Composite Vehicle Side Door Structure for Weight Reduction
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Solution Overview
Problem
Automotive manufacturers face challenges in reducing the weight of vehicle side doors while maintaining structural integrity and safety to meet crash impact standards, as traditional metal components are heavy and costly, and replacing them with plastic materials compromises stiffness and durability.
Innovation Solution
A two-shell composite side door structure is developed using a plastic inner and outer shell with substantially unidirectional fiber strips, oriented at +45° to -45°, which provides structural integrity without metal support beams, allowing for weight reduction and cost savings while meeting EuroNCAP side impact and pole impact test standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal crash beams are used in side doors, then structural integrity and crash safety are improved, but weight and manufacturing cost increase
Solution Approach 1:
The patent applies composite materials by combining plastic matrix with unidirectional fiber strips (≥50 wt.% fibers oriented at +45° to -45°) to create a door structure that achieves steel-level strength without the weight penalty. The composite inner and outer shells with strategically oriented fibers provide the necessary structural integrity for crash safety while significantly reducing door weight.
2Reliability
If metal crash beams are used in side doors, then crash safety is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive metal crash beams with cost-effective plastic composite materials that meet EuroNCAP crash safety standards. The unidirectional fiber-reinforced plastic structure provides the necessary reliability for side impact and pole impact tests while reducing manufacturing complexity and cost.
Solution Approach 2:
The patent changes material parameters by using fiber orientation angles of +45° to -45° in the composite structure, which optimizes the mechanical properties to meet crash safety requirements. This parameter optimization allows the plastic composite to achieve the same safety performance as metal at lower cost.
3Weight of moving object
If plastic materials are used to reduce weight, then weight is reduced, but stiffness and durability deteriorate
Solution Approach 1:
The patent uses unidirectional fiber-reinforced plastic composites with ≥50 wt.% fibers oriented at +45° to -45° to achieve both weight reduction and maintained stiffness. The fiber reinforcement provides the necessary structural rigidity and durability while the plastic matrix keeps the overall weight lower than traditional metal doors.
Data Source
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AI summary
In an embodiment, a side door for a vehicle can comprise: a structure comprising a plastic inner shell comprising a fiber strip, and a plastic outer shell comprising an outer shell support beam positioned across a width of the outer shell. The outer shell support beam can comprise a fiber strip with ≥ 50 wt.% fibers oriented at an angle of less than or equal to ±45° to a main axis. In an embodiment, a method for making the side door for a vehicle can comprise: flow molding a fiber-reinforced polymer over a fiber strip to form a plastic inner shell; flow molding a fiber-reinforced polymer over a fiber strip deposited to form a plastic outer shell, wherein the outer shell comprises an outer shell support beam positioned across a width of the outer shell; and joining the inner shell and the outer shell together to form a composite structure.