Dynamic Strain and Crack Monitoring Sensor

Los Gatos Research proposes to develop a new automated vehicle health monitoring sensor system capable of measuring loads and detecting crack, corrosion, and disbonding in advanced aerospace structures using a novel lock-in laser interrogation technique combined with a Bragg grating array (BGA) technology for strain and guided Lamb wave (GLW) sensing. Los Gatos Research's novel sensor instrumentation offers a number of advantages including sensor compactness (0.2mm x 0.2mm x 10mm), lightweight (few grams), remote data acquisition capability, low-cost, and low power consumption. The inherently reliable lock-in laser demodulation technique permit simultaneous measurements of strain, temperature, and acoustic fields with high resolution and high sensitivity. In Phase I, we have demonstrated feasibility by building a prototype instrument capable of measuring static and dynamic strain, temperature, and ultrasonic waves using a lock-in laser demodulation technique and a fiber Bragg grating array sensor network. In Phase II, LGR will deliver to NASA a rugged, compact, multi-channel instrument optimized for vehicle health monitoring studies including strain, temperature, and crack monitoring with high precision, high resolution, and high sensitivity. This dedicated prototype will include an integrated microcontroller, operate unattended, and address the power and stability requirements unique to in-flight studies.