Principles of Material Structural Change Informatics to Characterize and Evaluate Damage of Materials in Service

Abstract

We present the principles and fundamentals of material structural change (MSC) informatics in this paper. MSC informatics involves data-enabled endeavors to make decisions of material behavior based on the past and present MSC event data. The data are the acquired events of material structural changes, which are measurable using a multitude of techniques, one of which is acoustic emission. The informatics of material structural changes are invaluable and serve as a practical tool to monitor the structural health in both civil and mechanical infrastructures and for prediction of remaining service life. To obtain MSC informatics, there are two major phases involved: acquisition of material structural change events and implementation of informatics. Active and passive means are the two primary techniques to acquire MSC events of materials in service. The fundamentals of MSC informatics include (1) the 3S principle, (2) establishment of a digital multivariate D matrix to represent MSC and its properties, and (3) the basic operations of MSC informatics. Using MSC events acquired by acoustic emission as examples, we show that the digital multivariate D is indeed capable of categorizing MSC event mechanisms when correlation analysis and principal component analysis were conducted. Further, we were able to utilize statistical ensembles to describe the material damage state in terms of information entropy as the evolution of MSC occurred. Information entropy is a scalar quantity and is a promising indicator of damage event ensemble advancement and as such, an important part of MSC informatics. We have also illustrated that the principle of maximum entropy and analysis of time series are promising areas for advancement of MSC informatics.

Natural frequency measurement of steel components by the sound signal

“…[3][4][5] In the meantime, the natural frequency will change when the boundary condition of the structural component is changed. [6][7][8][9] Moreover, the natural frequency can also reflect the change of the axial internal force in a structural component such as a cable or a truss bar. [10][11][12] Thus, the test method of the natural frequency has received much attention in recent years.…”