共查询到20条相似文献,搜索用时 125 毫秒
1.
简述并研究了对蒸汽发生器人孔应力的计算方法,提出了选择轴对称谐单元模型对蒸汽发生器人孔进行应力计算,轴对称谐单元模型的应力计算分析方法适合人孔的应力计算,它的计算方法简单、可操作性好且易实现材料和结构的疲劳分析和计算,其应力评定便捷且符合RC C-M规范。人孔、盖板、螺栓孔区域,法兰结构、螺栓孔区域采用等效弹性模量和等效泊松比方法进行模型简化,简化模型简化了应力计算,简化模型应力计算结果保守且满足RC C -M规范要求。轴对称谐单元模型进行人孔设计工况下的应力计算方法可推广应用于蒸汽发生器人孔在其他工况下的应力计算及其密封设计计算。 相似文献
2.
3.
4.
15×104 m3超大型石油储罐结构优化分析 总被引:1,自引:0,他引:1
为了提高超大型石油储罐的安全性能,开展了15×104m3油罐的结构优化分析。比较了罐体壁板和底板应力的几种计算方法,提出采用“组合圆柱壳法”计算壁板应力以及采用基于沉降量的有限元法计算底板应力;参照美国API 650和日本JIS B 8501设计规范制订了4种结构设计方案,计算得到各方案中壁板应力与底板应力大小,并进行相互比较。分析结果表明,参照美国API650标准设计并选用宽幅钢板的结构设计方案四理论计算应力最小,且应力评定合格。 相似文献
5.
堆内构件上支承组件采用不同的建模方法,分别采用壳单元和梁单元相组合的建模模式、壳单元和壳单元相组合的建模模式、实体单元建模的模式,对堆内构件上支承组件进行了有限元应力计算,比较了不同建模模式下应力计算的各自特点,堆内构件上支承组件实体单元建模模式应力计算结果精确并能满足RCC-M规范应力评定要求,壳单元和梁单元相组合的建模模式、壳单元和壳单元相组合的建模模式应力计算结果保守且应力评定需等效处理其计算结果。堆内构件上支承组件采用整体实体单元全模型建模的计算方法,计算精确且应力评定简单直接,它可应用于其他工况和不同堆芯堆内构件应力计算及其应力评定。 相似文献
6.
磨削加工齿轮的残余应力状态对齿轮使役性能有较大影响,磨削后齿面的表面残余应力准确预测与计算是齿轮抗疲劳制造的重要内容。基于成形磨削运动分析及热力耦合有限元仿真计算方法,提出了齿轮成形磨削加工齿面残余应力计算方法。开展成形磨削实验,测量磨削后齿面的残余应力,对比分析残余应力实验测量值与有限元计算值,分析了磨削加工参数与残余应力的关联规律。结果表明,提出的成形磨削齿面残余应力计算方法得到的计算值与实验测试结果具有较好的一致性;在成形磨削中,砂轮进给深度越大,齿面残余拉应力越小。 相似文献
7.
8.
介绍了受冲击变截面杆件圆弧过渡部位的应力计算方法。该应力的大小可由按一维纵向应力波理论计算得到的应力σ乘以圆弧过渡部位的应力集中系数β得到。并通过动光弹实验检验,证实了本方法对受冲击杆件圆弧过渡部位应力计算的适用性和准确性,从而使受冲击杆形零件的应力计算得以完善。 相似文献
9.
10.
运用有限元软件分析了柴油机曲轴在交变弯曲载荷下的应力分布和疲劳强度。以最大爆发压力工况和最大拉力工况作为计算工况,计算了曲轴的应力分布;对最大爆发压力工况和最大拉力工况下的应力进行等效转化疲劳应力计算;最后采用安全系数判断了曲轴的疲劳强度。 相似文献
11.
12.
13.
14.
15.
16.
