Stress-strain measurement is a crucial mechanical test. It is used to check whether a particular product is good for final usage. It also defines the durability of the product.  Computing strain, there are many ways one can use. People mostly use a strain gauge for stress-strain measurement. Apart from the strain gauge, other equipment used to measure strain are an extensometer, optical strain measurement techniques, etc. Before we talk more about stress-strain measurement, we should know what stress and strain are.

Stress: is the force per unit area generated within the materials due to externally applied forces.

Strain: The strain is the amount of distortion experienced by the body in the direction of force application divided by the body’s original dimension.

Reason For Strain Measurement

Measurement of strain is to determine the level of stress on the material. The measurement of strain specified the absolute value and direction of the mechanical stress. Using Hooke’s law, all these calculations are based. Hooke’s law determines the direct Hooke’s proportionality of the strain and the stress of a specific material using its elasticity.

How Is Stress-Strain Measured?

First, one must understand the effects of strain on the material to understand how stress-strain can be measured. Usually, strain is a non-dimensional value representing the change in a material’s size relative to its initial size. The standard fractional prefixes of the SI system are used as the length change is very small. A micrometer per meter is generally used for strain. Different types of gauges and sensors can be used for stress-strain measurement. The most common device used is a strain gauge.

What Is A Strain Gauge?

To calculate strain on an object, the equipment strain gauge is used. If an external force is assigned to an object, deformation occurs in the object’s shape. It is called a strain, and it is both comprehensive and tensile. If the object deforms with the limit of elasticity, it becomes narrower and longer or shorter and broadens.

There is a change in resistance from end to end. Minor changes occur in the geometry of an object, and the strain is sensitive to that. The amount of induced stress can be calculated by measuring the change in the resistance of an object.

What Is Measured By The Strain Gauge?

When discussing strain gauges, the first thing to understand is what they measure. A stress-strain measurement equipment strain gauge is a sensor whose measured electrical resistance varies with changes in strain.

Load cells are designed to do stress through beam elements where strain gauges are located. With a strain gauge, the applied force, pressure, and torque are changed into an electrical signal which can be measured. When forces cause strain, it is then measured with the strain gauge by changing electrical resistance.

What Is The Importance Of Strain Gauge In Stress-Strain Measurement?

Tensile forces not susceptible to compression are applied to the beams and columns that make up structural components. The structures are distorted due to those forces, but there is a limit to the amount of stress they can tolerate. Following that, the structural components will become ineffective.

The application of field stress causes structures to deform, while the application of ultimate tensile stress causes structures to the neck. To ensure the structural integrity of these buildings, we need to determine the maximum amount that the material can stretch.

Although we cannot measure stress directly, we can measure the strain that a component is under, which allows us to compute stress indirectly.

Some components are highly stressed and can also be critical components of large structures. So, it is crucial for stress analysis of these kinds of elements. We have to use developed and highly advanced measuring techniques to get highly accurate values. Extensometer can also be used to analyze the stress-strain measurement.

An extensometer is used to measure changes in an object’s size. This device is helpful for stress-strain measurement as well as tensile tests. The geometric moir√© method is another process used to measure displacement yields, either in-plane or out-of-place. Using this technique, one can develop the specimen’s strain under tension or compression.


For Stress-strain measurement, strain gauges are versatile geotechnical tools with broad applications. It helps to ensure safety and productivity. I hope this blog helps you with a better understanding of stress-strain measurement.