An extensometer is a highly precise mechanical or electronic instrument employed for the measurement and quantification of dimensional alterations in materials subjected to mechanical stresses, encompassing tensile, compressive, or flexural forces. This instrumental apparatus typically integrates specialized sensors or strain gauges, meticulously calibrated to detect and record even the minutest variations in a material’s length or deformation. Extensometers are indispensable tools in materials testing, structural analysis, and mechanical properties assessment, furnishing engineers and researchers with invaluable insights into parameters such as:
Optical extensometers, also known as Non-Contact extensometers, are a specialized subset of Epsilon extensometers, leverage advanced optical principles for precise deformation measurements in materials. These instruments are particularly valuable in situations where conventional resistance strain gauges face challenges, such as environmental constraints or irregular specimen shapes.
Operating on the basis of light and optical sensors, optical extensometers typically incorporate a light source (e.g., laser) and a light detector (e.g., photodetector or camera). As the material undergoes deformation, changes in surface attributes—reflectivity, transparency, or the light path—are triggered. The optical extensometer quantifies these alterations, providing accurate deformation measurements. This optical approach proves advantageous in environments with high temperatures, harsh conditions, or unconventional specimen shapes, where traditional electrical strain gauges may be impractical.
Contact extensometers are another type of Epsilon extensometers used to measure the deformation or elongation of a material under stress or strain. They work by employing a component called “strain gauge”, which is typically a thin wire or a slender strip made of resistive material. These strain gauges are attached to the material being tested.
When the material experiences stress or strain, it undergoes deformation or elongation. This deformation causes the strain gauge to also change its shape, and as a result, its electrical resistance changes in a proportional manner to the deformation. This change in electrical resistance is what allows contact extensometers to make precise measurements of the material’s deformation.
Contact extensometers are valuable tools in materials testing, quality control, and research, as they provide precise data on how materials behave under different levels of stress and strain, helping engineers and scientists understand their mechanical properties.
Epsilon extensometers offer compelling advantages for various applications:
