Glass mat reinforced thermoplastic composite material (Glass Mat Reinforced Thermorplastic, referred to as GMT) refers to a novel, energy-saving and lightweight composite material that uses thermoplastic resin as the matrix and glass fiber mat as the reinforced skeleton. It is currently an extremely active composite material in the world. The development of materials is regarded as one of the new materials of the century.
GMT can generally produce sheet semi-finished products, and then directly process them into products of the desired shape. GMT has complex design features, excellent impact resistance, and is easy to assemble and rework. It is praised for its strength and lightness, making it an ideal structural component to replace steel and reduce mass.
1. The advantages of GMT materials
High specific strength: The strength of GMT is similar to hand-laid polyester FRP products. Its density is 1.01-1.19g/cm, which is smaller than thermosetting FRP (1.8-2.0g/cm), so it has a higher specific strength.
Lightweight and energy-saving: The weight of the car door made of GMT material can be reduced from 26Kg to 15Kg, and the thickness of the back can be reduced, so that the space of the car is increased. The energy consumption is only 60-80% of the steel products and 35-50 of the aluminum products. %.
Compared with thermosetting SMC (sheet molding compound), GMT material has the advantages of short molding cycle, good impact performance, recyclability and long storage period.
Impact performance: GMT's ability to absorb impact is 2.5-3 times higher than that of SMC. Under the impact of impact, SMC, steel and aluminum all have dents or cracks, while GMT is safe.
High rigidity: GMT contains GF fabric, which can maintain its shape even if there is an impact of 10mph.
2. Application of GMT materials in the automotive field
GMT sheet material has high specific strength, can produce lightweight parts, and has high design freedom, strong collision energy absorption, and good processing performance. Since the 1990s, it has been widely used in the automobile industry abroad. With the increasing requirements for fuel economy, recyclability and ease of processing, the GMT material market for the automotive industry will continue to grow steadily.
At present, GMT materials are widely used in the automotive industry, mainly including seat frames, bumpers, dashboards, hoods, battery brackets, pedals, front ends, floors, guards, rear doors, car roofs, luggage Brackets, sun visors, spare tire racks and other components.
1. Seat frame
The compression molding design of the second row of seat backs on the sports car is made of 45% unidirectional glass fiber reinforced glass fiber mat thermoplastic composite material (GMT) and molds, which are compression molded to successfully meet the challenging conditions of maintaining luggage load European safety regulations.
This component requires more than 100 FEA iterations to complete, eliminating five parts from the earlier steel structure design, and saving 3.1 kg per car in a thinner structure, and is easier to install.
2. Rear anti-collision beam
The anti-collision beam at the rear of a car is made of GMT material. Compared with steel products, the weight is lighter and the cushioning performance is better. It reduces the weight and fuel consumption while ensuring safety performance.
3. Front-end module
In the luxury coupe, fabric-reinforced thermoplastic composites are selected as the front-end module components.
Two-door sports car front module
4. Under the body guard
The undercover protection made by high-performance GMT is used in off-road special edition.
5. Tailgate skeleton
In addition to the usual advantages of functional integration and weight reduction, the GMT tailgate structure also realizes the formability of GMT products that are impossible to achieve with steel or aluminum.
GMT material tailgate skeleton
6. Dashboard frame
The new concept of GMT manufacturing instrument panel frame has been used in several car models. These composite materials can achieve a wide range of functional integration, especially by including the vehicle beam in the form of a thin steel tube in the molded part, and compared with the traditional method, the weight is greatly reduced without increasing the cost.
GMT manufacturing dashboard frame
7. Battery bracket
GMT made battery bracket