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柴油机缸体主轴承壁结构安全性分新 总被引:1,自引:0,他引:1
本文分析在螺栓预紧力、最大爆发压力载荷作用下,柴油机主轴承壁的应力应变情况.通过有限元前处理MasterFEM划分有限元网格,导入有限元分析软件ANSYS计算柴油机主轴承壁的应力应变.对比AVL公司的计算结果,本柴油机的主轴承壁的结构是安全可靠的. 相似文献
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针对一款2.7 L高增压柴油机,采用有限元方法计算了机体的结构强度,分析了热载荷与机械载荷对机体主轴承壁区域的应变分布影响。设计了发动机台架实验,测取机体主轴承壁面的温度与动态应变,对计算结果进行验证并分析了产生误差的原因。研究结果表明:机体主轴承壁的工作应力由热应力与动载应力两部分组成,在额定工况下,热应力占主导地位。通过对比模拟与实验结果可以发现,基于第3类热载荷边界条件计算得到的壁面温度精度较高,但是该方法精度强烈依赖输入的换热系数精度。基于有限元方法获得的应变模拟值表现出良好的跟随性。有限元方法对最大动载荷模拟精度较高。最大工作应变计算误差主要来自于最大热应力的计算误差。计算模型的拓扑网格结构、测点当地材料属性与换热条件是造成计算误差的3个主要因素。 相似文献
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以船用低速柴油机主轴承轴瓦为研究对象,针对轴瓦在安装过程中受到的螺栓预紧力作用和工作过程中受到油膜压力作用进行仿真分析。应用有限差分法求解轴瓦油膜压力分布,利用有限元软件计算轴瓦安装时在预紧力作用下产生的形变量,模拟分析轴瓦在考虑和不考虑预紧力作用时,在油膜压力作用下的应力应变分布情况。结果表明:由于受到预紧力的作用,主轴承轴瓦两端面出现形变量的最大值;轴瓦在安装过程中受到预紧力作用而产生的应力应变较大,影响了工作过程中油膜压力对轴瓦的作用,因此在分析轴瓦工作时的应力应变情况时,不能忽略螺栓预紧力的影响;预紧力不仅影响轴瓦应力应变值的大小,同时改变应力应变值的变化规律。 相似文献
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本文内容包括主轴承盖三维实体造型、三维网格划分、载荷和约束处理,并以 S L4105 柴油机悬挂式主轴承盖为例,应用 S A P93 软件进行了三维有限元分析,计算精度较高。 相似文献
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为了分析轴承压装过程中不同轴承座壁厚对压装力、轴承座内部应力和应变的影响,为轴承座设计和改进提供参考依据,采用三维软件Solidworks建立轴承与轴承座过盈配合模型图,通过ANSYS有限元软件对轴承压装进行分析,得出不同轴承座壁厚情况下的压装力-时间曲线关系图.仿真结果表明,轴承外圈与轴承座刚接触时,轴承外圈对轴承座有冲击作用,压装力随时间先增加后波动,最后近似于平滑曲线变化;轴承座壁越厚,应力、应变越小.在设计轴承座时,应选择塑性较好的材料;在满足刚度的同时,轴承座壁厚尽可能小一些. 相似文献
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某型号铁路轴承试验机接连发生3根主轴断裂事故,为了分析主轴断裂原因,建立了主轴有限元分析模型,计算出了主轴静应力分布情况.在有限元静力学分析基础上,根据给定的载荷,用“轴不动、载荷旋转”来模拟实际的“轴旋转、载荷不变”情况,采用专业疲劳分析软件Fe- Safe计算了主轴的疲劳强度.计算结果表明,主轴疲劳强度安全系数小于... 相似文献
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V. I. Kucheryavyi S. N. Mil’kov 《Journal of Machinery Manufacture and Reliability》2008,37(6):618-622
Within the framework of the theory of random values, a formula for the index of the static model of the strength reliability of a beam section of a pipeline is obtained (the probability of indestruction) in the case where the physical and mechanical characteristics of pipes, the load in the bearing structures, the internal gas pressure, the pipe wall temperature difference, the pipe diameter, and the pipe wall thickness are normally distributed. Optimal characteristics of pipeline reliability are obtained at the design stage such that the failure-free operation of the gas pipeline section on equidistant bearing structures is ensured for the service life limit. 相似文献
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车下设备承载结构疲劳试验载荷谱编制方法* 总被引:6,自引:0,他引:6
提出多载荷时间历程的外推方法,给出车下设备承载结构疲劳试验载荷谱编制方法。基于载荷时间历程的雨流计数矩阵,利用二维核密度估计方法(Kernel density estimation, KDE),提出在多载荷时间历程输入条件下的外推方法;应用平均应力修正公式、累积损伤理论和等效损伤准则,根据外推载荷数据,给出疲劳试验程序谱的编制方法;结合动车组车下设备线路测试数据对外推方法进行验证,编制了车下设备承载结构疲劳试验程序谱,并分别使用疲劳试验程序谱和振动测试数据对承载结构进行疲劳强度计算。数据外推结果表明:多载荷时间历程外推方法计算的损伤与实际载荷损伤误差为3.6%,大的扩展倍数下KDE可以给出低周、大幅值载荷;疲劳强度计算结果表明:由于KDE外推产生了大幅值载荷,疲劳试验程序谱计算的损伤比振动测试数据计算的损伤增加了43.8%,所以,在进行疲劳试验载荷谱编制时,需要计算可能出现的大幅值载荷。此研究为其他结构程序载荷谱的编制提供借鉴案例。 相似文献
