The objective of this research is to develop electronic interface circuits to measure strain in automobile machine elements with a silicon micromachined resonant sensor. The strain sensor is required to have a resolution of 0.1 microstrain over a range of +/- 1000 microstrain and a measurement bandwidth of 10kHz. The dimensions of the strained areas in the bearings are on the order of 100-200 microns and therefore gauge lengths of the strain sensor must be in this range. The smallest commercially available strain sensors have gauge lengths of around 1mm are too large and thus micro-machined strain gauges are an attractive solution to this problem. Double-ended tuning fork (DETF) resonant sensors are a natural choice for this application because they have the potential to meet the size, resolution, and bandwidth requirements described above. When subjected to an axial strain, the DETF's length changes resulting in a change in its resonant frequency and or period. Our research will concentrate on the methods of measuring the change in resonant frequency and therefore strain.
Project end date: 08/26/05