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为了探求大型拱顶储罐的合理设计方法, 在本文中给出了一个直径为2.5m 的模型罐在内压及拱顶雪载作用下的弹性应力测试与内压弹性失稳的实验结果。罐的拱顶为加肋球壳, 承压圈为圆环壳, 肋与壳之间为间断焊接。文中给出了计及加强肋与不计及加强肋两种不同的有限元计算方案 (分别简称有肋与无肋方案) 所得数值解与实测值的比较。结果表明: 对于肋与壳间断焊的情况在内压作用下, 应力测试实验值与弹性内压失稳临界压力和按无肋方案计算值相一致;在拱顶雪载作用下, 应力测试值与按有肋方案计算值一致。实验还表明对于大型拱顶储罐,采用圆环壳型的承压圈有较好的承载能力, 这是一种合理的结构型式。 相似文献
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随着成品油储罐的大型化发展,采用空间网壳结构作为储罐罐顶已成为必然趋势。虽然网壳结构在建筑行业已有成熟的理论和设计经验,但如何应用于大型储罐还存在很多技术问题。比较分析现有大型网壳结构形式的优劣,针对大型拱顶网壳储罐结构特点,给出网壳顶网格类型、杆件截面、节点形式的选型意见;为提高网壳顶与下部罐体连接的安全性,自主提出一种可用于大型拱顶网壳储罐的新型支座结构;研究网壳顶整体稳定性的计算方法,采用考虑几何非线性的荷载-位移全过程分析方法,计算得到拱顶网壳储罐结构的临界失稳荷载,分析下部罐体、不同约束方式和不同安装偏差对拱顶网壳稳定承载力的影响;并依据JGJ7-2010《空间网格结构技术规程》等建筑行业规范标准,以一50 000 m3大型拱顶网壳储罐为例对稳定性计算进行案例分析,验证相关规范同样适用于储罐网壳。 相似文献
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论文分析说明了不同壳体上的开孔,开孔直接的确定准则,论述了常用开孔补强结构型式(即补强圈补强和整体补强)的补强效果:整体锻件补强优于厚壁管补强优于补强圈补强型,并给出了两种补强结构的适用范围。 相似文献
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近年来,随着低温储罐的尺寸、体积越来越大,其建造施工难度和风险所带来的困难与挑战已开始被国内外学者所重视。采用低温储罐拱顶、内吊顶及顶部接管立体化施工的方法,解决了整体气顶升过程中各装置不能达到立体化施工效果的难题,有效降低了整体气顶升的施工难度和安全风险。采用统一标准的钢丝绳在平衡校正系统及配重系统中360°空间内进行等角度的布置、施加恒定预紧力,实现了储罐拱顶上升过程中的平衡和稳定,达到了为储罐拱顶准确提供定位和导向的目标。采用顶升自动监控系统(JAMS)对整体气顶升施工进行监测、控制,实现了对顶升压力和罐顶(吊顶)上升速度的控制,保证了罐顶(吊顶)的平稳顶升,降低了顶升施工过程中的安全风险。 相似文献
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强力锁紧圈(POWERLOCK)是一种新型的无键联接元件。它与一般的键联接、压入联接、热压联接相比具有安装简便,无须加工键槽而影响零件强度,定位方便尤其是相位微量可调等优点。此外还具有占空间小、重量轻、有密封性能等特点。强力锁紧圈联接能承受一定的扭矩和轴向力,省却轴向止推机构,能承受一定的冲击载菏和振动,可多次装卸重复使用等等,可用于各种齿轮、皮带轮、手轮和凸轮之类轮壳型零件同轴的联接,在机械结构中得到越来越广泛的应用。在日本等国,强力锁紧圈已成为由专业工厂生产的标准件供各用户选用。现将EL系列强力锁紧圈的工作原理,规格型号,选用设计计算方法简介如下: 相似文献
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开发了一种适用于喷灌泵的导叶式压水室,导叶为不对称型式,三个导叶具有各自不同的设计形式。试验结果表明,这种导叶式喷灌泵是理想的喷灌用泵,其自吸性能良好,流量一扬程曲线平坦。同时,与涡壳式压水室相比,导叶式压水室结构简单,便于采用新材料和新工艺进行制造。 相似文献
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国外关于圆柱壳开孔接管问题的研究概况 总被引:26,自引:3,他引:26
1.引言圆柱壳开孔接管是在压力容器设计中最常遇到的问题之一。通常可分为两种情况:容器开孔接管与大型管道三通(T型、Y型等)。无论何种情况,一般说来,结构所承受的载荷(此处尚未涉及温度应力)应包括:(1)内压;(2)作用在接管上的外载荷,可以分解为三个 相似文献
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S.-Y. Leu 《International Journal of Mechanical Sciences》2008,50(12):1578-1585
The paper aims to assess plastic limit loads of thick-walled hollow cylinders of strain-hardening viscoplastic materials under internal pressure. Particularly, the problem concerned features in the interaction between strengthening and weakening behavior during the deformation process. Therefore, the relating onset of instability and the stability condition also deserve to be further investigated. Analytical and finite-element limit analysis efforts are both made for complete and comparative investigation. By the concept of sequential limit analysis, the plastic limit loads were acquired by solving a sequence of limit analysis problems via computational optimization techniques. Applying the velocity control as a computational strategy to simulate the action of pressure, the paper investigates analytically and numerically the plastic limit load, the onset of instability and the stability condition of plane-strain circular cylinders. Especially, analytical solutions of the onset of instability were solved explicitly by the fixed point iteration. Validation of the present analytical and finite-element efforts was made completely with good agreement between the analytical solutions and the numerical results. 相似文献
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内压作用下局部减薄弯管塑性极限载荷分析与试验研究 总被引:9,自引:3,他引:9
