The Experimental Study Of Compression And Instability Of Thin Walled Spherical Shells

Thin walled spherical shells are widely used in many fields. Examples include aircraft, spacecraft, automobiles, nuclear reactors, steel silos, tanks for solid and liquid storage as well as their transportation。That is important to study their buckling behavior. Thin spherical shell of the local impact loads will have important theoretical and practical value in the research work. With the attention on the structural safety, more and more investigative will be on the mechanical characteristics of thin-walled spherical shell.In this paper, we present static and dynamic compression experiments on thin-walled shell made of stainless steel. By a static analysis of data which were obtained from the experiment of thin-walled spherical shell. The results show: It is related between the critical buckling displacementδc/t and R/t when the thin spherical shell in compression, as the feature size of thin-walled spherical shell with R/t increased, the critical turning displacementδc/t increased. Compare the calculated curvet and experiment curve, the calculated curve of elastic model match well in the stage of shell flattened. The calculated curve of rigid-plastic model, results match the experiments not well in the stage of shell flattened. With the compressive displacement increased, calculated curves and experimental curves match well. Dynamic compression test is carried out on the Hopkinson Bar. Dynamic data mainly including dynamic displacement - time curve and force - time curve. And two curves obtained for a detailed description. Obtained the force - displacement curve under different the impact velocities. On the curve obtained with a comparative analysis of the static curve. The analysis shows that: At the beginning of the experiment, the dynamic compression force is less than the static compressive force. The thin-walled spherical shell with the same R/t in the dynamic experiment, the radius, the thickness of the thin-walled spherical shell is smaller, the required compression force smaller. Thin-walled spherical shell is easier to deform non-symmetric buckling under the dynamic experiment, with the increase of impact velocity, the number of walls that thin shell instability formation to increase. Dynamic tests were conducted on the finite element method. In the case of the finite element analysis and experimental results agree well, calculated by finite element, Thin-walled shell needed to produce non-symmetric buckling of the compression displacement and compression force increased with increasing impact velocity.