Numerical Simulation Of Tank Containers Under The Rail Impact Testing By The Fluid-Structure Interaction Method

Under rail transport conditions, tank containers are usually suffered from external and internal impacts, which will cause the plastic deformation of structures. It is a certain security risk for the normal application. Nowadays, the load-ability of the impacts has become one of the most important criterions for tank design and manufacture. The research was supported by a cooperative project (strain hardening of austenitic stainless steel cryogenic tank) conducted by Zhejiang University and Nantong CIMC Tank Equipment Co. Ltd., which is the largest tank manufacturer in China. According to the requirement of ISO1495-3 2006:Testing of the External Restraint (Longitudinal) Dynamic and nonlinear FEM method, the rail impact testing simulation for tank containers was carried out by considering complex fluid-structure interaction, structural dynamics and the characteristic of stress-strain relationship.Firstly, the prototype testing for data accumulation was fully assimilated to summarize the corresponding guiding principles for standard formulation, which provided a solid theoretical and experimental basis.Secondly, appropriate numerical algorithms were adopted. Two models, the gravity model and the simple impact model, were proposed to verify if the combinational algorithms can reflect the true physical phenomenon. The simulation results were compared with existing analytical solutions and experimental data.Thirdly, based on the solution of the testing simulation, a model of 40-ft cryogenic tank container was built. Details of the entire simulation process, including the model simplifications, mechanical properties, constitutive equations, computational loads and boundary conditions, were described and explained.Finally, according to the ISO standard, dynamic analysis and curve verification of the simulation results were completed. The effects of fluid-structure interaction to the structure and the flow inside were analyzed. Meanwhile, comparative study of stress variation in time-domain for each component was performed.According to the results, plastic deformation, which may cause the failure of the product, did not occur under the condition of the impact testing regulated by ISO1946-3. However, it is find that serious stress concentration occurred around local region of baffles. Thus, in this paper, in order to conducting experiments and the improvement, the influence of baffles was investigated.The simulation method and results proposed in this paper can be further applied to guide the design and improve performance of tank containers, which has certain study value and prospects in practical applications.