Elastic and inelastic finite element analysis of cylindrical shell intersections.

摘要

Cylindrical shell intersections are very common structural components in many industries, such as transportation, nuclear and power engineering, chemical and petro-chemical, aerospace, construction, etc.;Cylindrical shell intersections under various load conditions can be analyzed using two different material behavior characterizations: linear elastic analysis and elastic-plastic analysis. Linear elastic analysis focuses mainly on the determination of the stress concentration in the intersection area and on the flexibility before the structure experiences plastic behavior. Limit load and burst pressure analyses are two of the failure modes that can be investigated through the use of elastic-plastic stress analysis. The objective of this thesis is to systematically investigate the cylindrical shell intersection problem from the linear elastic analysis to elastic-plastic analysis by use of finite element analysis (FEA). Experimental data serve as the benchmarks.;Since the accuracy of the FEA model has an influence on the quality of the solution, an example of how to set up an accurate FEA model for the analysis of cylindrical shell intersections is illustrated by studying the stresses in the neighborhood of a particular cylindrical shell intersection when it is subjected to internal pressure and external moments. Finite element models, based on these FEA modeling guidelines and which are generated using three-dimensional isoparametric solid elements, are employed to study the stress concentration in the vicinity of the intersection and the flexibility of shell intersections in the linear elastic region. Limit loads and burst pressure of various intersections are further investigated using an elastic-plastic characterization. In addition, the influence of geometric parameters (diameter ratio, thickness ratio and diameter to thickness ratio) on stress indices, flexibility factors, limit loads and burst pressures are examined. On the basis of the agreement between the experimental data and properly modeled FEA results, it can be concluded that finite element simulations can be employed with sufficient accuracy to study various behaviors associated with cylindrical shell intersection structures.