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针对正交各向异性钛制外压圆柱壳-锥壳结构,应用有限元非线性屈曲分析,较为系统地讨论了不同锥壳半顶角、锥形比与径厚比参数下圆柱壳-锥壳三种组合形式临界压力Pcr的变化规律。研究结果表明:对于圆柱壳-锥壳(大端)结构,当圆柱壳的长径比LT/DL达到一定值时,临界失稳压力主要取决于圆柱壳的结构参数;对于圆柱壳-锥壳(小端)结构,锥壳结构参数对总体结构失稳临界压力有一定影响;圆柱壳-锥壳(大小端)结构因其临界压力与对应的圆柱壳-锥壳(大端或小端)结构中易失稳一方几乎相同,可将其分别视为对应的圆柱壳-锥壳(大端或小端)结构进行稳定性分析。结果为正交各向异性钛制外压圆柱壳-锥壳结构设计方法提供依据。 相似文献
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GB150—89“钢制压力容器”中规定:对于锥形封头大端,当锥壳半顶角α≤30°时,可以采用无折边结构;当α>30°时,应采用带折边结构,否则应按应力分析的方法进行设计。但是有些在役容器锥壳半顶角α≤45°仍采用无折边 相似文献
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针对外压作用下球形封头开孔接管结构,采用有限元非线性屈曲分析方法,探讨不同结构参数对其临界失稳压力Pcr的影响.研究结果表明,当球壳主体参数径厚比一定时,临界失稳压力削弱系数K随开孔率增大而下降,随接管与封头厚度比增大而增大.接管与封头厚度比较小时,计算模型失稳位置位于接管;接管与封头厚度比增至一定值时,计算模型失稳位... 相似文献
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本文重点研究了内外壁间的间隙、几何形状偏差及残余应力对外壁受刚性约束外压圆筒失稳临界压力的影响。试验表明,间隙是影响临界压力大小的决定性因素,且存在一个临界间隙值。对于钢制圆筒,在间隙小于临界值时,随着间隙的减小,临界压力可大幅度地升高至达拉姆公式计算值的1.8~3.3倍;当间隙大于临界值时,临界压力升高不明显,且随着间隙的增大减小至外壁无刚性约束外压圆筒的临界压力而恒定不变。试验还表明,几何形状偏差会使临界压力严重下降。类似化工设备中的卷焊钢制圆筒松衬里,在其焊缝附近无直边、局部椭圆度不大于0.36%,且间隙小于某值时,其临界压力均可达拉姆公式计算值的2倍以上。 相似文献
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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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主要针对升降横移类立体车库的钢架结构稳定性进行研究,通过非线性屈曲分析法求出立体车库的屈曲载荷,为立体车库的设计提供参考。 相似文献
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以塔式起重机的金属结构为主要研究对象,借助有限元平台,从简单杆件的分析入手获得了可行的线性屈曲与非线性屈曲分析的方法与流程,进而以此为基础从不同侧面对塔机桁架结构的屈曲问题进行了详细分析.研究结果表明:考虑载荷偏心和初始位移非线性屈曲分析的结果要比线性特征值屈曲分析的结果更符合实际状态.在塔机上计算时只考虑5%的载荷偏心就使结果比原来小了33%,而在实际情况中由于小车轨道不平、风载荷等原因引起的载荷偏心可能会更严重. 相似文献
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Horizontal cylinder-in-cylinder buckling under compression and torsion: Review and application to composite drill pipe 总被引:2,自引:0,他引:2
Nathan Wicks Brian L. Wardle Demos Pafitis 《International Journal of Mechanical Sciences》2008,50(3):538-549
Available analytical results and experiments on the structural behavior of constrained horizontal cylinders subjected to axial compression, torsion, and gravitational loads are reviewed. Such configurations are of interest to the oil-drilling field and provide static design expressions for steel tubulars. The buckling problem is similar to restrained railroad tracks and submerged/underwater pipelines under thermal expansion. Due to outer cylinder constraint and gravitational loads, analysis has shown that long cylinders initiate buckling at loads significantly higher than classical Euler buckling loads. For these constrained long cylinders, buckling initiates in a sinusoidal mode that snakes along the lower surface of the constraining cylinder. Classic analytical expressions hold that as the axial load increases, the cylinder achieves an overall helically buckled state in which the buckled cylinder forms a helix spiraling around the inner surface of the constraining cylinder. Torsion is shown to have little effect on either buckling load but controls the sense/direction of the helical buckling. Little experimental data exist on constrained cylinder buckling, and it is unclear how the initiating sinusoidal mode transitions to the helical mode. Implications of the buckling progression for composite cylinder applications are described including the finding that composites perform poorly relative to steel on the metric of buckling due to lower density and axial stiffness; composites perform well on the metric of lock-up length when friction is considered. Based on this review and findings for composite cylinders, recommendations are made for further work. 相似文献
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Local and distortional buckling of cold-formed zed-section beams under uniformly distributed transverse loads 总被引:1,自引:0,他引:1
Xiao-ting Chu Zhi-ming Ye Long-yuan Li Roger Kettle 《International Journal of Mechanical Sciences》2006,48(4):378-388
This paper presents a numerical investigation on the local and distortional buckling behaviour of cold-formed steel zed-section beams subjected to uniformly distributed transverse loads. The analysis is performed using a semi-analytical finite strip method. The beams investigated include both detached sections and restrained sections. The results obtained from the present study highlight the differences in the local and distortional buckling behaviours of the thin-walled sections between pure bending and the uniformly distributed loading. 相似文献
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针对国内工程力学教材普遍认为细长压杆失稳变形挠曲线线性化方程中的挠度值不确定的错误观点,指出其对细长压杆失稳变形挠曲线线性化方程推导存在误区,以两端铰支细长压杆为例,建立了其失稳变形挠曲线线性化方程后,又考虑了压杆失稳后两端截面形心产生轴向位移参数,通过消参,确定了细长压杆失稳时最大挠度值。结果表明:压杆失稳后两端截面形心产生轴向位移以及临界压力的确定这两个条件缺一不可才能在线性化下确定细长压杆失稳时最大挠度值,挠度值的大小与轴向压力直接有关。 相似文献
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Solutions for the plastic bending of clamped polygonal plates are investigated. For an isosceles triangular plate, and for a truncated isosceles triangular plate, minima exist for plastic work of formation with respect to angles of the triangle, and location of the apex of the deformed pyramid shape. A characteristic number of radial buckles is formed when the foil circular top of British one-pint milk bottles is pushed in and material drawn over the rim of the bottle on opening. The plastic bending analysis provides an approximate means of predicting the number of buckles. 相似文献