Papers by Keyword: Drop Tower

Abstract: The rebound-effect that frequently occurs during electromagnetic sheet metal forming is one of the main causes of deviations in the shape and dimensional accuracy of flat surfaces. The selection of the die material and its corresponding energy absorption capabilities has a critical impact on this effect. This article analyses materials with different physical properties in terms of their energy absorption behavior under dynamic impact load. A variety of model tests are being conducted to examine a wide range of impact velocities and energies. The experimental setups comprise two variations of a drop tower test, which can be used to determine the percentage of impact energy absorbed at high and low momentum. To achieve higher impact velocities, a third experiment involving an electromagnetically accelerated impact body was conducted for the material that demonstrated the best result in the preceding tests.

Abstract: The behaviour of concrete slabs under dynamic load such as rock fall or vehicle impact isinvestigated in this work. The aim of this study is to enlarge the knowledge concerning thesubsequent reinforcing of concrete slabs and its inuence on their behaviour under impact load.Therefore, the results of the drop tower experiments with standard concrete, high performanceconcrete (HPC) and ultra-high performance concrete (UHPC) are compared and interpreted.The analysis of the test results focuses on the qualitative evaluation of the protective e ectand on the quantitative evaluation of measurement results. Regarding the protective e ect, theinuence of the additional steel stirrup reinforcement is rather small. In contrast, the subsequentfabric reinforcement prevents the perforation of the concrete slabs. The behaviour of steel fabricand carbon fabric is compared. Although particular di erences in fracture behaviour are seen,both types of fabric reinforcement obviate total punch-through and, hence, vastly enhance theprotective performance. Comparing the stamping cones and analysing the extent of damage, theprotective capacity of di erent concrete slabs is evaluated. Within the quantitative evaluationof the measurement results, the evolution of strains and strain rates is being considered. Onthe top side of the concrete slabs, the strain is measured as tensile strain in the rst spellafter load application, turning into compressive strain later on. The evolution of strains andstrain rates indicates wave propagation. Beside the strain results, special attention is paid tothe correlation of di erent measurement techniques. The results of strain gauges, accelerometer,load cells and photogrammetry are contextualised and therefore show the change from the localmaterial behaviour to the global structure response in temporal sequence.

Abstract: Although inception of the measurement of astronaut body mass measurement was as old as Skylab era, progress in the field has not been as expected. There are fundamental physical difficulties as well as program management issues. New mass measurement systems with the current sensor technologies should be prepared, and the new sensor system could be expanded for “Drop Tower” in space.

Abstract: Reduced gravity experimentation is important to many research groups working in various fields investigating both fundamental and applied aspects of diverse physical phenomena. Very few terrestrial or extra-terrestrial experimental facilities are currently available that allow researchers access to reduced gravity environments. The Queensland University of Technology’s has recently fabricated a purpose built, stand alone 2.0 second drop tower specifically to accommodate reduced gravity experimentation. The specifications and operational procedures of this new research facility are presented. Information concerning current and future areas of research is also presented and discussed. These research areas include: 1) cellular biology, 2) fluid dynamics and multiphase flow, 3) nanomaterial production including silica sol-gels and carbon nanotubes, and 4) heterogeneous combustion with a focus on bulk metallic materials burning in oxygen enriched atmospheres performed in collaboration with NASA and industry partners. Discussion on the use of the new research facility in the production of advanced materials for earth-based applications will be presented. Opportunities will also be discussed regarding both collaborative research and the provision of reduced gravity test services.