Thermoplastic composites: the new wing for aerospace

Glass fiber reinforced thermoplastic Composite (GFRTP)

Glass fiber reinforced thermoplastic composite is a new type of composite material which is composed of glass fiber as reinforcement and high performance thermoplastic resin such as polyether imide, polyphenylene sulfide and polyether ether ketone as matrix. GFRTP is widely used in automotive, electromechanical and other fields due to its advantages of low cost and electrochemical corrosion resistance.

Fokker of the Netherlands is the first company to make GFRTP into an aircraft cabin floor through a hot pressing process, and successfully applied to the Fokker100 regional jet. Airbus has unveiled its new A400M military transport aircraft with deicing plates designed to protect the sides of the fuselage from ice breaking off propellers in bad weather. The Ten Cate Cetex® semi-prepreg used in the A380 “J-head” is a GF/PPS thermoplastic composite with excellent impact and chemical resistance.

PPS is a semi-crystalline thermoplastic with excellent processing properties, good flame retardant properties, high temperature resistance and corrosion resistance, excellent mechanical properties and good dimensional stability.

Tencate, an American company, has produced carbon fiber reinforced polyphenylene sulfide based composites through fabric hot pressing. The material is also used in the main wing edges of Airbus A340 and A380 aircraft, the aileron structure of A340 aircraft, the Fokker50 aircraft landing gear door stress rib and girder, the G650 business jet tail, rudder and elevator components. Xu Yingkai [3] achieved the strengthening and toughening of PPS matrix by regulating the crystalline structure of PPS, and finally established the molding method of PPS/CF composites with high strength.

Molding technique

1.Hot pressing
The main method of thermoplastic composite molding in hot press molding, according to different equipment can be divided into die molding, double film molding, autoclave molding and vacuum bag molding. The basic process is to cut the prepreg and put it into the mold to heat up. After reaching the molding temperature, the prepreg is pressurized with different equipment to obtain the final parts that meet the requirements. Hot pressing can make rapid forming of some parts with variable thickness and complex shape, such as beam and girder.

2.Winding forming
Winding molding has the advantages of low cost and high efficiency. The thermoplastic prepreg tape is first dry wound and formed, and then cured in a curing furnace or autoclave. In situ curing process can also be used to form, the continuous prepreg belt preheated by heating furnace is wound on the corresponding core mold, and the heat source is used to melt the resin while winding, and the prepreg is bonded layer by layer to form a thermoplastic composite finally. It is more suitable for the manufacture of circular section parts.

3.Fiber hybrid method
The key of fiber hybrid method is to prepare the resin fiber with the same diameter as the reinforced fiber, and then mix the two fibers into a composite yarn, and then braid into a prepreg, or directly braid with two fibers. Fiber hybrid method can obtain prepreg material with good softness and draping properties, and it is easy to control resin content, fiber can be fully infiltrated, and can be directly wound to form parts .

4.Automatic fiber laying in situ curing process
The automatic fiber placement in situ curing process refers to the introduction of the corresponding curing source in the layer-by-layer preforming stage of the composite material, so that the top several layers are solidified, and the parts are solidified at the same time.