Material testing machine for superposition of tension/compression, torsion and internal pressure

点击翻译按钮获取中文摘要

The damage and failure behavior of metallic structural materials is significantly dependent on the local stress state. Damage models, that are used to both evaluate material and component integrity as well as to simulate forming processes with the aim of damage control, describe this stress state dependency by using corresponding material parameters. The calibration of these parameters as well as the validation of the models require a test technique with the help of which the stress states in specimens can be set in a defined manner. However, such a test technique is currently not available at the applicants’ facilities. Instead, the stress state is generated by adjustment of the specimen geometry within the framework of uniaxial tests, whereby neither arbitrary stress states can be set, nor can non-proportional strain paths be reliably avoided. This is to be remedied by the testing machine applied for, which superimposes normal and shear stresses onto hydrostatic stresses generated by internal pressure thus enabling the systematic setting of specific stress states. The applied for testing machine is a unique machine that cannot be found in the manufacturers’ catalogs because, in addition to tensile/compression as well as torsion testing, it also provides for the application of internal pressure to hollow specimens. Therefore, the machine must be individually adapted to the wishes of the applicants as formulated in the present proposal. To this extent, the testing machine will be unique at the Aachen location.As all three applicants are affiliated in the Center for Metallic Design, the center was selected as the location for the machine. This choice of location ensures optimal use of the machine by all applicants. The testing machine is also to be integrated into the virtual StrucMatLab founded by the Division of Materials Science and Engineering. This will leverage synergy effects in terms of follow-up as well as maintenance costs and furthermore, increase the accessibility of the machine for scientists, especially from the Faculty of Georesources and Materials Engineering.Many research projects that are already underway or have just been applied for will benefit from the procurement of the testing machine, covering both basic science and more application-oriented projects from the fields of materials science and materials engineering, production engineering (forming technology) and civil engineering (steel construction).