A FEM study of heat assisted filament winding process

An efficient quality control of produced materials is one of the topical aspects in industry, strongly contributing to the repeatability in the final part properties. Unfortunately, the importance of this task is often underestimated, and stringent procedures during the material production stage are seldom adopted, especially when small and medium enterprises are concerned. Filament winding is a high speed lay down of continuos prescribed patterns used for the composite materials pipes production where a continuous resin-impregnated rowing or tows are wound over a rotating male mandrel. In this process, vantage as optimised mechanical property, large structure production, low cost are contemporarily achieving. However the final results can not be independent from control process considerations, so we have focused attention on two main problems: thermosetting polymers cure conditions and thermoplastic polymers softening conditions varying the thermal source and the winding speed. These aspects influence directly the mechanical properties, the fatigue resistance, the produced residual stress and the related deformation, and, from another point of view the process control. In this work, the heating of the composite with an external source, during the fabrication process, is faced to the aim to model the heating flux and thermal gradient in the materials and then the temperature achieved. In a first step, a FEM model was developed to set the film coefficient. In order to calibrate the FEM model, experimental tests were performed on a composite substrate to measure the temperature profile in several positions during the heating process. In a second step, a new FEM model was developed in order to simulate the relative movement between the composite wound on the mandrel and the heating flux and calculate the temperature profile in the composite substrate. The results obtained were related to experimental data obtained in analogous conditions during the filament deposition. In a third step, the last FEM model was modified in order to consider several different types of thermal source and the influence of the thermal source type on filament winding process. The obtained results was related to the experimental data from literature. The analysis results show that finite element method is able to describe with accuracy the heating process during the filament winding process. So, we can define a first procedure to set the most favourable winding speed and thermal source varying the resin and fibre types.