Conformal Strain Gage System for the Measurement of Stress in Helicopter Transmission Gears

We propose a conformal strain gage array to provide an improved strain measurement technology for turbomachinery and mechanical components. The array consists of MEMS sensors and electronics embedded in a flexible, compliant substrate which may be conformally applied to test components. The flexible strain gage array will allow multiple integrated strain gages, as well as interface electronics and wireless data transmission, to be incorporated in a single part which can be conveniently installed on a test article, such as a turbine blade or transmission gear. The technology proposed herein will greatly simplify strain gage installation, reducing cost and improving reliability in component testing. On-board integrated electronics will improve preformance by providing amplification and signal conditioning. The use of slip rings can be elininated through wireless data transmission. In addition to strain measurements, the technology we propose may be applied to other measurements, such as temperature, vibration, pressure, and surface shear. The proposed technology will provide broad, new capabilities in test and analysis, allowing a greater amount of data to be collected with improved accuracy, reliability, and ease of use, and reduced cost through batch fabrication and simplified installation. The conformal strain gage array has broad applications in analysis of many types of engineered structures. Strain gage technology has large, established markets in which the proposed technology will provide new capabilities. Applications include analysis of automotive parts, aerospace components, medical devices, and industrial machinery. The wireless data transmission feature will be used in remote locations for structural health monitoring and condition based maintenance. The gages could be installed in airframes, bridges, or buildings, for active structural control or to identify potential failures.