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对摩托车车架焊接变形的研究 总被引:1,自引:0,他引:1
摩托车车架大多采用复杂管和板式焊接结构,车架焊接后往往会出现焊接变形、内部产生焊接应力等,不但直接影响整车装配及整车性能,还会降低车架结构的承载能力,降低焊接接头和车架的疲劳强度而引发事故。如何保证摩托车车架的结构尺寸、形状精度及强度是车架生产中最大的问题,尤其是在大排量摩托车开发设计中尤为重要。只有对焊接进行全过程控制,采取有效的设计和工艺措施控制焊接变形,并对超出公差要求的焊接变形进行矫正,才能达到和保证车架尺寸精度和装配要求。 相似文献
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弯车架是指降低车身地板高度,与前后桥在运动极限状态不相碰的车架。弯车架分为厚板前弯车架、厚板槽型后弯车架、盒型交叉焊接弯车架、盒型局部冲压弯车架及槽型焊接弯车架等几种典型结构。厚板焊接槽型弯车架保证了整体式槽型车架的优点,避开了对大型压床及大型模具的需要。 相似文献
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分析客车底盘车架焊接结构,确定使客车底盘车架中段、前段、后段和行李舱骨架的变形量小的焊接工艺,使得整个底盘车架三段部分的焊接质量、形位精度满足设计和使用要求。 相似文献
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针对常用后倾式自卸车副车架关键部件纵梁及副车架总成焊后变形进行分析,通过采用正确的组焊工装、并对焊接方法的选择、焊接顺序和焊接规范等一系列工艺措施的优化设计,有效地解决了副车架总成焊接变形的问题。对生产现场控制副车架焊接变形工艺措施的制定有重要的指导意义。 相似文献
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摩托车车架的焊接变形及减小变形的措施 总被引:2,自引:1,他引:1
车架在制造过程中,焊接变形不可避免,只能在设计和工艺上采取有效措施控制焊接变形,并对超出公差要求的焊接变形进行矫正,才能达到车架强度、使用性能及经济性能的要求。 相似文献
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盒式梁车架总成主要靠焊接连接,焊缝复杂,弧焊后变形量大,影响悬架、转向、发动机等系统的后续装配精度。为了保证车架的焊接质量,文章夹具结构、焊接顺序和焊接设备等方面提出对盒式梁汽车车架的焊接变形及质量控制方法。 相似文献
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矿用自卸车是露天矿开采不可或缺的运输设备,车架为整个矿车的基础,在矿用自卸车行业,车架有两个基本技术路线,一个为刚性结构焊接车架,另一个是柔性结构铆接车架,两种结构车架均有较长的发展历史和成熟的技术。本文着重分析了焊接车架与铆接车架的疲劳强度和材料,为车架结构形式选择指明了方向,以此制造更优异的矿车车架。 相似文献
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Fatigue design approach for the spot-welded T-type member using a simulated single spot-welded joint
In order to develop a fatigue design method for actual railroad car and commercial vehicle body structures using the fatigue
data of simulated single spot-welded lap joints, we first analyzed the stress distribution and evaluated fatigue strength
of spot-welded T-type members that are the components of actual railroad car and commercial vehicle body structures. Next,
fatigue design approach of these members using the fatigue data of single spot-welded lap joints was investigated. From our
results, we found that, even though there was a quantitative difference of fatigue strength between the single spot-welded
joint and the actual members over the same number of fatigue cycles, through the use of appropriate correction, the fatigue
design criterion of actual spot-welded members, such as those used in railroad car and commercial vehicle body, can be predicted
using the fatigue strength of single spot-welded joint. 相似文献
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正交异性桥面板U肋-面板焊接接头为疲劳裂纹多发部位,为了提高U肋-面板焊接接头疲劳性能,分析目前规范中对该构造细节的疲劳设计要求以及疲劳问题依然存在的原因,在目前主要采用部分熔透焊形式的背景下,考虑引入全熔透焊接以期达到提高疲劳性能的目的。研究围绕一种全新的U肋-面板全熔透焊接接头的疲劳性能分别开展构造细节和节段足尺模型试验研究。试验结果表明:全熔透疲劳裂纹都是始于U肋内侧焊趾处,沿着U肋腹板厚度方向发展,部分熔透焊裂纹主要始于未熔透焊缝的焊根部位,沿焊喉方向发展,直至贯通整个焊喉,且在同样加载条件下,全熔透焊裂纹产生的加载次数明显高于部分熔透焊;全熔透焊的热点应力试验测试值与理论计算值基本一致,U肋焊趾部位应力集中明显,内侧受拉外侧受压,解释了疲劳裂纹起始点为U肋焊趾内侧;经回归计算得到热点应力疲劳强度为263.8 MPa;将足尺节段疲劳试验加载幅度对应的加载次数换算为公路桥梁规范单车轮轮载60 kN所对应的加载次数,2个试件加载次数都超过1.2亿次,且U肋-面板全熔透焊接接头依然没有疲劳裂纹产生,表明U肋-面板全熔透焊接接头具备优良的抗疲劳性能。 相似文献
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S. R. Sin S. M. Yang H. S. Yu C. W. Kim H. Y. Kang 《International Journal of Automotive Technology》2008,9(1):81-86
The welding quality of spot weldment is an important factor that significantly affects the strength, stiffness, safety, and
other performance characteristics of vehicles. Therefore, quality control and fatigue life evaluation of spot weldment are
necessary processes. This paper presents a method for determining the fatigue life of multi-lap spot weldment of a high strength
steel sheet. In this method, the fatigue life is estimated using the lethargy coefficient, which is the total defect coefficient
