按最高油膜压力评定轴承材料的疲劳强度

在任何给定工况下,有一系列因素影响最终选择轴承合金的种类和牌号,但首先考虑的必须是承载能力。如果轴承材料在所需的使用时间内不能承受所施加的负荷,那么轴承材料的其它特性再满意也是毫无意义的。因此习惯于把轴承材料抗疲劳性能进行分级,这对于轴承使用者和供应商都是极为重要的。 把轴承材料抗疲劳性能分级的传统方法是用最大单位负荷,即轴承经受的最大负荷被轴承投影面积（长度×直径）所除。直到不久前这仍是人们希望为某一应用场合选择合适轴承材料的唯一使用的依据。但这种方法具有很大缺陷,因为疲劳不仅与负荷,而且与所加负荷频率有关。如讲某一轴承在承受一定的单位负荷下不会破坏,这是一种不恰当的评估方法,因为没有讲到该轴承在一定的单位负荷下能承受多长时间。 美国JPl公司现已采用最高油膜压力（POFP）来评估常用轴承材料。它利用传统的安德伍试验机的试验数据,建立了最高油膜压力值和疲劳前循环次数的数学方程,找出了有关额定值,并提出了如何使用该额定值的方法。 下面介绍该公司是如何按照最高油膜压力来评定材料疲劳寿命的。     

基于热点应力的焊缝疲劳强度评定研究

为解决名义应力法在焊接结构疲劳强度评定中应用的局限性,全面介绍和分析了当前国际上研究较多的基于热点应力的焊接板结构焊缝疲劳强度评定方法。主要包括热点应力定义、组成及其类型,热点应力的外推法确定及相应的有限元建模原则,DNV推荐的热点应力S—N曲线和经典的焊接结构疲劳强度评定及寿命预测算法。在机车车辆焊接承载部件的疲劳分析中,合理应用热点应力法以补充和完善名义应力评定,对提高评定及寿命预测精度具有较为现实的实用价值。     

"天梭"号机车车轮强度研究

介绍了用ANSYS软件计算"天梭"号交流电力机车车轮强度的情况,包括车轮结构,计算模型简化,结构离散化处理,载荷处理,约束处理以及计算结果和结论。     

机车车轮与固定辙叉的弹塑性接触分析

针对大秦线重载铁路道岔固定辙叉的磨耗问题,运用有限元法求解机车车轮与12号高锰钢辙叉接触问题,分析了不同情况下车轮与辙叉的接触斑面积、接触轨迹、等效应力和轮心垂向位移的变化规律。计算结果表明：磨耗后车轮与辙叉的接触斑面积大于标准车轮,磨耗后车轮与磨耗后的辙叉能更好匹配;车轮从翼轨向心轨过渡的过程中,辙叉的等效应力由900 MPa增加到1 300 MPa,超过材料的屈服极限产生塑性变形;轮心的最大垂向位移为8 mm,使车轮过叉的平顺性能恶化。     

预热加氢反应器的安全评定

为判定由国外引进的1台旧反应器是否能继续使用,现场对共进行了拆装、清理、初步检验和全面检验,对发现的超标缺陷进行了安全评定评定结果表明,此反应器虽然存在较严重的缺陷,但都在安全限度内,通过设计单位的选用,可以在一定条件下继续使用.     

基于名义应力的焊接结构疲劳强度评定方法研究

分析和研究了我国钢结构设计规范、英国钢结构疲劳设计和评定规程以及国际焊接学会焊接接头及构件疲劳设计标准中基于名义应力的焊接结构疲劳强度评定方法。各规范或标准均使用经典的疲劳理论作为疲劳计算依据,评定方法简单易用,且提供的疲劳强度数据以实验室疲劳试验为基础,应用于工程实际问题具有较高的可靠性。合理应用这些数据和方法于机车车辆焊接承载结构的疲劳强度分析,对提高机车车辆的安全可靠性具有十分现实的意义。     

牡丹江第二发电厂除氧器安全评定的探讨

本文针对牡丹江第二发电厂，１除氧器质量问题的处理意见进行限详细地论述。文章引用了历年来颁布的压力容器标准，时间一台设备进行了安全评定，得出了不同的结论。究竟应该执行哪个标准，本言语提出了看法，并对“在用压力容器检验规程”中的有关条款提出了不同的见解，供探讨。     

液化石油气球罐的安全评定

通过对液化石油气球罐的定期检验,运用软件对球罐进行安全评定。结果表明,缺陷球罐通过基于常规评定方法的安全性评价计算,其在正常工况下运行是安全的,不会发生失效。软件分析在一定程度上可以替代常规人工评定,缺陷评估效率得到很大提高。     

基于静力子结构技术对轮轴接触下车轮的强度分析

利用有限元分析中的静力子结构技术,在考虑轮轴过盈配合接触非线性情况下,利用有限计算资源,应用有限元方法快速完成车轮的强度分析。计算结果表明,采用此方法可以更加真实而准确地反映车轮在多载荷工况下的应力分布。     

