The purpose of lightweight body is to improve the market competitiveness of vehicle products without increasing the manufacturing cost of the body while ensuring the collision, rigidity, strength and NVH performance of the body structure.

Lightweight Materials

The continuous expansion of high-strength and lightweight materials used in the body of lightweight materials mainly include high-strength steel and ultra-high-strength steel, aluminum alloy, magnesium alloy engineering plastics, and compliant materials.

high strength steel

High-strength steel is mainly used in the main parts of the front collision beam, A, B, C column reinforcement plate, threshold beam, door collision beam, roof beam, etc., and gradually expanded due to public expenses.

Aluminum alloy

Aluminum alloy gradually extends from the hood to the wings, trunk lid and doors, some luxury cars have achieved all aluminum body.

magnesium alloy

Magnesium alloy has developed from steering wheel frame and seat frame to support and drive train housing parts.

fiber reinforced composites

Fiber-reinforced composite materials began to be used in previous modules, rear doors, intake manifolds and other components. Carbon fiber composite materials have expanded from sports car and luxury cars to intermediate cars and electric vehicles. For example, a car body structure with four doors and two lids.

structural optimization design

In terms of structural optimization design, it is more important to make a more reasonable design plan for the body structure in the early stage of vehicle development. At present, the lightweight design of multi-lightweight material body structure is building a parametric design platform (as shown in the figure), and is developing towards topology optimization, size optimization, shape optimization, multi-objective optimization and structure-material-performance integrated optimization design.

Application of 1. Lightweight Materials

1. High-strength steel

High-strength steel is mainly used in the interior and exterior panels and vehicle structural components. High-strength steel can effectively improve the passive safety of the vehicle body. Advanced rigidity is applied to automobile super-hard body and advanced concept car, and has good prospects in weight loss, energy saving, safety improvement, and emission reduction. Although facing problems such as springback in forming, high-strength steel is a cost-effective and attractive material compared to other alternative materials.

2. Aluminum alloy

The application of aluminum alloy began in the 1990 s and represented the all-aluminum space frame body introduced by Audi.

Deformed aluminum alloy has developed rapidly in the application of body parts level structure, including more and more widely used aluminum trunk lid, engine hood, door, bumper beam and so on. With the development and application of new materials such as solidified aluminum alloys, powder metallurgy aluminum alloys, superplastic aluminum alloys, aluminum matrix composites, and foamed aluminum, the scope of application of aluminum alloys in automobiles will be further expanded in the future.

3. Magnesium alloy.

At present, magnesium alloys are mainly concentrated on the steering wheel frame on the body. The instrument panel frame, seat frame and other parts have not been mass-produced on the body-in-white structural parts. It has only been tried on one of Chrysler's models so far. Magnesium alloys have not been widely used due to their internal edible properties and formability limitations.

4. Composite Materials

Automotive industry composite material technology is first applied to bumpers, and then the production of variable cross-section spring steel plates instead of steel plates, followed by the production of 4 doors and 2 covers.