Design and Validation of New Torsion Test Bench for Intermediate Strain Rate Testing

Background Many traditional experimental testing devices like hydraulic testing machines, Split Hopkinson bar technique, etc. are available to recreate the same material behaviour that occue during manufacturing processes at different strain rates. But the fact is that a state of large equivalent strain with dominant shear strain at intermediate strain rate is not easily achievable using these devices. Objective The goal of this work is to design and develop a new dynamic torsion device based on the principle of the flywheel at intermediate strain rates in order to study the shear behaviour of the material that typically occurred during the manufacturing process. Methods A general description of the testing device is given systematically in this paper. Hopkinson bar sensor as a load measuring technique is used to measure the applied torque on the specimen and the shear deformation of the specimen is measured by the grid pattern technique. Results After the design and manufacturing of torsion device, some experimental tests on AA7075-T6 alloy are presented for validation of the device. The preliminary experimental results are attractive. It shows that the material can be tested at an intermediate strain rate by varying the speed of the flywheel. Conclusions The use of this newly designed torsion device with an appropriate methodology of load and deformation measurement, finally allows us to obtain the mechanical pure shear behavior of materials under intermediate strain rate loading.