轧机压下螺纹副回松机理试验和铜螺母螺牙塑扁鼓包分析 总被引:2,自引:0,他引:2
为定量解明中厚板轧机压下螺纹副回松机理和铜螺母螺牙顶端塑性压缩变形鼓包现象,制作中厚板轧机螺纹副1/8实物模型,进行螺纹副压下螺钉回松量测试、振动试验和铜螺母螺牙塑性压扁及顶端鼓包的有限元数值分析.轧机压下螺纹副采用大间隙中径定位力学约束.在轧制及间歇振动及咬、甩钢载荷工况下,由于螺纹副力学约束定位而侧隙控制的不可靠性,每当发生压下螺钉与平衡机构之间的不同步运动场合,诱发压下螺钉回松或螺牙顶端产生塑性压扁鼓包现象.提出主/副复合螺母结构,副螺母靠螺牙背面对压下螺钉实现几何约束以取代中径定位力学约束,有效地防止螺纹副动态侧隙的发生而分离,实现压下螺钉自平衡,减小压下螺钉的回松量,防止铜螺母螺牙产生塑扁鼓包.同时,减缓铜螺母的磨损,成倍增加螺纹副工作寿命. 相似文献
17.
S. Malayappan G. Esakkimuthu 《The International Journal of Advanced Manufacturing Technology》2006,29(1-2):41-48
The friction forces developed between the work-piece and the forming tools are of important consideration in metalworking.
In many metalworking processes friction is the pre-dominant factor. This project has been taken up to experimentally study
the effect of barreling of aluminium solid cylinders during cold upsetting by introducing different lubricants at one end
of the solid cylinder. Experiments were conducted for three aspect ratios. The radius of curvature of bulge measured was found
to conform to the calculated one using experimental data. The calculations are made with the assumption that the curvature
of the bulge followed the form of a circular arc. A relationship was established between the various bulge parameters like
new hoop strain, geometrical shape factor(1) geometrical shape factor(2) and stress ratio parameter. 相似文献
18.
An experimental analysis of upset forging of aluminium cylindrical billets considering the dissimilar frictional conditions at flat die surfaces 总被引:6,自引:6,他引:0
S. Malayappan R. Narayanasamy 《The International Journal of Advanced Manufacturing Technology》2004,23(9-10):636-643
Friction plays a major role in all bulk metal forming processes, except in a few isolated cases such as die-less wire drawings, etc. In upset cold forging, the existence of frictional constraints between the dies and the work-piece directly affect the plastic deformation of the latter. When a solid cylinder is compressed axially between the top and bottom platen, the work piece material in contact with their surfaces undergoes heterogeneous deformation resulting in “barrelling” of the cylinder. The friction at the faces of contact retards the plastic flow of metal on the surface and in its vicinity. A conical wedge of a relatively undeformed metal is formed which suffers high strain hardening and bulges out in the form of a barrel. This experimental work has been undertaken to study the bulging effect of aluminium solid cylinders, varying the frictional conditions at the flat die surfaces. Flat dies of different surface finish were produced by different machining processes like grinding, milling, electro-spark machining, and lathe turning and finishing with ‘0’ grade emery paper. Experiments were conducted for two aspect ratios. The radius of curvature of bulge was measured and found to conform to the calculated bulge using experimental data. The calculations are made with the assumption that the curvature of the bulge followed the form of a circular arc. A relationship was established between the various bulge parameters including new hoop strain, hydrostatic stress, geometrical shape factor, and stress ratio factor, considering the dissimilar frictional conditions. 相似文献
19.
20.
板料成形时极限拉深系数的确定 总被引:2,自引:1,他引:1
以金属板料拉深成形时凸模圆角处和凸缘区金属的变形为基础,提出了一个确定板料成形时极限拉深系数的判据。该判据可用于定量研究材质和成形工艺参数对极限拉深系数m k值的影响。并且,在金属板料拉深成形时凸模圆角处金属的变形分析的基础上,应用本文判据导出了平底杯型件拉深时极限拉深系数的计算式。同时,从计算结果的分析中,进一步阐明了板料拉深时合理工艺参数的选择依据。试验结果表明:该判据确定的极限拉深系数m k值准确,且其适用性强。 相似文献