Design And Experiments Of Bidirectional Torsion Testing Machine At Elevated Temperature

The rapid development of science and technology, and gradual improvement of thehuman life condition, especially the increasing pressure of population, resource andenvironment, all of these factors have put forward higher requirements on materialscience and technology. And new materials play roles of support and guide on otherhigh-techs, the level of research and industrial scale have become an importantindicator of economy, technology and national defense strength. In order to ensure thelong-term reliability of all kinds of materials and products, material performancetesting is particularly important.Through an in-depth study on the existing testing techniques and methods ofmaterial micro-mechanical properties, a review was made on domestic and foreignprogress in the relevant areas, and emphasized on mainstream commercial mechanicaltesting machines which are technically mature and small in-situ mechanical testingequipments, while a more detailed analysis was done at the coupled field oftemperature and mechanical load testing technology. As there is no machine can beseparated from the external environment and work independently, constantlysubjected to ambient temperature, external magnetic field, electric field and manyother physical fields. Therefore, in addition to withstanding stress effect, theoperations of temperature and other physical field tests of mechanical properties hasspecially practical significance. Combined with comprehensive analysis of progress athome and abroad, problem of poor function extension existing in conventional torsiontesting machine, in this dissertation, we designed and developed a bidirectionaltorsion testing machine at an elevated temperature mode, you could conduct thetorsion mechanical testing experiments within the temperatures ranging from roomtemperature to400°C. which can provide more abundant experimental evidences foranalyzing torsion mechanical properties of materials under elevated temperature condition.First, this thesis introduced the basic method and principle of typical plastic andbrittle materials while bearing the torsion load, and then a analysis was made on thefunction and unit structure principle, simultaneously theoretical checking calculationswere conducted on key components, to validate the rationality of structure design, onthis basis, by using the software of FEM(Finite Element Method), operated asimulation of practical service conditions under varies of constrains, also somemechanical simulation analysis of the whole machine and key components werecompleted, and analyzed the results of the FEM simulation. We could get the modalcharacters from the modal simulation analysis of the whole machine and torque shaft,which could avoid component failures occuring due to resonance in the structuredesign. Furthermore, the FFT analyzer was used to measure actual frequency responsefunctions of the machine and torque shaft by the modal experiments on the spot. Inthe meantime it verified the effectiveness of simulation results, and made it clear thatwhat caused the errors between the simulation values and the measuring values.The dissertation conducted kinds of mechanical testing experiments contraposingaluminum alloy6061and grey iron HT150at several temperatures from25°C to400°C, by means of the experiments, we could get the torsion mechanical responsecharacteristics of the different materials. And at last two kinds of specimen fracturewere compared from the perspective of macro and micro by using SEM, and revealedthe deformation damage mechanism under the condition of variable temperaturesunder torsion load.