端齿盘在高速转向架空心轴传动中的应用

介绍了端齿联接机构在六轴交流高速转向架空心轴传动中的应用情况,对其主要参数选择原则、最小预紧力的确定、齿形强度计算和齿副接触应力等进行了阐述。指出梯形收缩齿形是端齿盘的首选齿形。建立了端齿盘的三维有限元模型。通过对接触应力的变化曲线进行分析,得出内齿尖处的接触应力最大的结论。     

An evaluation of multiaxial fatigue life assessment methods for engineering components

This article deals with the problem of multiaxial fatigue life assessment of engineering components. General aspects of the critical plane damage models are discussed first. A computer-based procedure for multiaxial fatigue life assessment incorporating critical plane damage models, suitable for use in design evaluations of engineering components based on finite element analysis results, is presented and applied to correlate results from tests conducted on SAE 1045 steel notched shaft specimens. From experimental data correlations, it is found that the second variant of the critical plane models (in which critical planes are defined as the planes experiencing the maximum damage) provides better life estimates than the first variant (in which critical planes are defined as the planes experiencing the maximum range of strain) or the conventional local strain based life prediction method, even for simple and short loading histories made up of repeating cycles.     

Lightening structure optimization on turbine wheel of vehicular turbocharger

Based on basic principle of optimization design, structure optimization of turbine is conducted using optimization module of ANSYS and APDL in order to get the minimum turbine weight. Meanwhile, the original blade profile and flow passage are maintained, and the structural strength of the turbine are guaranteed. Considering assembly technique and cast requirement, the structure of the modified turbine is determined which can save 6.91 percent of the material compared with the original one. The modified turbine not only saved material, but also gained better effect of mass distribution between the turbine and the compressor impeller. The result can provide useful reference to engineering application of turbocharger. __________ Translated from Chinese Internal Combustion Engine Engineering, 2008, 29(1): 48–51 [译自: 内燃机工程]     

曲轴强度疲劳计算的研究及应用

阐述了关于曲轴强度计算原理及方法,提出了多体动力学、有限元及疲劳软件联合计算的方法解决关于曲轴疲劳的计算方法,并运用该方法对某D系列柴油机的曲轴疲劳进行计算。     

AK‐DA: An efficient method for the fatigue assessment of wind turbine structures

Lifetime damage estimation is a complex and demanding task that needs to be performed during the design of offshore wind turbine structures. A general damage analysis framework is proposed by the certification bodies. Therein the total lifetime of the structure is considered as a series of elementary situations combining structural and environmental states. For a given structural state, the loading environment is described using statistical parameters such as the wind mean speed at hub height or the peak spectral period of the sea. An estimation of the structural response is to be computed for each of the environmental combinations of parameters, therefore leading to tens of thousands simulations. The cost of a single simulation makes this process often unfeasible for engineers who are usually forced to reduce the number of simulations considering industrial feedback with risks of potential lack of representativity of results. This paper aims at presenting a novel method for the reduction of the simulation costs relative to the long‐term damage estimation (relative to a design load case) and based on the so‐called adaptive Kriging approach. From on a reduced set of observations (multiphysics simulator runs), a Kriging metamodel is here used to approximate the damage model response for all the nonsimulated sets of environmental parameters. The latter are subsequently used to assess the long‐term damage as presented in the standards. The statistical measure of the metamodel error of prediction is used into an iterative structure in order to progressively enrich the design of experiments with informative sets of environmental parameters. This allows us minimizing the global uncertainty of the approximation. The proposed algorithm, hereafter called the AK‐DA for “Adaptive Kriging Damage Assessment,” is illustrated with two industrial cases of fatigue analyses for the NREL 5MW reference monopile structure and its direct application     

基于强度折减的岩质边坡失稳判据的探讨

以锦屏水电站左岸某标段边坡为例,基于有限元强度折减法的基本原理和破坏准则,提出了综合特征点位移增量与折减系数增量的比值关系曲线与迭代次数突变准则编制有限元程序计算边坡的安全系数。计算结果表明,两种失稳判据较吻合,误差仅为1.3%,位移突变与收敛合理,该判据正确、适用。     

高速机车车辆车轴的疲劳设计

从提高高速机车车辆车轴的疲劳寿命出发,系统介绍了国外主要高速动车车轴的材质选择、强度计算、结构特点、表面处理、维修周期、检修内容以及超声波探伤技术的改进等问题,并通过对其结构参数、疲劳极限应力、表层残余应力及维修规程的分析,说明了这些车轴之所以具有高疲劳可靠性的原理。     

车轮与试验台滚轮对中方案研究

车轮与滚轮的对中是铁道车辆滚动试验台进行试验的前提。研究了两种测量机构方案,建立了对中的测量仪器模型,对两种测量方案进行了误差分析和对比。