Resistive Strain Measurement Devices

Abstract

The measurement of strain is a fundamental necessity in many engineering disciplines and related industries. Methods of measurement can be roughly grouped into two major categories: those based on the behavior of light and those based on electronic devices. The present Chapter discusses strain within the framework of continuum mechanics. The study finds that strain is essentially a description of the deformations that have occurred at a point in a solid body. Many different factors have been noticed that may cause deformation. A normal strain corresponding to an increase in length is called a tensile strain and is algebraically positive. Conversely, a normal strain corresponding to a decrease in length is called a compressive strain and is algebraically negative. The description of the deformation that is the strain, can be rotated from one coordinate system to another using the strain transformation equations. All the practical implications have been discussed comprehensively. Nowadays, the most widely used strain measurement device is certainly the resistance metal strain gage and are based on a phenomenon known as the piezoresistive effect. Various perspectives for the techniques such as Wheatstone bridge and liquid metal strain gages have been discussed comprehensively.