Strain Measurement on Stiff Structures – Experimental Evaluation of Three Integrated Measurement Principles

This paper presents an experimental evaluation of three different strain measuring principles. Mounted on a beam resembling a car engine foundation, metal foil strain gauges, piezoresistive silicon strain gauges and piezoelectric patches are used to measure structure-borne forces to control an active mounting structure. FEM-simulation determines strains to be measured in the range of 10-8 … 10-5 m/m. These low strains cannot be measured with conventional metal foil strain gauges, as shown in the experiment conducted. Both piezoresistive gauges and piezoelectric patches show good results compared to a conventional piezoelectric force sensor. Depending on bandwidth, over-load capacity and primary electronic costs these principles seem to be worth considering in an adaptronic system design. These parameters are described in detail for the principles investigated