The Development And Testing Research Of Double Air Room Indirect Bar-Bar Impact Tensile Testing Apparatus

The technique of material dynamic experiment is more complicated than the quasi-static mechanical experiment, in order to simulate all kinds of speed rate of the impact loading process, the design of the testing equipment becomes one of key questions. The main content of this paper is design a set of double air rooms indirect bar-bar impact tensile testing apparatus which base on the one dimensional elastic stress wave principle, and the test of impact tensile experiment and the specimen numerical simulation are also studied.The idea of indirect bar-bar impact tensile testing apparatus is adopted by the design of the impact tensile testing apparatus in this paper , it is base on the one dimensional stress wave principle , and mainly base on the SHPB testing apparatus principal, as well as studied the impact tensile testing apparatus which has been designed. The symmetrically arranged double air rooms are adopted in the testing apparatus power system , and the high pressure air movement way is changed by the gas switch apparatus, and then the high pressure air pushes the circle ring bullet move . The high speed bullet impacts the stop block and quickly snap the metal short bar which is in the front of the apparatus, and the metal short bar LY12cz is approximately idealized elasticoplastic rate-irrelevant material, then produces a tension pulse , the tension pulse transmits in the incident bar , and quickly snapped the specimen, so the material impact tensile testing is realized .This paper introduces every component and its function of the testing apparatus in detail, and also the rate-irrelevant material tensile impact experiment is adopt to validate the reliability of the testing apparatus.This paper makes use of the self-development impact tensile testing apparatus to analyze the wave shape of the impact tensile testing. And the close relation between the stress wave profile and the metal short bar and the bullet speed is point out, meanwhile the strain gauge glue position on the incident bar is analyzed and tested.The ANSYS/LS-DYNA procedure is employed in chapter 5 to obtain the numerical simulation computation results of the dumbbell shape specimen which is used in the tensile impact testing. The stress pulse is directly acted on the testing specimen model in this paper to study the dynamic response of the specimen testing segment. The computation results show that, no matter the impact pulse magnitude, the specimen axial stress is far bigger than other direction stress, moreover the stress is even , and conform to the one dimensional stress situation. And also show that the dumbbell shape specimen which is adopted in the impact tensile experiment is reasonable.