采用有限元分析法和试验测定法,对内压作用下局部减薄弯管的极限载荷进行研究。由有限元计算结果数据拟合出局部减薄弯管塑性极限内压的计算公式,并通过试验验证了该公式。 相似文献
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Yun-Jae Kim Kuk-Hee Lee Chang-Sik Oh Bong Yoo Chi-Yong Park 《International Journal of Mechanical Sciences》2007,49(12):1413-1424
This paper quantifies the effect of a bend angle of a pipe bend on plastic loads, via small strain and large strain finite element (FE) limit analyses using elastic–perfectly plastic materials. To consider the effect of the attached straight pipe, two limiting cases are considered. One case corresponds to the pipe bend without the attached straight pipe, and the other to that with a sufficiently long attached straight pipe. For the former case, the FE results suggest that the limit load is not affected by the bend angle for both in-plane bending and internal pressure. For the latter case, however, the bend angle affects plastic loads. An interesting finding is that the plastic load smoothly changes from the limit load of the straight pipe when the bend angle approaches zero to the plastic load of the 90 pipe bend when the bend angle approaches 90. Based on such observations, closed-form plastic load solutions are proposed for the pipe bend with an arbitrary bend angle under in-plane bending and internal pressure. 相似文献
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内压作用下弯管塑性极限载荷分析与试验研究 总被引:6,自引:2,他引:6
对在内压作用下弯管的极限载荷进行研究。研究采用了有限元分析法、公式计算法和试验测定法。有限元分析结果表明,弯管的极限载荷随着弯管壁厚和弯曲半径的增加而增加,并与Goodall公式计算结果一致,最大误差为6.58%。这些结果得到了试验测试的证明。 相似文献
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到目前为止,还没有文献给中向裂纹管道在非对称弯曲及扭转组合变形时的塑性极限载荷计算公式。文中根据净截面垮塌准则用沙堆比拟法分别求出埋藏裂纹、外表面裂纹、内表面裂纹、穿透裂纹管道发生扭转变形时的塑性极限扭矩;给出含周向裂纹薄壁管道横截面上的剪应力分布规律,其塑性极限扭矩等于一个闭口薄壁截面与一个开口薄壁截面圆环的塑性极限扭矩之和,闭口薄壁截面的壁厚为管道壁厚减裂纹深度;开口薄壁截面的壁厚为裂纹的深度。推导了各种周向裂纹管在内压、轴力、扭矩及非对称弯矩共同作用时的塑性极限载荷关系式,并由此给出其他一些组合变形时的极限载荷计算公式。本文结果可供管道安全评价时参考。 相似文献
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Fu-Zhen Xuan Pei-Ning Li Shan-Tung Tu 《International Journal of Mechanical Sciences》2006,48(4):460-467
An approximate analysis approach for plastic limit load of piping branch junctions, by means of the relationship of the internal force between the main and branch pipes around intersection line, is presented in this work. The approach is built on the following process: based on the external force equilibrium condition, an equation between the limit load and internal force of the branch pipe around intersection is derived firstly. And then, taking this internal force as an external force acting on the intersection of the main pipe, the approximate solution of the internal force around the intersection on the main pipe is given as a function of the limit load. Finally, referring to the von-Mises yield criterion, the limit load of component with two intersecting cylindrical shells is then obtained. In use of the proposed approach, a closed form of limit load solution for piping branch junction under in-plane moment is developed. Finite element (FE) models of the idealized piping branch junction with various diameters and wall-thickness of the main and branch pipes were analyzed by using nonlinear FE software. The limit loads from FE analysis, from the proposed solution and six experimental data of real piping branch junctions are compared. Overall good agreement between the different limit loads was observed which provides confidence in the use of the proposed formulae in practice. 相似文献