Tension testing machine fixture selection

The determination of the fixture is difficult to define, because of the particularity of the fixture structure, for a fixture, sometimes it is difficult to determine it is more suitable for the kind of sample, usually from the following three points to judge:

1. Whether the fixture is convenient and safe to use.

2. whether the clamping is reliable, there can be no slipping phenomenon.

3. during the test, the sample break point is good. The data discreteness is small. (i.e. the specimen is continuously clamped, inside the clamps, parallel segments or outside the standard distance)

There are several types of materials that are special to their own characteristics and applicable environments, and so far, there are not many solutions.

1, steel wire, steel strand due to the high hardness of the sample, the internal structure is relatively loose, the force in the tensile test process is not uniform, the clamp holding the sample is easy to wear and other reasons, the fixture has not been a good solution. In the past, aluminum foil was used to do it, and four pieces of aluminum foil were spent on a test, which was too much waste. Now the tension testing machine jig sprayed with emery is used, the slip problem is solved, but the fracture position is always not ideal, and the success rate of 10 samples is only 50%.

2, for the deformation of large amount of material due to deformation is too large, so it is difficult to clamp, the design of the fixture is also a difficult point.

3, for the need to do the test in a high-temperature environment, the requirements of the fixture is also very high, both high-temperature resistance, but also do not deform, the volume should be small, so the general test machine manufacturers, it is also a very difficult thing.

4, for large batches, high-frequency tests, foreign countries generally use fully automatic clamping, and domestic manufacturers of testing machines, or a new subject.

5, and finished products and semi-finished products testing, the need for fixtures is a variety of fixtures, how to personalize to meet customer requirements, for all test machine manufacturers, is a challenge.