Composite Vehicle Door Reinforcement for Lightweight Impact Resistance
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Solution Overview
Problem
Current vehicle door assemblies are heavy, complex, and costly due to multiple subcomponents, which increases manufacturing time and decreases reliability, while also being inefficient in weight reduction and safety performance.
Innovation Solution
A simplified vehicle door assembly design using a composite reinforcement component formed by stamping or resin transfer molding, combining continuous or chopped fibers like glass, carbon, and cellulosic materials, which acts as a unified side impact cross beam, upper door reinforcement, and pillar reinforcement, reducing the number of components and weight while maintaining safety and surface quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multiple subcomponents are used to construct vehicle doors, then safety performance and structural integrity are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines multiple door subcomponents (upper frame, inner frame, reinforcement beams, and body panel) into a single integrated composite structure formed by resin transfer molding. This merging eliminates the need for separate side impact bars and reinforcement components while maintaining safety performance through the inherent strength of the carbon fiber reinforced polymer matrix.
Solution Approach 2:
The composite door assembly performs multiple functions simultaneously: it provides structural support, side impact protection, and aesthetic surface finish through a single integrated component. The carbon fiber reinforced polymer structure serves both as the load-bearing frame and as the outer body panel, eliminating the need for separate protective bars and reinforcement elements.
2Stability of the object's composition
If multiple subcomponents are used in door assembly, then structural integrity is improved, but manufacturing time and production cost increase
Solution Approach 1:
The patent integrates multiple door components into a single molded part that is manufactured in one continuous resin transfer molding cycle. This eliminates the need for separate manufacturing and assembly operations for side impact bars, reinforcement components, and body panels, significantly reducing manufacturing time while maintaining structural integrity through the integrated composite design.
3Weight of moving object
If carbon fiber is used to replace glass fiber, then weight is reduced and strength is improved, but surface quality and fiber flow control deteriorate
Solution Approach 1:
The patent applies different fiber types and orientations to different regions of the door assembly based on local structural requirements. Carbon fiber is used in areas requiring high strength-to-weight ratio, while the resin formulation and fiber distribution are locally optimized to ensure proper fiber flow and surface quality in visible areas. This localized approach allows weight reduction without compromising surface finish.
Solution Approach 2:
The patent modifies resin formulation parameters and curing conditions to optimize carbon fiber flow and distribution during resin transfer molding. By adjusting resin viscosity, injection pressure, and temperature profiles, the process achieves complete fiber impregnation and eliminates dry spots or fiber clumping, resulting in high surface quality despite using carbon fiber instead of glass fiber.
4Weight of moving object
If aluminum is used to reduce weight, then weight savings are achieved, but material cost and forming cost increase
Solution Approach 1:
The patent uses carbon fiber reinforced polymer composites as an alternative to aluminum alloy door assemblies. The composite material provides comparable or superior strength-to-weight ratio while being more cost-effective to manufacture through resin transfer molding. The composite structure can be formed into complex geometries in a single molding operation, eliminating the need for expensive aluminum forming and joining operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution results in a lightweight, cost-effective, and reliable door assembly that is 10-15% lighter than aluminum, with improved safety performance and manufacturability, while maintaining high surface quality and resistance to both side and frontal impacts.
Implementation Method 1
a cured inner layer of molding composition is reinforced with carbon fibers and joined to a cured outer skin of a second sheet molding composition
Implementation Method 2
The composite reinforcement component is formed by stamping or resin transfer molding (RTM)
Implementation Method 3
The use of fiber inclusions to strengthen a matrix is well known to the art. Well established mechanisms for the strengthening of a matrix include slowing and elongating the path of crack propagation through the matrix, as well as energy distribution associated with pulling a fiber free from the surrounding matrix material
Implementation Method 4
The use of carbon fibers in composites, sheet molding compositions, and resin transfer molding (RTM) results in formed components with a lower weight as compared to glass fiber reinforced materials. The weight savings achieved with carbon fiber reinforcement stems from the fact that carbon has a lower density than glass
Data Source
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AI summary
A lightweight and simplified vehicle door assembly is provided with four main components, an upper frame positioned about the window, an inner frame structure, an outer body panel, and a composite reinforcement component. The composite reinforcement component provides an all-in-one solution for a side impact cross beam, as well as an upper door reinforcement, a front door pillar reinforcement, and a rear door pillar reinforcement. The composite reinforcement component acts to reinforce the overall door structure, offers resistance to a side impact that limits the intrusion into the passenger compartment, and offers resistance to a frontal impact by maintaining the spacing between the vehicle A and B pillars (for a front door) and pillar C and D for a back door. A coupe vehicle door in which there is no window frame may be reinforced with the composite reinforcement component. The composite reinforcement component may have continuous or chopped fibers.