Filament winding process

Filament winding Process in which continuous strands of roving or... 

In order to understand the effect of each process variable, a fundamental understanding of the heat transfer and polymer curing kinetics is needed. A systematic experimental approach to optimize the process would be expensive and time consuming. This motivated the authors to use a mathematical model of the filament winding process to optimize processing conditions. 

This paper will discuss the formulation of the simulator for the filament winding process which describes the temperature and extent of cure in a cross-section of a composite part. The model consists of two parts the kinetic model to predict the curing kinetics of the polymeric system and the heat transfer model which incorporates the kinetic model. A Galerkin finite element code was written to solve the specially and time dependent system. The program was implemented on a microcomputer to minimize computer costs. 

Filament winding Process in which continuous strands of roving or roving tape are wound, at a specified pitch and tension, onto the outside surface of a mandrel. Roving is saturated with liquid resin... 

Figure 7.91 Schematic diagram of the filament winding process. Reprinted, by permission, from P. K. Mallick, Fiber-Reinforced Composites, p. 352. Copyright 1988 by Marcel Dekker, Inc.

Process models allow composite case manufacturers to determine the affects of process variable settings on final cylinder quality. Because the cost of a composite cylinder can be as great as 500,000, the ability to simulate filament winding can significantly reduce cost and improve quality. Several computer models of the filament-winding process for both thermoset and thermoplastic matrix materials have been developed. These models are based on engineering principles such as conservation of mass and energy. As such, numerous resin systems and fiber materials can be modeled. 

Figure 28.9 Scheme of the filament winding process. Source Adapted from http //www.polymerprocessing.com/operations/ filwind/index.html, with permission. 

Shell Chemical has produced EPON HPT epoxy resins, which are used in large parts made of graphite-7 reinforced prepreg material for primary aircraft structures. EPON 9000 series of epoxy resins produced by the same company have been used for fabricating, by wet filament winding process, fuselages and other large components that have been used in the prototype of Beech Aircraft s experimental small business aircraft, the Starship 1. 

Figure 4 Fabrication of epoxy FRP wood sample by filament winding process.

This is similar to the filament winding process, but the mandrel is made of a continuous steel band. The vessel is wound on the mandrel, at the end of which the steel band is fed up the centre of the vessel to the beginning, in order to recommence. Frequently, sand and chopped fibres are also dropped on to the mandrel to increase the thickness and thus stiffen the vessel. 

Fig. 54 Pipe production using the filament winding process (schematic)...

Higher strengths are achieved when the fibers are not randomly distributed but are directionally worked in. For example, the tensile strength of an epoxide resin increases from 60 to 200 MPa after working in glass fiber in the form of woven mats, and even increases to 1 200 MPa if the glass fiber is worked in by the filament winding process. 

In the filament winding process a mandrel is rotated upon which are wound reinforcing fibres which have been impregnated with resin. The fibre is controlled by an applicator which traverses the length of the mandrel as it rotates, thus building up the laminate thickness. A surface of revolution is produced, the type (cylinder, cone, etc.) depending on the mandrel shape. Variations include extra axes of movement to allow the winding of domed ends, spheres, conical shapes, etc. 

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