共查询到20条相似文献,搜索用时 971 毫秒
1.
储罐在偶发爆炸载荷作用下易发生结构破坏,致使罐内储液流出,从而造成巨大的经济损失,但采用弱顶设计的储罐在此类事故发生时能减少损失。为此,以立式拱顶储罐为研究对象,综合考虑储罐破坏过程中内部压力、应力以及裂纹扩展等因素,建立了基于多判别条件的储罐内爆弱顶性能评价方法。同时,通过数值模拟手段,采用CEL(coupled Euler-Lagrange,耦合欧拉-拉格朗日)流固耦合算法建立了储罐内爆三维有限元模型,对内爆载荷作用下储罐的破坏过程及不同影响因素下储罐的弱顶性能开展研究。计算结果表明:在基于压力和应力的弱顶性能评价中,储罐在90°,135°,180°位置处的峰值压力比大于1,满足弱顶要求;在基于结构断裂的弱顶性能评价中,由于裂纹延伸到液位以下,2条裂纹分别穿过液位1.99 m和5.21 m,储罐不具备弱顶性能。随着储罐容积的增加、液位的升高,储罐的弱顶性能增强。根据计算所得结果,采取在液位以上设置防护圈的方法对储罐进行优化,使得非弱顶储罐满足弱顶结构设计要求。所建立的储罐弱顶性能评价条件可为储罐的弱顶设计及分析提供参考。 相似文献
2.
3.
4.
内蒙古博大实地5080化肥项目有10000m3常压液氨储罐2台,均为立式圆筒形低温储罐,罐顶为常见的球面拱顶结构,该拱顶板采用新型"人"字形排板方式施工,克服了传统瓜瓣板安装施工的一些不足。文章从拱顶板安装前的准备工作、排板图的绘制、安装过程中的技术控制及质量检验等,论述了该储罐顶板的施工过程。 相似文献
5.
6.
立式罐的容量通常是在空罐状态下计量的,当其内装有液体时,由于液体的静压力作用,罐体必然发生弹性形变,使罐的容量增大,该增大值称为液体静压力效应修正值,这在当今大容量计量中是必须考虑的重要问题之一。一、静压力效应修正值的计算立式罐是金属制的圆筒体。为了计算它的液体静压力修正值,首先需考究罐壁受液体静压力作用而引起的径向位移;然后,相应的修正值即可通过径向位移积分求得。 相似文献
7.
《振动与冲击》2017,(22)
半地下覆土油罐常用于储存汽油、柴油等易燃易爆油品,一旦被引燃,短时间内将产生极强的爆炸压力波,造成储罐的严重破坏并带来灾难性后果,油气爆炸冲击荷载的研究是进行储罐安全设计的基础。利用等比例模拟容器,基于实验对覆土立式油罐罐内油气爆炸冲击载荷特性进行了实验研究,获得了密闭条件下油罐内不同位置处的压力荷载的变化规律,油气爆炸压力荷载变化分为四个阶段:点火孕育期、加速突变期、衰弱振荡期、惯性波动期;罐顶位置处的压力荷载数值要明显大于罐壁和罐底处的压力荷载数值;进一步考察了初始油气浓度、初始点火能量、初始温度等相关参数对爆炸冲击荷载的影响规律。研究结果表明:爆炸超压随浓度的变化呈先增大后减小的规律,当初始浓度为1.71%时,爆炸超压荷载达到最大值。爆炸超压值与点火能成正比关系,与初始环境温度成反比关系。 相似文献
8.
目的 为了分析液氨储罐纯液体泄漏后的事故影响,探究液氨纯液体泄漏量的计算.方法 针对液氨储罐(卧罐、球罐及立式罐)液体泄漏罐压变化及不同类型储罐结构特征导致液面面积变化的特点,利用范德瓦尔斯方程和流体力学方法,建立液氨储罐液体泄漏模型.利用模型对3种液氨储罐液体泄漏进行数值模拟,对比PHAST计算与模型模拟结果.结论 结果发现液面高度hv,s,h的下降呈现先减缓后增大的趋势,泄漏质量流率Qm-v,s,h的下降幅度及泄漏质量mv,s,h呈现先增加后减缓的趋势.泄漏初始时刻,Qm-v,s,h值最大,分别为0.555,0.553,0.552 kg/s;泄漏停止时,mv,s,h值最大,分别为11.245846,11.084621,7.730932 t.模型计算结果与PHAST模拟结果规律相似,Qm-v,s,h(max)的偏差较小,介于16.577%~16.667%;mv,s,h偏差差别较大,立式罐、球罐及卧罐泄漏液体质量偏差分别为4.565%,5.764%和17.630%.结论 根据各参数的变化规律可得,模型适于计算液氨储罐液体泄漏及风险分析. 相似文献
9.
