A method for overcoming the relative slippage between the slab specimen and the bar in the hopkinson tension bar test

Abstract

The invention discloses a method for overcoming the relative slippage between the slab test piece and the bar in the Hopkinson pull bar test. A radial through-slot is processed on the top, a radial through-hole connected with the radial through-slot is processed at the bottom of the radial through-slot, and a screw mounting hole perpendicular to the radial through-slot is processed. Connection holes corresponding to the screw mounting holes are respectively machined at both ends of the slab test piece, and through the cooperation of the connecting screw with the radial through groove and the slab test piece, the seamless connection between the slab test piece and the connection screw is finally realized. Gap contact, combined with the large friction between the first and second pressing parts and the slab test piece, can effectively avoid the relative slippage between the slab test piece and the incident rod and transmission rod, ensuring The effectiveness of the test results can be greatly improved at the same time.

Description

technical field [0001] The invention relates to a method for overcoming the relative slippage between a slab test piece and a rod in a Hopkinson pull bar test, and is used for improving the validity of the Hopkinson pull bar test result and improving test efficiency. Background technique [0002] At present, scholars at home and abroad generally use the separate Hopkinson tension bar test device to study the dynamic tensile mechanical properties of materials under different strain rates. The tension rod of the Hopkinson tension rod test device includes a cylindrical incident rod and a transmission rod. During the test, the two ends of the tensile specimen are fixedly connected to the incident rod and the transmission rod respectively. Hopkinson tensile test pieces are usually cylindrical or plank. For the cylindrical Hopkinson tensile test piece, the Hopkinson tie bar and the test piece are connected by threads. Generally, an internal thread is reserved at the end of the Ho...

AI Technical Summary

Problems solved by technology

There are certain defects in the connection between the strip-shaped specimen and the Hopkinson tie rod by adding a fixture, which is shown as: for the connection between the fixture and the Hopkinson tie rod, there is still a certain gap between the external thread of the fixture and the internal thread of the tie rod after the two are connected. In the Hopkinson tensile test, the gap will cause relative slippage between the Hopkinson tie bar and the fixture; in addition, for the grooves on the fixture and the bolts to connect the strip specimens, the bolts and the bolts of the specimens No matter whether the bolts are tightened or not, there are gaps between the holes and between the specimen and the grooved surface. In the Hopkinson tensile test, it will cause slippage between the specimen and the fixture, and the bearing surface of the bolt hole of the specimen will Local uneven deformation occurs, making the circular bolt hole of the specimen become an elliptical hole

The above relative slippage and local uneven deformation of the bolt holes of the test piece will cause distortion of the measured data during the test, resulting in inaccurate test results

Although the relative slippage between the two and the local uneven deformation of the bolt holes of the specimen can be solved to a certain extent after the two are bonded together by applying an adhesive between the specimen and the grooved surface. However, the glue application process of the adhesive is cumbersome and time-consuming, and the curing of the adhesive after the glue application also takes a certain amount of time, and the adhesive cured in the groove needs to be removed before the test again, which also takes a long time

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