| Earthquake occurred frequently in recent years in China, resulting in many structural deformation appeared in spherical tank, resulting in many defects. People were easy to be careless of these because these structural defects were small deformation and difficult to find. The substances storage in tank generally was flammable, explosive, poisonous, and corrosive. They could be a major hazard event of an accident, would have serious consequences. According to the above, taking Wenchuan and Ya’an gas tank experiencing the earthquake for the object, do the following work:Firstly, the tank modal test site was worked to obtain spherical tank vibration frequency and to establish ANSYS model based on the initial design drawings sphere. Based on GB12337 specification we calculated the natural frequency of the tank. We discussed three ways of spherical tank to obtain natural frequency of vibration analysis, initially determined for spherical tank. We also verified the correctness of the finite element model.Secondly, it’s a first time to measure tank defect after the earthquake sedimentation tank innovatively to obtain pillar offset variation vertical pillar and center pillar fitting tank defects. We established ANSYS finite element model including the above-mentioned defects, and took the model tank in condition analysis. We got the safe performance after the earthquake. Comparing with the results and shortcomings of defect-free tank model, we discussed the safety performance of the tank. According to the tank defects tolerance analysis, we found the maximum deformation magnitude in the existing tank, to provide a reference for the sphere of production safety.Finally, we researched the response spectrum analysis of defects and defect-free tank, respectively. So we obtained earthquake acceleration response spectrum by tank measurement modes and other seismic parameters. We obtained that defects reduced spherical tank seismic performance. |
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