Yuan Mei

Research to real-time algorithm of crack initiation monitoring based on Welch's method

In recent decades, the FBG (Fiber Bragg Grating) sensors are widely used in SHM (Structural Health Monitoring) fields for the characteristics of its simple structure, tiny volume, light weight, anti-corrosion, and anti-electromagnetic interference. However, there are two defects that limit its application in some fields. Firstly, the low sampling frequency due to the induction principle provides a big challenge to the solver algorithm. Secondly, real-time online monitoring which requires quick and efficient signal processing for the long time series is the development direction of SHM and also needs progress in the fast solver algorithm. For these two reasons, we propose a novel method based on the PSD (Power Spectrum Density) to analyze the sampled data from FBG sensors in this paper and it is applied in an online crack initiation monitoring system and obtain some satisfactory results. A comparison with the preliminary research indicates the accuracy and rapidity of the proposed algorithm and points out the applicability in the real-time online monitoring system for crack initiation.

Study on SOBI Separation Method for Composite Materials Simulated Damage AE Signals

This paper introduces an improved de-noising SOBI (Second Order Blind Identification) separation method, which is used to separate mixed components of different composite materials damage acoustic emission simulated signals. The contrastive analysis and numerical simulations of a variety of blind source separation algorithms are investigated, which suggests that traditional SOBI performance degrades when noise is present. By introducing noise-elimination algorithms, SOBI is improved and optimized. The improvement of separation effect of the de-noising SOBI algorithm is proved by numerical simulation experiments. Finally, based on the online structural damage simulation and monitoring test-bed, the feasibility of the proposed method is validated.

ATS Software Framework Design Pattern and Application

Framework is a way of reusing the design of whole system or part of it, which is considered as the most effective way now in software engineering. The trend of automatic test system (ATS) software is becoming more and more complex. In response to this trend and to improve the efficiency of its software development, combined with the technology related to software engineering and automatic test technology, this paper presents a pattern of developing software framework for the ATS, which is independent of the hardware system. By the instance of building the CAN test system software framework, it has proved that this pattern works well. The proposed method can help developers to build domain software framework quickly, to cut down the development cycle greatly, and to reduce the development cost obviously.

Design and Implementation of Damage Simulation Structural Health Monitoring Test-Bed

An online structural damage simulation and monitoring test-bed is introduced, it can provide experimental data for signal processing and feature extraction algorithm. By analyzing features of structural damage and acoustic emission (AE) signals of carbon fiber reinforced composite (CFRP), different kinds of CFRP damage AE signals numerical models are constructed. The PZT actuator array can generate Lamb waves and simulate AE waves. Then the active or passive damage signals are acquired by sensor array. In addition, a set of supporting software based on Lab VIEW and MATLAB is provided to help damage monitoring and signal processing. Software platform has well-designed human-machine interface and can drive hardware to generate and acquire sampling signals. Also, it can store sampling data and analysis signals with built-in algorithms for signal processing and damage feature extracting. Then a series of experiments are carried out on the pre-built SHM test-bed. The results suggest that models are correct and system is efficient in simulating structural damage signals.