FILAMENT WINDING
Description
| The filament winding method is a process in which continuous resin-impregnanted rovings are wound over a rotating male mandrel or liner. The mandrel can be cylindrical, round, or any shape that does not have reentrant curvature. The reinforcement may be wrapped either in adjacent bands or in repeating bands that are stepped the width of the band and which eventually cover the mandrel surface. The technique has the capacity to vary the winding tension, wind angle or resin content in each layer of reinforcement. Mandrel removal, triming, and other finishing operation complete the process. |
|
| Manufacturing of a high-pressure air container |
Contacts
www.gaiker.es; dios@gaiker.es, madariaga@gaiker.es
Characteristics
| Costs (tooling / unit) | Mandrel are in principle unexpensive. (E.g.: Cilindrical mandrel of 1000 mm length and 150 mm diameter with a good surface finished may cost 1000€). (e.g.: mandrel for tanks of Polyester of 2-6 m diameter and 6-12 m length costs about 12000
€.
Liners of PE, PP, PET, Polyester, aluminium or steel may be used to wind around them, being the internal layer of the component. Liners of PE may be manufatured by rotomoulding or blow-moulding. Liners of PP or PET may be manufactured by blow moulding. Example of unit costs:Air pressure container (1000 mm length 150 mm diameter, 10 mm thickness) Cost of material: 180€ (epoxy-carbon fiber) |
| Volume (units / day) | One tank of polyester may be manufactured in 2 hours (without curing time in an oven). Curing times may vary between 4 and 16 hours depending on the type of resin.
One machine may fabricate 2 or 3 tanks at each time. |
| Possible Materials |
Fibers: Resins: |
| Size / Shape | The possible shapes are based in revolution surfaces.
Size: Ilimitated. The design possibilities depends on the type of machine: Tubes may be manufactured with a 2 axis machine Tanks may be manufactured with a 3 axis machine. For fittings and curved shapes are neccesary 4 or 5 axis. |
| Mechanical Properties | Depends on the type of fiber, type of resin, % of fiber, and orientation of fiber. The angle of orientation may be different in each
layer.
Glass fiber. Type E: Strand nominal tensile modulus (GPa): 72.4 Strand nominal tensile strenght (MPa): 3447 Fiber density (g/cm3): 2.60 Graphite fiber. High tensile strenght: Strand nominal tensile modulus (GPa): 227 Strand nominal tensile strenght (MPa): 3102 Fiber density (g/cm3): 1.75 Polyester resin: Tensile modulus: 3309 MPa Density (g/cm3): 1,135 |
| Special Remarks | A 3 axis machine may cost around 150000 €.
Applications:Hydraulic, oil industry, aeronautic and space industry, defense, nuclear industry, oof-shore industry, mechanical and electromechanical industry, leisure industry. |
Application / Case Study
An application of the filament winding method is the design of a high-pressure air container, as in the fotograph above. The analysis begins with determination of all requirements, including envelope (lenght and diameter), performance (pressures, weight, and volume), environment (temperature, humidity, and external loads, and interfaces (other stages, nozzles).
With these parameters known, a preliminary design is performed using netting-analysis methods to address the defined loads. Material selection es dictated by performance and environmental constrains. Windability is a major concern, requiring proper selection of wind methods to match the selected geometry with available equipment.
Next, a detailed analysis is performed using the selected wind angles, the calculated fiber thickness and the resulting composite weight. Polar bosses and skirt thicknesses are selected and trade studies are performed to optimize the design.
Finally, the detailed stress analysis is performed using finite-element techniques. The thickness of the shear plies at the polar bosses and at the skirt/case interface is analyzed with computer techniques.
The design is verified when a full-scale unit is proof-tested and hydroburst, and eventually acoustical measurements.
Filament winding