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Reynolds lubrication theory assumes that there is no wall slip on the interfaces between the solids and lubricant. During recent years, however, it is found that wall slip often happens. The present paper analyzes the wall slip occurring in a hydrodynamic lubrication journal bearing. If the two surfaces have the same adhesion property wall slip always decreases the oil film load support capacity. If there is wall slip over all of the lubricated surfaces, the hydrodynamic effect of the journal bearing vanishes, and no load support exists. If the two lubricated surfaces have different adhesion properties, the wall slip effect is more complex and may cause the journal bearing to operate in an instable manner. In order to avoid the wall slip, the limiting shear stress at the bearing surface should be higher than that at the journal surface. 相似文献
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Bibiana Luccioni Viviana C. Rougier 《International Journal of Mechanical Sciences》2010,52(4):602-611
There are many unreinforced masonry buildings all over the world. Many of them are located in seismic zones and are, therefore, susceptible to lateral forces caused by earthquakes. The transmission of these forces to the foundations is made through load bearing walls and depends on the shear strength and stiffness of masonry.In plane shear strength of load bearing masonry walls depends on many factors like the bricks and mortar strength and the way the wall is constructed. It is mainly due to shear strength of the brick-mortar interface given by the adhesion and by the friction caused by normal compression loads. Under severe seismic loads the ultimate strength capacity of the interface is achieved and the structure collapses.The results of an experimental program performed to study the shear behaviour of CFRP retrofitted and repaired masonry are presented in this paper. Increase of strength, ductility and stiffness due to the addition of CFRP laminas is specially analyzed. Specimens formed by three bricks and two mortar joints without reinforcement, retrofitted and repaired with CFRP laminas were tested under quasi-static and cyclic load.Additionally, the numerical study of the same specimens is presented. The specimens were modelled with 2D and 3D finite elements programs. Orthotropic plasticity models were used for bricks and mortar, including brick-mortar interfaces and CFRP laminas. Experimental results were used to calibrate the parameters of the material models and a numerical tool for the mechanical analysis of retrofitted or repaired masonry panels was developed. A parametric numerical study was also carried out with these numerical models in order to obtain the optimal dimensions and orientation of the reinforcing bands. 相似文献