions where land availability is scarce, other forms of airport development may be more important. We conclude the paper with suggestions for future research areas.     

沥青混合料动态特性试验研究

文章通过采用简单性能试验机（SPT）测量AC13、AC16和AC20三种沥青混凝土在不同温度和荷载作用频率下的动态模量和相位角,分析了温度和荷载作用频率对沥青混合料动态特性的影响,并依据时-温等效原理,对沥青混合料的粘弹性性质进行了研究。     

轻型汽车制动总泵铝合金主缸的液态模锻

采用104铝加一定添加剂后液态模锻生产轻型汽车制动总泵铝合金主缸，其硬度平均值为HBl05，机加切削性能良好，尺寸精度和表面质量与采用压铸工艺生产的铝合金主缸相当；而其机械性能高于采用压铸工艺生产的铝合金主缸，一次性投资低于压铸生产工艺，对产品批量的适应范围比压铸生产宽，成本则比压铸生产低。详细介绍了液态模锻的工艺特点及液态模锻模的结构设计特点。     

基于SX5256DH434PHEV型混合动力重型环卫车的电池管理系统浅谈

在全球能源危机的情况下,随着国际碳排放出口协定的实施,绿色清洁汽车已经成为发达国家当前汽车技术的发展方向,发达国家多数把锂离子电池作为EV、HEV、PHEV的新能源。由于汽车的复杂工况和锂离子电池电化学特性,一般需要完善的电池管理系统BMS(BATTERY MANAGEMENT SYSTEM),其作用是对锂离子电池电压、电流、温度、容量、电池的SOC荷电状态计量、电池与车体的绝缘状态等多种电池参数以CAN通讯的方式与车控电脑实时进行信息交换,确保电池的能量发挥到极致,使驾驶者能够随时掌握电池的工作状态,以保证电池的安全。BMS不仅是数字化智能电池系统的中枢神经,也是新能源汽车必不可少的关键部件。     

中型客车制动系统设计开发思路及方法

随着高速公路的迅速发展和车速的提高以及车流密度的日益增大,为了保证行车安全,汽车制动系的工作可靠性显得日益重要。也只有制动性能良好、制动系工作可靠的汽车,才能充分发挥其动力性能。这里主要叙述中型客车制动系统的设计开发思路、主要制动参数的确认及校核、协调方法、试验的重要性。     

An analytical SCF solution method for joint misalignments and application in fatigue test data interpretation

In this study, we first present a general analytical method for calculating stress concentration factors in a cruciform connection containing either axial or angular misalignment between two intercostal members through an application of Castigliano's second theorem. As such, various end restraint conditions of interest in practice can be considered with ease. Such a solution method provides stress concentration factors at intersection location not only with respect to intercostal members, but also with respect to continuous members. A comprehensive set of SCF solutions, confirmed by finite element solutions, are then presented in tabular forms which can be used as supplements to the existing SCF solutions such as those given in BS 7910 and DNV-RP-C203 for performing fatigue and fracture assessment of welded connections. Some of the existing solutions are shown to be valid only under a narrower set of conditions than documented and some seem to be in significant error. As a further demonstration of the validity of the analytical approach presented in this paper, the same analytical formulation is applied for examining interaction effects between misalignments and fatigue testing conditions, resulting in significantly improved correlation of fatigue test data obtained as a part of this study.