Tube expansion by gas detonation

摘要

The expansion of tubes by direct application of gas detonation waves is an alternative forming method for hollow section workpieces. In particular the process can be used for typical hydroforming parts, for example car body or exhaust elements in automotive industry. The gas charge of oxygen and hydrogen is both pressure medium and energy source and has the potential to cause high forming velocities. The introduced process belongs to the category of high speed forming methods and provides typical advantages such as higher achievable strains compared to quasi-static methods using high water pressure. Another advantage of this process is the avoidance of high press forces by application of an “inertia-locked tool” system due to the extremely short process time. To develop a controllable process, good knowledge of the interdependencies in the system “medium, workpiece and tool” is essential. This can be achieved using simulations in combination with experimental investigations. The results are topic of this paper, also including special investigations on the material behavior at high strain rates and temperature gradients.