Due to the special structure of the testing machine fixture, it is sometimes difficult to determine which type of specimen is more suitable for a fixture. Usually, we judge it from the following three points:

1. Is the fixture easy and safe to use.

2. Whether the clamping is reliable and there should be no slipping phenomenon.

3. During the experiment, the breakpoint of the sample was good. The data has low dispersion. There are several types of materials that have their own characteristics and specific applicable environments, such as samples that are continuously clamped, clamped, parallel, or outside the gauge length. So far, there are not many solutions available

4. Due to the high hardness of the specimens, relatively loose internal structure, uneven stress during tensile testing, and easy wear of the clamping jaws that hold the specimens, the fixtures for steel wires and steel strands have not been well solved. In the past, it was done by sandwiching aluminum foil, and four pieces of aluminum foil were consumed in one experiment, which was a huge waste. We have now adopted a tensile testing machine fixture for spraying diamond sand, which has solved the problem of slippage. However, the fracture position has not been ideal, and only about half of the 10 samples can be successfully tested.

5. For materials with large deformation, clamping is difficult due to excessive deformation, and the design of fixtures is also a challenge.

6. For experiments that need to be conducted in high temperature environments, the requirements for vortex flowmeter fixtures are also very high. They need to be resistant to high temperatures, not deform, and have a small volume. Therefore, it is also difficult for general testing machine manufacturers to handle.

7. For large-scale and high-frequency experiments, fully automatic clamping is commonly used abroad, which is still a new challenge compared to domestic testing machine manufacturers

8. For the testing of finished and semi-finished products, various fixtures are required. How to personalize and meet customer requirements is a challenge for all testing machine manufacturers.