Using Strain Gages to Measure Axial Force

Using strain gages for purposes other than measuring in engineering units of strain is very common.  In fact, the question is often asked, "How do I wire strain gages in a full-bridge so that I can measure axial force?"  The following illustration addresses that question.  This arrangement is known as a Full-Poisson Bridge, and is sensitive to axial forces.  On the component shown, this bridge arrangement will have very little output due to torsional and bending forces.

P- is negative excitation voltage

P+ is positive excitation voltage

S- is negative signal out

S+ is positive signal out

Output will be positive due to tensile loading, and negative due to compressive loading.

The best accuracy is obtained by applying a known-load to the component, and equating the bridge output to that known load at several load points.

For most applications of this type, 0°-90° Tee Rosettes are available for immediate shipment from Micro-Measurements Super Stock.

For more information about the use of strain gages for force measurement, contact a Micro-Measurements Applications Engineer, Technical Sales Manager, or independent Sales Representative at mm@vpgsensors.com.