| Because of the complexity of the impact shear tests, changes of the SHPB device were required when the double-shear specimens were loaded by the traditional SHPB. The special contact interface or switching devices were required between the pressure bars and the specimen which brought inconvenience to the tests. In addition, to obtain strain rates that exceed 104 s-1 in material tests under dynamic shearing, pressure-shear plate impact technique or direct impact method with an air-gun launched projectile has to be used nowadays. In this paper, a new double-shear specimen for impact shear experiments was proposed, based on the traditional SHPB and single pulse loading techniques. With the new design of double-shear specimen, the dynamic shear properties of metal materials could be measured precisely. Besides, the quasi static shear properties were obtained by the new double-shear specimen.Repeated loading could be avoided by the single pulse loading technique and the microstructure evolution of the recovered specimen could be analyzed. The shear stress-shear strain curves were acquired with this testing method at different shear rates. In this paper, shear stress-shear strain curves of 603 steel, TC4 and pure copper were acquired at strain rates between 0.001 and 75000 s-1, respectively. The deformation process could be observed by high speed camera directly. The fracture surfaces of specimen were anal yzed by the SEM, and the micro-morphology of the surfaces were observed.The dynamic loading process was modeled by ABAQUS/Explicit to verify the validity and accuracy of the test results. The simulation results showed that the stress and strain fields in the main shear zone were distributed uniformly along the direction of width and thickness. The test curves had good agreement with the simulation results by the comparison. The new double-shear specimen proposed in this paper could provide an effective wa y to test dynamic shear mechanical properties of materials. |
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