Experimental and Numerical Simulation of Titanium Flow Forming

Elisabeth Massoni, Dorian Depriester



An increased need of research studies in the aeronautic industries is notice lately. This is mainly due to the economic situation in Europe where we are trying to get the most benefit of knowledge from the automotive sector. The objective is to improve, through numerical simulation and optimization development, the production of safe parts without damage and with good final mechanical properties in a very short time. The current trend is focusing on reducing the aircraft weight. The aeronautic industry responds to this request by the use of composites reinforced by carbon fibers. The structural elements that maintain the carbon fiber components are increasingly made of titanium and form the supporting structure of a modern airliner. It appears that the titanium will be increasingly important in the construction of aircraft, whether civilian or military. The consumption of titanium mechanically increases with the emergence of ongoing programs such as the new aircraft "composite" (B787, A350). Titanium alloys are usually used in the aeronautic industry to form structural parts of planes mainly because of their superior strength to weigh ratio. The Ti-6Al-4V α −β alloy is nowadays the most used in the aeronautic industry, and forms with hot process (superplastic forming, hot deep-drawing). But in order to reduce the production cost, cold forming processes are proposed. In this paper, we will then explore one interesting application of titanium forming in aeronautic industry like cold flow forming of Ti-6Al-4V. Modelling the incremental processes like flow forming process is complicated due to the high concentration and complex geometry of contact zone. This lead to high gradients of stress and strain rate which are continuously moving all over the workpiece. This characteristic of the process requires in particular adapted mesh management. We will see the most important points on which we must focus: mesh optimization, computing time and validation through experimental tests.