Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : March 17, 2018 - March 18, 2018
Usually, it is difficult to calculate 3D strain distribution for a kneaded clay block. Of course, if the block surface is covered with some kinds of patterns, images or marks, we may determine whole strain distributions easily. Without them however, it is difficult to correlate a particular point of the deformed clay with a corresponding point of a clay before deformation. When we try to evaluate inelastic strain distribution for gas turbine blades after some operation non-destructively, the same kind of difficulty arises. In this research, a new method to obtain the three - dimensional distribution of inelastic strains is proposed by applying the inverse problem using the FEM analysis. Here inelastic strains derived from the eigen-strain theory are evaluated by comparing two contour shapes of before and after the operation that are captured using a 3D contour scanning technique. In the problems treated here, we can correlate in advance only a few particular points such as blade corners. Then, we introduced “virtual nodes” to define “displacement (not deformation)” at any locations other than the well-defined corners. It validity is checked by using multiple numerical simulations. It was found that the inelastic strain distribution generated in turbine blades can be mostly reproduced by the proposed method. Moreover, it was found that the estimation accuracy is improved by introducing iterative calculation.
