Hironobu Yuki

An inverse method for determining material properties of a multi-layer medium by boundary element method

Abstract An optimization system, which combines a particular boundary element method and a modified Levenberg–Marqardt method, and which can be used to determine material properties of a multi-layer medium from the specified or observed displacements, is presented in this paper.

Estimation of acoustic emission source waveform of fracture using a neural network

The applicability of a neural network to acoustic emission (AE) is presented. It is shown that the shape of the simulated source waveform using piezoelectric ceramics is steplike, similar to that of mode I crack extension, and its rise-time can be varied by the resonance frequency in the thickness direction. The results imply that the simulated source can provide learning waveforms for the network. Actual AE waveforms were also acquired by conducting a tensile test of a chevron-notched graphite specimen. It was demonstrated that the appropriate source waveform associated with mode I crack extension was successfully determined by the network taught with simulated waveforms.

Design Information Modeling in 3-D CAD System for Concurrent Engineering and Its Application to Evaluation of Assemblability/Disassemblability in Conceptual Design:

In order to achieve high concurrence for product design at the stage of conceptual design, we propose four concepts for the modeling of the products in 3-D CAD system, that is, the solid model involving various kinds of design information (Design Information Solid-Model), the functional block with the design information for conceptual design, the evaluation engine for the concurrence, and the interpretation of functional block as an object/agent in knowledge processing. We made a prototype system for the evaluation of assemblability/disassemblability, as examples of the evaluation of concurrence. The prototype system is based on DIS-model, functional model and evaluation engine. It is shown that the system is very useful for product design based on the concurrent engineering.