Browsing by Keyword "Intermediate strain rate"
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Item Design and Validation of New Torsion Test Bench for Intermediate Strain Rate Testing(2023-01) Bhujangrao, T.; Froustey, C.; Darnis, P.; Veiga, F.; Guérard, S.; Mata, F. G.; Tecnalia Research & InnovationBackground: 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.Item Review of intermediate strain rate testing devices(2020-07) Bhujangrao, Trunal; Froustey, Catherine; Iriondo, Edurne; Veiga, Fernando; Darnis, Philippe; Mata, Franck Girot; Tecnalia Research & InnovationMaterials undergo various loading conditions during different manufacturing processes, including varying strain rates and temperatures. Research has shown that the deformation of metals and alloys during manufacturing processes such as metal forming, machining, and friction stir welding (FSW), can reach a strain rate ranging from 10−1 to 106 s−1 . Hence, studying the flow behavior of materials at different strain rates is important to understanding the material response during manufacturing processes. Experimental data for a low strain rate of <101 s−1 and a high strain rate of >103 s−1 are readily available by using traditional testing devices such as a servo-hydraulic testing machine and the split Hopkinson pressure bar method, respectively. However, for the intermediate strain rate (101 to 103 s−1 ), very few testing devices are available. Testing the intermediate strain rate requires a demanding test regime, in which researchers have expanded the use of special instruments. This review paper describes the development and evolution of the existing intermediate strain rate testing devices. They are divided based on the loading mechanism; it includes the high-speed servo-hydraulic testing machines, hybrid testing apparatus, the drop tower, and the flywheel machine. A general description of the testing device is systematically reviewed; which includes the working principles, some critical theories, technological innovation in load measurement techniques, components of the device, basic technical assumption, and measuring techniques. In addition, some research direction on future implementation and development of an intermediate strain rate apparatus is also discussed in detail.