Micromechanics-based Method For The Tubular Condenser Analysis

In recent years, with the rapid development of the nuclear power, condenser has got more and more attentions by designers. As the main component of the condenser, the double-tube sheet has lots of tube bundles, they will lead to modeling difficulties and low computational efficiency. Therefore, a reasonable equivalent method is very important.The structure of tube sheet can be regarded as a fiber reinforced composite. Bundle is the structure of microscopic, and the tube sheet is the macroscopic aspect. So it establishes a two-scale mechanical structure. In this paper, we introduced the two-scale homogenization method which based on micromechanics, and we discussed the basic idea of equivalent and reduction method detailedly. This method was proposed to solve the problem of stress analysis and strength check in the scale-span structure. We also studied the two-scale method in dynamic response analysis. Because it's based on mean field theory, it would cause significant differences in local vibration. When the structure was strongly constrained, equivalent method for low order modal analysis could still get satisfactory results.According to the previous achievements, the applicable scope of Mori-Tanaka method which based on infinite inclusion assumption was discussed. The results show that, Mori-Tanaka method has high accuracy in thick tube sheet which the fiber volume fraction is less than 0.5.We used double-tube sheet as the application example of micromechanics in structural analysis, set up the equivalent model. In the equivalent analysis, calculated the stress and strain field of the area where no bundles drill through. And determined the dangerous area to make reduction. Integrated the results of two methods, obtained stress and displacement distribution in the double-tube sheet. At last, we did modal analysis by the equivalent method.