What is Strain Gauge: Working, Principle & Diagram.

What is Strain Gauge.

A strain gauge is a sensor that measures the strain or deformation of an object or material. It is a device that converts mechanical displacement or deformation into an electrical signal. A strain gauge is typically made up of a thin wire or foil that is attached to a material or object that is being measured.

When the material is subjected to stress or strain, the wire or foil is also deformed, causing its resistance to change. This change in resistance is measured and used to determine the amount of strain or deformation that the material is experiencing.
Strain gauges are used in a wide range of applications, including load cells, pressure sensors, and force sensors. They are commonly used in mechanical engineering and materials science to measure the deformation and stress of structures, as well as in manufacturing and quality control to ensure product reliability and consistency.

Working process of Strain gauge:

The working process of a strain gauge can be broken down into the following steps:

1. Bonding: The strain gauge is bonded to the surface of the object being measured using an adhesive material. The gauge is usually bonded in a way that its length is aligned with the direction of the strain being measured.

2. Application of Stress: When the object is subjected to stress or strain, the gauge experiences a corresponding deformation, which causes a change in its electrical resistance.

3. Wheatstone Bridge Circuit: The strain gauge is connected to a Wheatstone bridge circuit, which is used to measure the change in its resistance. The Wheatstone bridge consists of four resistors, including the strain gauge, which is one of the resistors in the circuit.

4. Voltage Supply: A voltage supply is applied to the Wheatstone bridge circuit, which causes a current to flow through the circuit. The voltage drop across the strain gauge, which is proportional to the strain being measured, is measured by the Wheatstone bridge circuit.

5. Signal Conditioning: The output signal from the Wheatstone bridge circuit is amplified and filtered to remove any noise or interference that may be present. The signal is then conditioned to provide a readable value of the strain or deformation being measured.

6. Readout: The conditioned signal is then converted into a digital or analog value, which can be displayed on a monitor or recorded for further analysis.

Usage of Strain Gauge:

Some of the common applications of strain gauges are:

1. Structural engineering.

2. Aerospace engineering.

3. Automotive engineering.

4. Medical devices.

5. Robotics.

1. Structural engineering: Strain gauges are used in the construction of buildings, bridges, and other structures to monitor their structural integrity and detect any deformations or movements that may indicate potential failure.

2. Aerospace engineering: Strain gauges are used in the design and testing of aircraft and spacecraft structures, engines, and other components to measure their deformation and stress levels under different conditions.

3. Automotive engineering: Strain gauges are used to measure the deformation and stress levels of car components such as suspension systems, chassis, and tires, to ensure their reliability and performance.

4. Medical devices: Strain gauges are used in medical devices such as prosthetics and orthotics to measure the deformation and stress levels of the devices and ensure their proper fit and function.

5. Robotics: Strain gauges are used in robotics to measure the deformation and stress levels of robotic arms, legs, and other components, to ensure their proper function and avoid damage or failure.

Principle of Strain Gauge:

The following are some of the characteristics of a strain gauge:

1. Sensitivity.

2. Accuracy.

3. Linearity.

4. Temperature sensitivity.

5. Hysteresis.

7. Durability.

8. Cost-effectiveness.

9. Non-intrusive.

1. Sensitivity: A strain gauge is highly sensitive and can detect even small amounts of strain.

2. Accuracy: Strain gauges are highly accurate and have a low level of error. However, the accuracy of the gauge depends on the quality of the material and the calibration procedure.

3. Linearity: Strain gauges have a linear response over a wide range of strains.

4. Temperature sensitivity: Strain gauges are sensitive to temperature changes, and the resistance of the gauge changes with temperature.

5. Hysteresis: Strain gauges exhibit hysteresis, which means that the output of the gauge depends on the history of the strain.

6. Durability: Strain gauges are durable and can withstand harsh environments.

7. Cost-effectiveness: Strain gauges are relatively inexpensive compared to other types of sensors.

8. Non-intrusive: Strain gauges can be attached to the surface of an object, making them a non-intrusive measurement method.

How is strain measure:

Depending on the type of material and the precision required.

• One common method to measure strain is using strain gauges. These are devices that are attached to the surface of a material and measure the changes in the material's length or shape. The strain gauge is made up of a wire or a thin film of a conductive material that changes its resistance as it is stretched or compressed. The change in resistance is proportional to the amount of strain experienced by the material, allowing the strain to be calculated.

• Another method for measuring strain is by using an extensometer. An extensometer is a device that clamps onto the material being tested and measures the change in length between two points on the surface of the material. This method is typically used in laboratory settings, where high precision measurements are required.

• Finally, strain can also be measured using visual methods, such as by using a ruler or a grid pattern that is placed on the surface of the material being tested. The deformation of the material can be observed by comparing the original grid or ruler pattern to the deformed pattern after applying stress. However, this method is less precise than the other methods mentioned above.