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The Secret of Deformation and Resistance: How Do Strain Gauges Precisely Measure Strain?
Strain gauge, or strain sensor, is a device that accurately measures the deformation of an object. Based on the understanding of the physical properties of electrical resistance and its shape dependence, the invention of the strain gauge revolutionized the fields of materials science and engineering. In this era of continuous technological advancement, the development history and application scope of strain gauges continue to expand. How they affect our design and engineering practices has become a new hot topic.
Basic principles of strain gauges
The basic working principle of a strain gauge is very simple. When a conductive material is stretched or compressed, its shape and size change, and the resulting change in electrical resistance. In this case, the strain gauge senses this change through a conductive coil bonded to the object. The degree of change in resistance is proportional to the pressure or stress exerted on the object. This ratio is often called G.F. or gauge factor.
Strain gauges were independently invented in 1938 by Edward E. Simmons and Arthur C. Ruge, originally inspired by studies of the behavior of metallic materials under impact loading.
Historical background
The origins of strain gauges can be traced back to the 1930s. Simmons, a researcher at the time, conducted in-depth research on the stress-strain behavior of materials and proposed a new measurement method. Professor Ruge's research focuses on seismology. He also encountered the challenge of measuring small-scale models, and finally independently developed strain gauge technology. The evolution of this design not only pioneered the detection of strain, but also stimulated subsequent industrial applications.
Function and performance
Strain gauges usually consist of an insulating elastic base material and a supporting metal foil-shaped pattern. When the connected object deforms, its change in resistance can be accurately measured. This process usually involves reading the signal with the help of a Wheatstone bridge configuration. The size and design of strain gauges will vary for different application needs, and the requirements for strain gauges for long-term stability and dynamic experiments are quite different.
Strain gauges are used in a wide range of applications, from structural health monitoring to aerospace engineering and even biological measurement, all demonstrating their usefulness in different fields.
Application scope
Today, strain gauges are widely used in many fields. Here are some of the main application areas:
- Structural health monitoring: Can be used to detect fatigue and damage on bridges and other structures.
- Biometrics: Measure human skin strain to analyze posture, joint movements, etc.
- Predictive maintenance: The strain changes of materials can be monitored to predict the timing of repair or replacement of components.
- Aeronautical engineering: Precisely measure the structural loads and wing deformations of aircraft.
Temperature impact and compensation
Temperature change is a factor that cannot be ignored as it can have a significant impact on strain gauge performance. Different materials have different thermal expansion rates, so it is important to choose the appropriate alloy to achieve self-temperature compensation. In general, high-quality surface preparation and the use of appropriate adhesives can reduce the influence of the external environment on the measurement results.
Challenges and future prospects
With the ever-changing demands and rapid development of technology, strain gauges face various challenges, such as energy consumption, stability and accuracy. However, continued advances in technology, especially in the development of non-contact measurement techniques, open up space for future applications.
For example, the emergence of fiber optic sensors allows us to perform precise measurements over long distances while maintaining low energy consumption. This not only improves the reliability of sensing, but also opens up new application areas. As more new materials and methods become available, the application potential of strain gauges will undoubtedly be further expanded. Of course, this also makes us rethink a question: With the rapid development of technology, how will strain gauges meet more complex measurement needs in the future?
