Research On Thermal Stress Of Discrete Multilayered Vessels

Explosion containment vessel is a device used for confining potential danger. It can restrict shock wave and production of explosion, effectively protect the test personnel and equipment near from the explosion, and facilitate the observation and testing of the explosion and detonation process. Therefore, it is widely used in national defense, fabrication using explosion process, storage and transportation of dangerous substances, scientific research and other fields. Because of the development of Military, fabrication and scientific research, there is a larger capacity trend of explosion containment vessels. With the capacity development of explosion containment vessels, the inherent shortcomings of the currently widely used single shell explosion containment vessels gradually reveal themselves. For instance, the manufacturing difficulties, high costs, and difficult quality assurance of the thick steel plate (Forge). Therefore, it is a very important to develop new type explosion containment vessel.Based on the National Natural Science Foundation "Analysis of Dynamic Elastic Response and Lifetime of Confined Multi-Layered Cylindrical Vessel under Strong Dynamic Load"(No.:10372091) and "Investigation on Method for Design of Multilayered Cylindrical Explosion Containment Vessels"(No.: 50675195), the dynamic response of the DMCECV subjected to the thermal impact is studied. The study of dynamic thermal-elastic response of the DMCECV under the thermal shock is divided into three parts:(1) Theoretical Analysis on thermal shock. The displacement solution of the dynamic equilibrium equations of both inner shell and outer ribbon layer of discrete multi-layered explosion containers can be decomposed into two parts, i.e., a thermo-elastic solution for inhomogeneous stress boundary conditions and a dynamic solution for homogeneous stress boundary conditions, under given initial conditions. The dynamic thermo-elastic solution is determined by linearity method and stress boundary conditions, and the dynamic solution is worked out by means of finite Hankel transform. By using radial displacement continuity, a second kind Volterraintegral equation is derived. Interpolation functions are used to approximate the unknown function in each time subinterval. The dynamic thermo-elastic solution caused by thermal shock on DMCECV is then determined. The thermo-elastic solution of a DMCECV is compared with the solution of a monobloc cylindrical shell, in order to verify the accuracy of theoretical solution.(2) Numerical simulation of the heat shock response without considering the thermal conductivity. DMCECV models of winding angles of 15 degrees and zero is constructed, and calculate the transient thermal stress under the step temperature load. Compare the results with the theoretical results, we can find that FEM can be used to calculate the transient thermal stress response of MDCEC, which shows that the constructed finite element model is reasonable.(3) Numerical simulation of the heat shock response considering the thermal conductivity. When internal explosion occurred in a vessel, there will be a transient temperature gradient along the wall thickness direction. LS-DYNA is used to calculate the transient temperature distribution along the thickness direction, and get the transient thermal stress. Comparing the results with the transient thermal stress of DMCECV under step temperature load, it is found that when the thermal conductivity is considered, the transient thermal stress peak becomes lower. The numerical results also show that the maximum transient thermal stresses increase with the increasing of heat exchange coefficient. But it will decrease with the increase of heat capacity. Thermal conductivity has little influence on maximum transient thermal stresses. Step temperature load is a special case of considering the heat conduction when the thermal conductivity is very large.