共查询到17条相似文献,搜索用时 78 毫秒
1.
2.
根据已有的实验现象假定变形模态,采用Lagrange方法分析了单位长度薄圆环在余弦冲击载荷作用下的弹性脉冲动屈曲。导出了动力屈曲方程组,借助数值方法求解方程,并与已有的计算进行了比较,得出结论 相似文献
3.
圆柱壳在侧向非对称冲击载荷下的塑性动力屈曲 总被引:2,自引:1,他引:2
采用塑性动力屈曲能量准则,对圆柱壳非均匀局部径向冲击下的塑性动力屈曲进行了研究。文中分别采用弹性的角弹簧和位移弹簧模拟非屈曲部分对屈曲部分的影响,推导了有关模态和临界速度的冲击公式,并与有关的实验结果进行了比较,分析了两种边界对塑性动力屈曲的影响。 相似文献
4.
5.
6.
7.
本文采用王仁等提出的塑性动力屈曲的能量准则讨论了圆柱壳在不均匀的外部径向冲击下的塑性动屈曲问题。获得了屈曲的占优波数公式及临界冲击速度公式,初步的实验证明本文的结论是合理的。同时进一步证明该能量准则的有效性。 相似文献
8.
非均匀径向冲击下圆柱壳塑性动屈曲 总被引:2,自引:0,他引:2
本文采用王仁等提出的塑性动力屈曲的能量准则讨论了圆柱壳在不均匀外部径向冲击下的塑性动力屈曲问题,获得了屈曲的占优波数公式及临界冲击速度公式,初步的实验证明本文的结论是合理的.同时进一步证实该能量准则的有效性. 相似文献
9.
10.
本文对结构动力屈曲的特征、分类、屈曲准则等作了一般性讨论,对流固冲击屈曲,动力屈曲的缺陷模型等作了专题讨论。最后对圆柱壳的塑性动力屈曲作了全面回顾。 相似文献
11.
对钢质和铜质金属圆柱壳的轴向冲击动力响应进行了实验研究,记录了两种不同材料圆柱壳在大质量低速冲击下的冲击力时程曲线,得到其屈曲模态。采用高速摄像及模拟技术给出了钢质圆柱壳渐进屈曲的全过程,为理解钢质圆柱壳的屈曲机理提供了直观的结果。黄铜质圆柱壳在大质量低速冲击下, 出现整个壳面滿布屈曲波纹的塑性动力屈曲现象,说明高速冲击不是产生塑性动力屈曲的充要条件。像铜这样具有高密度的韧性材料,在大质量低速冲击下,会在轴向产生持续的压缩塑性流作用而出现塑性动力屈曲现象。 相似文献
12.
《Acta Mechanica Solida Sinica》2017,(3)
The stress wave propagation law and dynamic buckling critical velocity are formulated and solved by considering a general axial connecting boundary for a slender elastic straight rod impacted by a rigid body. The influence of connecting stiffness on the critical velocity is investigated with varied impactor mass and buckling time. The influences of rod length and rod mass on the critical velocity are also discussed. It is found that greater connecting stiffness leads to larger stress amplitude, and further results in lower critical velocity. It is particularly noteworthy that when the connecting stiffness is less than a certain value,dynamic buckling only occurs before stress wave reflects off the connecting end. It is also shown that longer rod with larger slenderness ratio is easier to buckle, and the critical velocity for a larger-mass rod is higher than that for a lighter rod with the same geometry. 相似文献
13.
Experimental studies on dynamic plastic buckling of circular cylindrical shells under axial impact 总被引:1,自引:0,他引:1
In the present paper, experimental studies on dynamic plasticbuckling of circular cylindrical shells under axial impact are
carried out. Hopkinson bar and drop hammer apparatus are used for dynamic loading. Three groups of circular cylindrical shells
made of copper are tested under axial impact. From the experiments, the first critical velocity corresponding to the axi-symmetric
buckling mode and the second critical velocity corresponding to the non-axisymmetric buckling mode are determined. The present
results come close to those of second critical velocity given by Wang Ren[4–6]. Two different kinds of non-axisymmetric buckling modes oval-shaped and triangle shaped are founded. The buckling modes under
two loading cases, viz. with small mass but high velocity and with large mass and low velocity using Hopkinson bar and drop
hammer, are different. Their critical energies are also discussed.
The project is supported by the National Natural Science Foundation of China (19672039) and the Foundation for Returned Scholar
from Abroad of Shanxi Province 相似文献
14.
《International Journal of Solids and Structures》2004,41(5-6):1565-1580
The influence of impact velocity and material characteristics on the dynamic buckling response of circular shells subjected to axial impact loads is studied. It is shown experimentally that the critical buckling length, which marks the transition between progressive and global buckling of aluminium alloy circular tubes, is significantly influenced by the axial impact velocity. A finite element analysis is undertaken to further explore the effects of material yield stress, strain hardening and strain rate sensitivity on the transition phenomenon. It is observed that circular tubes made of ductile alloys with a high yield stress and low strain hardening characteristics have a better performance as energy absorbers than tubes made of alloys with a low yield stress and high strain hardening characteristics. Theoretical analysis of some particular features of the dynamic buckling transition is presented in Part II [International Journal of Solids and Structures (2004)]. 相似文献
15.
By using the energy criterion in[3],the impact torsional buckling for the rigid plastic cylindrical shell is studied.The linear dynamic torsional buckling equations for the rigid plastic shell is drived,and the critical impact velocity is given. 相似文献
16.
D. KaragiozovaNorman Jones 《International Journal of Non》2002,37(7):1223-1238
Some characteristic features of the dynamic inelastic buckling behaviour of cylindrical shells subjected to axial impact loads are discussed. It is shown that the material properties and their approximations in the plastic range influence the initial instability pattern and the final buckling shape of a shell having a given geometry. The phenomena of dynamic plastic buckling (when the entire length of a cylindrical shell wrinkles before the development of large radial displacements) and dynamic progressive buckling (when the folds in a cylindrical shell form sequentially) are analysed from the viewpoint of stress wave propagation resulting from an axial impact. It is shown that a high velocity impact causes an instantaneously applied load, with a maximum value at t=0 and whether or not this load causes an inelastic collapse depends on the magnitude of the initial kinetic energy. 相似文献
17.
An experimental investigation on the dynamic axial buckling of cylindrical shells using a Kolsky Bar
Several experiments were performed with a Kolsky Bar (Split Hopkinson Pressure Bar) device to investigate the dynamic axial
buckling of cylindrical shells. The Kolsky Bar is a loading as well as a measuring device which can subject the shells to
a fairly good square pulse. An attempt is made to understand the interaction between the stress wave and the dynamic buckling
of cylindrical shells. It is suggested that the dynamic axial buckling of the shells, elastic or elasto-plastic, is mainly
due to the compressive wave rather than the flexural or bending wave. The experimental results seem to support the two critical
velocity theory for plastic buckling, withV
c1
corresponding to an axisymmetric buckling mode andV
c2
corresponding to a non-symmetric buckling mode.
The project supported by National Natural Science Foundation of China 相似文献