Signal Processing System for Guided Wave-Based SHM Technique

Abstract

Reported research is focused on practical realization of guided wave-based SHM. Miniaturization of a SHM system could be very interesting in the scope of real life application. Embedded solution allow to minimize the dimensions of the whole system replacing a PC computer for signal processing. In this research damage localization system was developed. Damage localization process is based on elastic wave propagation method. Embedded system was realized on Field Programmable Gate Array FPGA in which system on programmable chip (SoPC) was implemented. Damage localization algorithm was coded in C++ and implemented in this system. Elastic waves were generated and received using dedicated device. Gathered signals representing elastic waves propagating in structures were sent to embedded damage localization system in order to extract damage location. The aim of developed damage localization algorithm is to create colour map that indicates places of elastic waves reflections. Wave reflections are caused by all kind of discontinuities existing in the monitored structures like: boundaries, transducers and most important – damage. In the first approach this algorithm was coded in MATLAB® environment. This software allow to very fast coding of developed algorithms because of large number of functions and libraries included in MATLAB®. The huge disadvantage of this environment is the long time of calculation if we compare it with the code developed in C++. Second thing is a price connected with MATLAB® purchase. In this purpose MATLAB® script code was converted to C++ code with graphic user interface GUI working under the PC with Windows operating system in order to verify the results. In next step C++ software was developed in order to embedded it in post processing unit. Thanks to this the result of damage localisation is displayed on the LCD display of the system. The reported research led to development of an embedded system for signal processing in SHM applications.