according to rupture stress and time obtained by the quasi static tensile-shear test. The DC potential drop method was used
to check initiation and propagation of cracks in addition to the test. Also, in this study, we modified the lethargy coefficient
by using the welding current. Furthermore, we define a specific lapping constant, which is a characteristic constant of 2
or 3 lap weldments. The fatigue life obtained by the fatigue estimate equation, which contains a specific lapping constant
was compared and verified with an experimental value. Finally we analyzed the relation of lap number, welding current and
fatigue life. This method can save processing time and cost for predicting the life cycle of a structure. 相似文献
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设置高疲劳抗力构造细节是提升钢桥面板疲劳寿命的有效途径之一,以一种钢桥面板-肋双面焊构造细节为研究对象,基于线弹性断裂力学原理,利用ABAQUS有限元软件建立了该细节疲劳裂纹扩展子模型,研究了疲劳加载工况下各裂纹萌生点处初始裂纹扩展能力.同时通过应力强度因子幅值对比分析,进一步确定了该钢桥面板-肋双面焊构造细节主导疲劳失效模式. 相似文献
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This paper presents a method to assess of fatigue strength for resistance spot welded joints, which incorporates welding residual stress effects. To achieve this, first, a non-linear finite element analysis (FEA) was performed to simulate the spot-welding process. To validate the FEA results, the numerically calculated welding residual stresses of spot welds were then compared with experimental results measured by X-ray diffraction method. The residual stress distributions showed good agreement between calculations and experiments. To evaluate the effects of welding residual stress on the fatigue design criterion of resistance spot welded joints subjected to cross-tension load, the stress amplitude (σa-res) taking into account welding residual stress at a spot weld was proposed based on a modified Goodman equation incorporating the residual stress effect. Using the stress amplitude σa-res at the nugget edge of a spot weld, the ΔP ? Nf relations obtained as the fatigue test results for spot welded joints were systematically rearranged to the σa-res ? Nf relation. It was found that the proposed stress amplitude (σa-res) provides more reasonable and accurate fatigue design criterion of spot welded joints subjected to cross-tension load. 相似文献
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为研究超大跨径斜拉桥钢桥面板的疲劳损伤问题,本文以某斜拉桥为工程背景,对实桥进行了现场疲劳损伤监测与分析,并基于断裂力学的三维裂纹扩展模型,对钢箱梁顶板-U肋和横隔板-U肋等焊接细节进行了数值仿真与研究。结果表明:实桥顶板-U肋焊缝细节高应力幅(大于10MPa)循环次数与疲劳损伤度明显低于横隔板-U肋细节,横隔板-U肋焊缝最大应力幅达到75~90MPa,顶板-U肋焊缝最大应力幅为15~30MPa,横隔板-U肋焊缝细节处裂纹数量远大于顶板-U肋焊缝细节处裂纹数量;顶板-U肋焊缝裂纹在扩展过程中基本保持平面,裂纹扩展有先沿焊缝方向纵向扩展,再向深度方向扩展的趋势;横隔板-U肋焊缝焊趾处裂纹先沿初始裂纹深度方向在横隔板扩展,再向横隔板厚度方向扩展,焊趾处裂纹先向U肋厚度方向扩展,后沿初始裂纹长度方向顺桥向扩展;在初始裂纹尺寸与荷载条件相同的情况下,顶板-U肋焊缝焊趾处裂纹扩展速度大于焊根处裂纹扩展速度,横隔板-U肋焊缝焊趾处裂纹扩展速率大于横隔板焊趾处裂纹扩展速率。 相似文献
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以某大跨径斜拉桥为研究背景,基于钢箱梁的定期检测结果,研究了该斜拉桥的钢结构疲劳性能。在疲劳开裂较严重的顶板与U肋焊接细节、关键受力部位的底板与U肋焊接细节、索梁锚固区焊接细节布置传感器,测试各主要焊接细节的疲劳应力历程,基于雨流计数法获得疲劳应力谱。分析结果表明:苏通大桥目前的交通流量远大于2010年前的交通流量;钢箱梁底板与U肋焊接细节、索梁锚固区锚固板与外腹板焊接细节的疲劳寿命评估结果大于设计使用年限;若不计焊接初始缺陷与焊接残余应力,顶板与U肋焊接细节不会过早地发生疲劳破坏。 相似文献
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正交异性钢桥面板纵肋构造细节疲劳危害严重,修复困难,传统单面焊构造疲劳抗力不足是导致该部位疲劳开裂频发的主要原因。采用双面焊构造可望显著提高该构造细节的疲劳抗力,而初始焊接缺陷是该类构造细节疲劳抗力的关键影响因素。以双面焊构造为研究对象,基于线弹性断裂力学理论,建立多裂纹扩展模拟方法,通过多裂纹扩展试验验证该方法的可行性;在此基础上,对焊根处存在单一和多个初始缺陷条件下构造细节疲劳裂纹扩展特性进行研究。结果表明:外侧焊根单裂纹、内侧焊根单裂纹与焊根多裂纹扩展模式均为Ⅰ型开裂主导的Ⅰ-Ⅱ-Ⅲ型复合裂纹扩展模式;多裂纹扩展特性并不显著,多裂纹在扩展初期由于临近裂纹等效应力强度因子幅值的迅速降低而转变为单一裂纹,此后其扩展规律与外侧焊根单裂纹扩展规律基本一致;3种裂纹在扩展初期裂纹形状比变化规律存在差异,但随着扩展深度的增加,等效应力强度因子幅值下降段变化规律基本一致,裂纹扩展达到一定深度后均呈扁平状且随扩展深度增加扁平状趋势更加显著;外侧焊根处的单一缺陷是控制钢桥面板纵肋双面焊构造疲劳抗力的主要缺陷,制造时应采取有效措施避免这类缺陷。 相似文献