Determining the quality of a tensile testing machine fixture can be challenging due to the unique construction. For a particular fixture, it's often difficult to ascertain its suitability for a specific specimen. Typically, the following three points are considered: ease of use and safety of the fixture, whether the grip is reliable without any slippage, and during the testing process, the specimen's break point is favorable with minimal data dispersion (i.e., the specimen does not frequently break at the clamping area, inside the clamping area, in the parallel section, or beyond the gauge length). However, for some types of materials, which have specific characteristics and application environments, there are few solutions available to date. For steel wire and steel strand, due to the high hardness of the specimens and the relatively loose internal structure, uneven force distribution occurs during the tensile test, and the clamping area is prone to wear. The fixtures have not been well addressed. Previously, aluminum foil was used, consuming four sheets per test, which was highly wasteful. Now, fixtures coated with金刚砂 have been adopted for the tensile testing machine, solving the slippage issue, but the ideal break point has not yet been achieved, with only about half of the 10 specimens successfully breaking.
Regarding materials with high deformation, it's challenging to hold them due to their excessive deformation, making the design of the fixture a难点. As for experiments conducted under high-temperature conditions, the fixture requirements are also stringent; they must withstand high temperatures without deforming, while also being compact. For manufacturers of standard experimental machines, this is a difficult task to accomplish.
In terms of large-scale, high-frequency experiments, fully automatic clamping is commonly used overseas, which is still a new challenge for domestic experimental machine manufacturers. For the detection of scrap and semi-scrap products, the variety of fixtures required is diverse. How to individually meet customer requests poses a challenge to all experimental machine manufacturers.
