共查询到19条相似文献,搜索用时 125 毫秒
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单梁起重机和架空单轨的工字钢尺寸,一般由跑车的轮压在翼缘上造成的局部高弯曲应力,或简称翼缘弯曲应力来决定的,(图1)。这应力在轮压作用点范围內导致工字钢的应力显著超过由法向靜力矩和横向力(即工字钢弯曲)所引起的应力。 相似文献
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以工字钢作为电动葫芦和电动单梁悬挂起重机的运行轨道时,除整体承受弯曲以外,在轮压作用区域,车轮还对工字钢的下翼缘产生局部的弯曲和挤压作用。过去以普通工字钢(GB706-65)作为原TV型电动葫芦的运行轨道,没有出现过材料的破坏,因而没有引起人们的重视。近年来,冶金部推广使用轻型工字钢,它的翼缘较薄,同时电动葫芦又作了更新 相似文献
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局部弯曲应力的计算是下翼缘受载的工字钢梁强度设计的重要内容。首先介绍了现有的工字钢下翼缘局部弯曲应力的计算方法,分析了其中存在的问题。然后构建了工字钢30a的精细三维实体有限元模型,设计了两种计算工况,并通过这两种工况的计算结果获取了较为精确的局部弯曲应力值。接着对局部弯曲应力的影响范围和分布特点进行了分析,并与现有方法的计算结果进行了比较,提出了"按照等厚板模型简化下翼缘是不合理的,基于该原则的计算结果也不够准确"的结论。最后给出了若干意见,建议在现有阶段,局部弯曲应力的计算宜直接采用三维有限元技术进行。 相似文献
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针对铝合金型材难焊、怕焊的特点,设计了一种用于电动客车铝合金骨架的榫卯连接节点,对铝合金型材梁、榫卯节点及加强榫卯节点三种结构开展了三点弯曲性能试验,研究比较了三种结构的破坏模式、力学性能和应变分布。研究结果表明,型材梁破坏模式主要是腹板屈曲变形及下翼缘受拉断裂,榫卯节点及加强榫卯节点能够减少单根卯梁腹板受力过程中的屈曲变形,两者的失效主要表现为卯梁下翼缘处焊缝开裂。在三种样件中,加强榫卯节点峰值力最高,型材梁弯曲刚度、吸能效果均优于其它两种样件。相同弯曲力下,榫卯节点卯梁腹板处应变高于型材梁,节点加强后,卯梁腹板应变有所减小,翼缘处应变增大。 相似文献
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为准确计算和分析波形钢腹板连续箱梁桥的弯曲振动频率,首先,运用能量变分原理和Hamilton原理,推导出波形钢腹板简支箱梁桥弯曲振动频率的计算公式;然后,在简支箱梁桥频率计算公式的基础上,根据连续梁自由振动的三弯矩方程,得到任意等跨等截面波形钢腹板连续箱梁桥弯曲振动频率的计算公式,该公式的正确性得到已建实桥频率实测值和Ansys三维有限元计算值的验证;最后,对波形钢腹板连续箱梁桥弯曲振动频率的影响参数进行了分析。研究结果表明,波形钢腹板剪切效应对波形钢腹板连续箱梁桥弯曲振动频率的影响较大,而其余参数对该桥型弯曲振动频率的影响较小,在实际工程中为了计算的简便性,可以忽略这些因素的影响。研究结论可为同类型桥梁的设计提供参考。 相似文献
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Huawen Shen Yuli Liu Haiyan Qi He Yang Shuhui Zhou 《The International Journal of Advanced Manufacturing Technology》2013,68(1-4):651-662
The significant cross-sectional distortion is one of the major problems in the bending of thin-walled rectangular waveguide tube. The cross-sectional distortion, which contains the flange distortion and the web distortion, depends on the stress components distribution. In this paper, the cross-sectional distortion characteristics are investigated using a three-dimensional finite element (FE) model. Results show that: the maximum flange distortion locates at the symmetric line; meanwhile, the maximum web distortion locates at the extrados ridge of the tube. The deformation zone of the tube can be divided into three sub-zones considering the loads and deformation, viz., the clamp die affect zone, the middle zone, and the mandrel/cores affect zone. Then the underlying relations between the cross-sectional distortion and the stress components are obtained. It is found that the flange distortion has a close relation with the circumferential stress. At the same time, the web distortion is relevant to both the tangential and the circumferential stress. The above relations are verified by FE models with different cores number. Moreover, some guidelines are introduced to help reduce the cross-sectional distortion. 相似文献
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这里提出了桥式起重机的箱型主梁的新型波形腹板结构的设想,并在充分比较和论证的基础上提出了以正弦曲线波形作为腹板的波形。利用大型有限元软件ANSYS对新型腹板和原来的平直腹板进行了综合比较分析,等效应力比原来腹板减少50%左右,说明波形腹板梁的受力情况更好。 相似文献
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对高压自紧式法兰密封结构进行研究,推导自紧式法兰密封比压和螺栓载荷的计算公式,并通过有限元方法进行了验证。结果表明:密封比压与内压呈一阶线性递增的关系:密封面越窄密封比压随内压递增速度越快,法兰端面与T形垫片支撑面间隙越大则初始密封比压越大。对某自紧式法兰进行结构以及热-结构耦合分析,研究内压、温度、弯矩工况的影响。结果表明:升温对高压和低压2种工况的密封性能影响不同,低压下升温使密封比压增大,高压下升温则会使密封比压有所减小;高压自紧式法兰密封受压侧垫片密封面上应力随弯矩增大先减小,但当弯矩增大到一定值后,该应力随着弯矩的增大而增大。 相似文献