《振动与冲击》2016,(11)
对于基础隔震大型立式储罐的地震响应分析问题,考虑土壤与结构的相互作用和储罐的摆动效应,从流体速度势理论出发,结合储罐储液与罐壁的边界条件,建立液体运动势函数和相应的基底剪力、倾覆力矩及波高的理论表达式;并依据剪力和弯矩等效的原理,建立了具有摆动效应的基础隔震储罐的力学简化模型,利用能量原理建立了考虑摆动效应的立式储罐隔震体系的运动方程。同时,以15万m~3大型储罐为例,进行了减震效应数值计算分析,并与无摆动效应的隔震体系的简化力学模型进行了比较分析。结果表明:大型储罐采用基底隔震装置,可以有效地降低储罐的基底剪力,对液体晃动波高的控制效果较差,建议在高烈度区,满足晃动波高的前提下,储罐上部结构可以降低烈度进行设计。 相似文献
10.
目的为提高液体类空投物资补给效率,研究椭球型结构的无伞空投储液罐跌落冲击地面过程的力学响应。方法基于欧拉-拉格朗日耦合算法,建立含有内盛物的椭球形储液罐有限元模型,通过Abaqus CAE仿真跌落得到罐壁材料层为聚乙烯-发泡-聚乙烯在不同厚度比条件下含内盛物跌落的最大等效塑性应变(简称最大塑性应变)云图、应力-时间曲线。结果不同层间厚度比与储液罐的最大塑性应变、塑性应变的时间和应变集中区域有密切联系,当厚度比为1∶2∶1时,罐体达到最大塑性应变的时间短,把手部位出现应变集中现象的概率增大;厚度比为1∶1∶2时,罐体的塑性应变相对降低,抗冲击能力没有达到理想优化效果;厚度比为1∶1∶2时,罐体的塑性应变最小,在此情况下能承受的冲击地面的瞬时速度最大,罐体的结构性能最好。结论基于此提出了一种结构优化思路,在添加中间发泡层以减轻配重的基础上,适当增加外层聚乙烯材料的厚度或者使用缓冲性能更好的材料,增加罐壁的缓冲吸能,改善材料结构强度。 相似文献
11.
建造质量或操作不当会导致立式金属储罐发生形变,影响油罐的正常使用和安全运行及容积计量的准确度。应用激光扫描三维建模技术,研究了一种基于点云数据分析的大型立式金属罐变形测量新方法,通过迭代算法计算出每个圈板的几何半径,使用计算得到的几何半径为基础建立立式罐圈板模型的高精度模型。采用壁式移动测量平台进行局部区域形变参数的测量,实现了立式罐圈板整体和局部形变的同步测量。并以一个10104m3立式浮顶罐(直径为79.937m)为试验研究对象,验证了这种方法的有效性。 相似文献
12.
为探讨工业炸药硝酸铵溶液储罐安全措施的有效性,运用道化学火灾爆炸危险指数法对工业炸药生产用硝酸铵溶液储罐进行分析,得到了其补偿前、后的火灾爆炸指数、暴露半径、暴露区域面积、危险等级等参数。分析表明:在安全措施补偿前,硝酸铵溶液储罐的火灾爆炸指数为176.90,暴露半径为45.29 m,暴露区域面积为6 440.72 m2,危险等级为非常大;在采用工艺控制、危险物质隔离及消防设施等补偿控制措施后,火灾爆炸指数降至84.91,暴露半径降至21.74 m,暴露区域面积降至1 484.05 m2,危险等级降至较轻。证明目前采取的安全措施是有效的、可行的。 相似文献
13.
Rings and sheets of aluminium alloy AA 2219 of Al–Cu series are being used for the fabrication of propellant storage tank. Under development phase, one such tank failed in the course of qualification. Detailed metallurgical analyses were carried out on this failed tank, which revealed the presence of large number of incipiently melted & solidified particles as a result of welding/repair welding, along the grain boundaries and also within the grains nearer to weld fusion line. This has resulted in the formation of continuous film along the grain boundaries of already coarser grains of the ring. Such film which formed by liquation at the weld fusion line/HAZ, under the influence of residual stresses due to welding under fixture constraints, especially near the weld repair region, initiated the crack formation. The crack once initiated, found easy propagation through film along the grain boundaries (GB). Electron probe micro analysis (EPMA) of these particles confirmed the film as eutectic, low-melting compound and their non-uniform distribution.This paper highlights the investigations carried out on the failed tank. 相似文献
14.
15.
16.
