Analysis Method For Perforated Structure Strength

Perforated structure is widely used in the components of aeroengine. This kind of structure istoo complicated to be solved by elastic mechanics, and it is hard to mesh suitably while applyingfinite element method which lead to inefficiency. In that case, these methods are not applicableduring engineering design stage. In this paper, researches on strength analysis of aeroengine per-forated structure were conducted, and equivalent stiffness prediction and strength analysis me-thods were acquired via a series of finite element simulation, mechanical formula derivation andexperimental study. The main researches of this thesis includes:Perforated structures were equivalent to solid structures with equivalent stiffness, and theequivalent stiffness was predicted by finite element analysis applied to a representative volumeelement under periodical boundary conditions according to homogenization theory. Furthermore,semi-empirical formulas for predicting the equivalent stiffness were acquired by mechanics ofcomposites considering the similarity of perforated structures and composites. The result of theseformulas and former prediction made good agreement.The method for in-plane strength analysis of perforated plates was established. The stressconcentration factors at the edge of the hole of perforated structures were obtained by finite ele-ment analysis applied to a representative volume element under periodical boundary conditions.Based on the maximum stress theory for orthotropic materials, formulas for predicting equivalentstrength of perforated plates were established by using the relationship between equivalentstrength and stress concentration factors.Experimental study was undertook to perforated structures. The equivalent stiffness andequivalent yield strength of perforated specimens which were made of steel were obtained by un-iaxial tensile test. And the strain field distribution and trends of specimens were acquired by digi-tal image correlation. The test result made good agreement with the prediction of equivalent stiff-ness and equivalent yield strength of perforated plates via the methods proposed in this thesis.