A strain gauge is a widely used device that is fundamental to several measurement applications both in commercial and industrial settings. These are a key component of load cells that are used in weighing scales as well as in applications involving the monitoring of mechanical force or stress.
Simply put, it is a sensor whose electrical resistance changes in proportion to the strain being applied to it. A strain gauge can convert the force, torque, or pressure into electrical signals which can be measured and then displayed based on your specific applications.
But what exactly is this device and how does a strain gauge work? These are some questions that this blog will try to answer. So keep on reading till the end to know more about the workings of this innovative tool.
- What is a Strain Gauge?
- Basic Principle
- Working of a Strain Gauge
- Benefits of a Strain Gauge
- Applications of Strain Gauge
What is a Strain Gauge?
A strain gauge sensor is a device that changes its resistance under the application of applied stress or force. This change in resistance is converted into electric current which can be measured and then displayed on a screen.
It basically measures the deformation in an object caused by some external force like weight. A typical strain gauge consists of a zig-zag or grid-like wire or foil whose electrical resistance varies with the force that acts on it.
Basic Principle
Before we look at the principle, let’s first define a few terms. Stress refers to the force that acts on a unit area of an object. The strain on the other hand describes the displacement or deformation that occurs in an object due to the stress.
The strain gauge works on the principle of change in electrical resistance due to mechanical strain. Most weighing scales use load cells that consist of strain gauges working on the same principle.
Working of a Strain Gauge
In a typical strain gauge, a wire or foil made from copper or some other highly conductive material is connected with another flexible backing material.
The copper wire undergoes deformation(strain) when stress is applied to it which changes its cross-section area. As resistance varies with cross-section area or length, this leads to a change in this physical quantity.
This change in resistance can be estimated with the help of an external circuit like a Wheatstone bridge. Most strain gauge devices use Wheatstone bridge circuitry to determine the unknown resistance.
The Wheatstone bridge consists of four resistive arms where one is a strain gauge while the other three are fixed resistors. The application of force changes the resistance in the strain gauge. This leads to an imbalance in the Wheatstone bridge which generates an electrical output signal which corresponds to the value of the applied strain.
The measurement of the output signal gives you the magnitude of the strain. This makes a strain gauge ideal for applications like digital scales where you need to accurately measure load or stress.
Benefits of a Strain Gauge
Following are a few reasons why strain gauges are effective for the measurement of force or stress:
- These highly precise devices are not influenced by changes in temperature.
- These have a long operating life.
- Strain gauges are cheaper owing to their limited number of components as well as simplistic operation.
- Strain gauges have a very high sensitivity which makes them useful in many types of weighing scales that we see in laboratories.
- Strain gauges can work on steel, concrete, composites, and a wide range of other materials which makes them ideal in civil engineering applications.
- They can give you real-time data regarding the structural behavior of buildings during and after construction. This makes these useful in load testing as well as construction applications.
Applications of Strain Gauge
Following are some important applications of strain gauges across different industries:
- Cable Bridges
Strain gauges are used to monitor the deformation in cable bridges in real-time. This performance monitoring allows authorities to initiate preventive measures as soon as the strain gauges issue a warning which prevents fatal disasters.
- Rail Monitoring
These are used to measure stress, strain, or axial tension in rails. Strain gauges can issue warnings when the rails are not working properly which enhances safety and ensures the minimal impact on rail traffic.
- Civil Engineering
Civil engineering applications use strain gauges to measure deformations in construction materials as well as different structural elements. This ensures both safety as well as durability in every civil engineering project.
- Experimental Studies
These are used in experimental studies for material or specimen testing under different loads. This gives researchers real-time insights into different material properties like the stress distribution or future failure possibilities. This leads to the development of safer materials as well as designs.
- Geotechnical Engineering
This field uses strain gauges to measure deformation in soil or rocks. They are also used to measure the strength or deformation in tunnels, retaining walls, or other underground structures. This helps engineers predict potential failures and take the necessary preventive measures.
Conclusion
It is an extremely valuable tool in a wide range of applications including civil engineering, structural health monitoring, experimental studies, material testing, and geotechnical engineering just to name a few.
This device is a key component in most modern weighing machines that are used in industrial, commercial, as well as household applications.
Strain gauge sensors find applications in devices that are dedicated to measuring strain, weight, force, torque, pressure, stress, etc. making these an essential tool in a wide range of manufacturing, retail, as well as other industrial or commercial settings.
You can visit Accurate Meezan today to find premium quality weighing solutions for all industrial as well as personal weighing applications.
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