Passive Stress Sensing Using Raman Piezo-Spectroscopy

The objective of this study is to develop a method to measure stress in a structural member using the Raman Piezo-spectroscopy (RPS) as passive sensors. RPS is a matured non-destructive spectroscopy technology widely used in material science and aerospace engineering to measure stress in various substances. The method uses RPS to provide an innovative solution for stress measurement without supplying external power and installing delicate electronic circuits in field conditions. The RPS system consists of the RPS reader and target. The target can be commercially manufactured with Raman-sensitive metal oxides (e.g., α-Al2O3). In the target manufacture, sputtered metal oxides at a high temperature are solidified with a hot isostatic press. Therefore, the target can be used as a passive sensor that does not require external power supply and additional electronic circuits. The RPS reader is a noncontact Raman spectrometer that shoots a low-powered laser beam on the target surface and analyzes the fluorescence beam. This paper will discuss the novel concept of the Raman-based stress sensing and some preliminary testing results