Tensometry

Tensometry is the science and practice of measuring tensile forces, stresses, and strains in materials and structures. It involves the development and use of sensors and techniques to quantify deformation and related mechanical quantities.

Core concepts involve attaching a sensor to or near a test specimen and inferring strain or stress from a measurable signal. Common signals arise from changes in electrical resistance, light, or displacement. Method choice depends on required sensitivity, environment, and strain range.

Electrical resistance strain gauges are widely used. A foil or semiconductor gauge is bonded to a surface; as the material deforms, the gauge resistance changes and is read in a Wheatstone bridge. Calibration, temperature compensation, and gauge factor are important considerations.

Mechanical extensometers measure end-to-end displacement directly, using contact pins or non-contact optical methods.

Optical tensometry includes digital image correlation and interferometric methods, which measure full-field strain by tracking surface patterns or interference fringes.

Fiber optic tensometry uses sensors such as fiber Bragg gratings or interferometric fibers, offering advantages in high temperature, harsh environments, or remote sensing.

Applications include materials testing, structural health monitoring, aerospace, civil engineering, biomechanics, and geotechnical research. Tensometry supports characterizing material properties, validating simulations, and monitoring loads in service.

The field matured in the 20th century with the invention of electrical resistance strain gauges in the 1930s and has since expanded to optical and fiber-optic techniques.