The extensometer is an instrument for measuring the linear deformation between two points of components and other objects. It is usually composed of sensors, amplifiers and recorders. Many people in use react that the extensometer is not clamped tightly, whether there is a quality problem, in fact, it is not the quality problem of the extensometer, but the problem of the method of use.
When clamping and extending, the extensometer is gently picked up, the spacer of the benchmark bar is clamped between the force arm and the benchmark bar, and the two force arms are pressed so that the two blades contact the sample vertically. The extensometer is tied to the sample with a spring or rubber band, and the spacer of the benchmark bar is taken out after loading, so that the gap between the force arm and the benchmark bar is kept at 0.5mm.
Matters needing attention:
1. The electronic universal testing machine must be checked before the test, so as not to cause damage to the extensometer.
2. To protect the electronic extensometer, do not fall and keep the knife edge sharp.
3. Do not remove the screw at both ends of the benchmark rod to prevent the opening of the arms from opening indefinitely, resulting in permanent deformation of strain gauges and spring sheets, which may damage the extensometer.
It is worth mentioning that some fixtures of electronic universal testing machine will produce an initial force when clamping the sample, so remember that the initial force must be eliminated before clamping the extensometer, so that the distance held by the extensometer is the original distance of the sample in its own state.