A system approach for temperature dependency of impedance-based structural health monitoring

Abstract

An impedance-based structural health monitoring (SHM) system employs a piezoelectric patch to excite the structure under test and capture its response. Impedance-based SHM offers several advantages over other methods such as good performance for local damage detection and simple hardware. A major problem for impedance-based SHM is temperature dependency. Specifically, baseline impedance profiles of structures vary as the ambient temperature changes. In this paper, we propose a new method to compensate the effect of temperature on baseline profiles. Our method is to select a small subset of baseline profiles for some critical temperatures and estimates the baseline profile for a given ambient temperature through interpolation. We incorporated our method into our SHM system and investigated the effectiveness of our method. Our experimental results show that (i) our method reduces the number of baseline profiles to be stored, and (ii) estimates the baseline profile of a give temperature accurately.