Muhammad Sajid Ali Asghar Fawad Tariq Ashraf Ali 《Journal of Failure Analysis and Prevention》2010,10(4):303-311
This paper presents the failure analysis of AISI-304 stainless steel tank that was fabricated by welding and used for the
storage of styrene monomers. After about 13 years of satisfactory operation, significant cracking was observed adjacent to
the weld joints and in base plate near tank foundation. Weld repair was by shielded gas arc welding using AISI 308 stainless
steel filler wire. The failed base plate was replaced with the new AISI 304 base plate of same thickness. After a short period
of time, seepage was observed along the weld bead. Upon nondestructive testing cracks were found in the heat-affected zone
and in the base plate. The failure investigation was carried out on welded and base plate samples using spectroscopy, optical
and scanning electron microscopy, fractography, SEM–EDS analysis, microhardness measurements, tensile and impact testing.
The results revealed transgranular cracks in the HAZ and base plate, and the failure was attributed due to stress corrosion
cracking. Cracks initiated as a result of combined action of stresses developed during welding and the presence of a chloride
containing environment due to seawater. It was further observed that improper welding parameters were employed for weld repair
which resulted in sensitization of the structure and postweld heat treatment to remove weld sensitization and minimize the
residual stresses was not done. 相似文献
17.
基于传统索穹顶构造形式的单一性和力学性能的不足,提出了一种空间三撑杆双环索索穹顶。提出了一种基于位移法与节点平衡法结合求解索、杆预应力的方法,并运用该方法计算比较了该索穹顶结构在是否考虑自重情况下预应力分布的差别;给出了索穹顶在考虑不同参数影响下的预应力计算表,对比了各种参数对结构性能的影响。结果表明:在考虑结构自重情况下,该索穹顶绝大部分索、杆预应力值都有不同程度的增大;撑杆高度与矢跨比的增大,会导致索穹顶结构中几乎所有构件的初始预应力值呈现减小的趋势,但增大撑杆高度相较于增大矢跨比影响更大。因此,在实际工程中,更多采用增大撑杆高度的方案。 相似文献
18.
High strain rate deformation and cracking of AA 2219 aluminium alloy welded propellant tank 总被引:1,自引:0,他引:1
Abhay K. Jha S.V.S.N. Murty K. Sreekumar P.P. Sinha 《Engineering Failure Analysis》2009,16(7):2209-2216
Aluminium alloy AA 2219 (Al–6.6Cu–1Mn) is the candidate material for the fabrication of propellant storage tank of launch vehicle. Cold rolled sheets of 6.5 mm thickness are used to make the cylindrical shell, while sheets of 4.5 mm thickness are used for the construction of dome through petal forming technique. Petals, formed through cone rolling, treated to T87 temper condition are welded together by TIG welding to configure the dome. Such domes are joined to the cylindrical shell through a ring by TIG welding.The upper stage consists of two tanks, one oxidizer tank (liq. O2) and other fuel tank (liq. H2). After completing various developmental qualification tests, propellant flow rate test of one of the system was carried out. Almost all the liquid oxygen of the tank was removed and only a little quantity remained at the bottom. During one of the subsequent tests; when dry nitrogen gas was purged to evaporate the remaining liquid oxygen, the oxidizer tank dome catastrophically fractured with an audible sound. Fracture of oxidizer tank dome, placed at lower part of the system caused excessive deformation and subsequently it also caused fracture of fuel tank dome placed just over it.Detailed metallurgical investigations were carried out on the failed components and it was found that the tank failed under very high strain rate deformation. This paper brings out the details of the investigation carried out. 相似文献
19.
运用基于AZ31镁合金本构方程与ALE算法的HyperXtrude软件对典型AZ31薄壁管材的挤压过程进行数值模拟,并通过调整焊合室高度、焊合室大圆角及焊合室坡度3个结构参数,分析不同条件下应力分布与速率分布的变化情况。结果表明:焊合室内近工作带处压力随焊合室高度增加不断减小,分流孔与焊合室压力的最大值与平均值均随焊合室大圆角增大发生降低,分流孔与焊合室压力随焊合室入口坡度增大不断增大,并在焊合室高度为16mm、大圆角为18mm以及入口坡度为15°时金属流速均方差达到最小值。优化模具结构缓解了应力集中与流速不均等问题,在实验生产中得到合格产品,型材组织均匀细化。 相似文献
20.
为了避免因液体晃动过大而引起的储罐"象足"型失稳破坏,采用减晃板作为抑晃装置并对其进行了减晃优化设计。分别采用缩尺模型试验(缩尺比1∶30)和有限元分析等手段对有、无安装减晃板的储罐内的液体晃动波高、罐底剪力及罐壁压应力等关键指标进行了实测和仿真模拟。研究结果表明:关键指标的模拟值与实测值较为接近,进而验证了储罐减晃有限元分析的可靠性;当减晃板在距液面0.125倍~0.225倍的储罐高度且其宽度在0.15倍的储罐半径附近时,减晃板对储液晃动波高、罐底剪力及罐壁压应力都具有较好的抑制效果;减晃优化设计后,"象足"失稳区(接近罐底处)的罐壁压应力峰值得到了较为显著的抑制。 相似文献