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Finite element analysis of the residual stresses in T-joint fillet welds made of similar and dissimilar steels 总被引:2,自引:1,他引:1
Kyong-Ho Chang Chin-Hyung Lee 《The International Journal of Advanced Manufacturing Technology》2009,41(3-4):250-258
In this paper, weld residual stress analyses are performed for T-joint fillet welds made of similar and dissimilar steels. Three-dimensional uncoupled thermo-mechanical finite element model which can accurately capture residual stresses in a weld piece is developed in order to predict the residual stress states in the fillet-welded T-joint. Results show that the maximum longitudinal residual stresses near the weld toes of the similar steel welds increase with increasing yield stress of the steel welded. For the dissimilar steel welds, the overall trend, shape and magnitude of the residual stress profiles in flange and web are similar to those of the corresponding similar steel welds despite the slight difference between the residual stresses in parts at which the flange and web come in contact with each other. 相似文献
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In this part, analytical models to predict the deflection of cross-sectional members such as flanges and webs are developed. The models are based on the deformation theory of plasticity along with the energy method, using appropriate shape functions capable of including the restraining effect of adjacent members. The present method provides explicit solutions of cross-sectional deformations prior to buckling, onset of buckling, as well as post-buckling deformations at different stages of bending. The predictions show that the suck-in of the tensile flange is closely related to geometry parameters, particularly the flange width. Plastic anisotropy appears to be the most significant material parameter. The width-to-thickness ratio tends to be the governing parameter with respect to buckling of the inner (compressive) flange. Also, the strain hardening of the material has a major effect on onset of buckling as well as post buckling deformations. Upon continued bending after buckling, the wavy deformation of the inner flange develops more rapidly than the more uniform deformation of the outer (tensile) flange. For relatively compact sections, however, the deformation mode of the compressive flange resembles that of the tensile flange without any typical buckling waves. There are also obvious interactions between deformations of different members. Comparing the theoretical predictions with the experimental results presented in Part I, a reasonably good agreement was found. 相似文献
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三明治波纹板采用轻质化和薄壁化的结构设计方法,可以作为承载和吸能结构应用于汽车底盘前纵梁、车身Y字梁等,而现有文献缺少针对胶层厚度对波纹板性能影响的研究。通过制备胶接波纹板并开展三点弯曲工况准静态加载失效试验,分析了不同胶层厚度对三明治波纹板整体承载和吸能特性的影响规律。试验发现,不同胶层厚度下铝合金胶接波纹板结构承载能力和破坏样貌存在差异,相比于0.5 mm和1.0 mm,0.2 mm胶层厚度的三明治结构的各项力学性能和稳定性较好。随后建立胶接波纹板三点弯曲加载有限元模型,实现了对波纹板整体加载变形过程和胶层损伤的模拟,通过与试验结果对比验证了有限元建模方法的有效性,为轻质金属胶接波纹板结构设计和性能评价提供可靠方法。 相似文献
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法兰环切口对连接力学行为的影响分析 总被引:1,自引:0,他引:1
按工程简化方法设计的法兰连接结构偏于保守,不能满足结构轻量化的设计要求.根据受载时法兰环中应力分布不均匀的情况,可以通过在法兰环上预制切口提高结构效率,为研究在法兰环上预制切口对连接力学行为的影响,采用三维非线性有限元法,对三种带切口和无切口法兰进行力学分析和讨论.研究结果表明,预制切口对连接力学行为有影响;预制切口后,局部连接刚度改变,法兰弯曲和扭转变形增大,连接面张口间隙和弯曲应力均增大,切口体积是影响上述变化的主要因素;预制切口对接触面应力分布有影响,切口能够改善接触应力的均匀化程度. 相似文献