Prediction of Macroscopic and Local Stress-Strain Behavior of Perforated Plates under Primary and Secondary Creep Conditions.

Abstract

Prediction methods of macroscopic and local creep behavior of perforated plates are examined in order to apply these methods to the structural design of perforated structures such as heat exchangers used in elevated temperatures. Both primary and secondary creep are considered for predicting macroscopic and local creep behavior of perforated plates which are made of actual structural materials. Both uniaxial and multiaxial loading of perforated plates are taken into consideration. The concept of effective stress is applied to the predication of macroscopic creep behavior of perforated plates, and the predicted results are compared with the numerical results by FEM for the unit section of perforated plates under creep, in order to confirm the propriety of the proposed method. Based on the idea that stress exponents in creep equations govern the stress distribution of perforated plates, a modified Neuber's rule is used for predicting local stress and strain concentrations. The propriety of this prediction method is shown through a comparison of the prediction with both the numerical results by FEM for the unit section of perforated plates under creep, and experimental results by the Moire method.