## 1 Introduction  
Thermoplastic matrix composites are substituting traditional long glass fiber composites made of thermosetting matrix for the production of small components in aerospace applications. The main advantages associated with thermoplastic matrix composites are the high shelf life of the prepregs, the higher reliability of the production processes and the simplification of the molding operations. However, typical thermosetting matrix composites processes have to be re-designed for the application to this new class of materials. An important example deals with filament winding process. Regarding thermosetting matrix composites a continuous prepreg is wound on a machine mandrel and subsequently cured in an oven. The typical material adhesivity (known as \"tack\") plays an important role in the material consolidation before curing in the oven. Thermoplastic prepregs have no tack properties and have to be joined during the winding operation. The authors have studied a laser-assisted process to allow the thermoplastic prepreg to adhere to the underlying ply simultaneously with its deposition. Use of a laser source to consolidate thermoplastic prepregs is not a novel technology. In 1992, [PERSON] _et al._ already proposed the thermal characterization of the laser-assisted consolidation process [1]. They discussed that this kind of technology was able to produce thermoplastic composite parts of excellent quality and structural integrity, combining the advantages of the traditional thermosetting filament winding technology with the faster processing times of thermoplastic prepregs. The experimental apparatus for the laser-assisted consolidation process consisted of a mandrel mounted on a rotational table, a fixed compaction roller, and an 80 W CO\({}_{2}\) laser. Two ZnSe lenses were used to focus an 8 mm diameter beam into a 6 \(\times\) 0.5 mm\({}^{2}\) planar beam, and no winding tension was applied. Experimental tests were carried out on continuous carbon fiber reinforced PEEK prepregs. In 1997, [PERSON] _et al._ used a similar consolidation apparatus to process the same material, deepening the effect of the process parameters on the properties of the consolidated composite [2]. They chose to apply a high compaction force in combination with the pre-heating of the compaction-roller: as a result, consolidated composites showed a typical shear strength about 50% of the autoclave processed composites. In 1999, the same consolidation apparatus was used again to process wider prepreg tapes made of carbon reinforced PPS [3]. After that, no further studies about laser-assisted filament winding of thermoplastic prepregs were carried out, even though new interesting materials and laser sources entered the market. In 2003, [PERSON] and [PERSON] proposed a thermal model for on-line laser curing of thermoset composites in filament winding, but no experimental tests were performed [4]. No mention is given to laser-processing of long glass fiber reinforced polypropylene (PP) prepregs, although this new composite material has gained high interest in the scientific world. In 2000, [PERSON] and [PERSON] studied the sheet extrusion and thermoforming of discrete long glass fiber reinforced PP [5]. During extrusion, the long glass fibers were organized into coherent fiber mats which persisted into the solid state, and were able to withstand the deformation process by thermoforming. In 2004, [PERSON] _et al._ presented the stamp thermoforming process which involved supporting the thermoplastic sheet with a bed of heated viscous fluid that applied a hydrostatic pressure across the part throughout the forming process [6]. Experiments were performed on a random oriented continuous glass-mat fiber reinforced PP by means of a hemispherical punch. Dealing with filament winding, numerical simulations are mainly discussed: a first contribution was given by [PERSON] _et al._ in their study about the simulation of thermal residual stresses in thermoplastic filament winding [7].