Flat Lightweight Member with Braided Skin and Thermally Expandable Core
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Solution Overview
Problem
Conventional methods for producing fiber-reinforced plastics face challenges in achieving lightweight members with excellent mechanical properties, adhesiveness between core and skin layers, and good appearance quality, particularly in complex shapes, due to issues like increased weight, reduced joint strength, peeling, and difficulty in maintaining precise moldings.
Innovation Solution
A method involving a braiding material with a separation layer in a bag shape, using fiber strands with varying densities and a rib portion, combined with a thermally expandable material, is employed to create a lightweight member with improved adhesiveness and surface quality by controlling fiber strand density and integrating the layers through controlled expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If prepregs are laminated and bonded at the end portion to ensure structural integrity, then mechanical strength is improved, but weight increases due to additional material in the core layer region
Solution Approach 1:
The patent applies local quality by varying the fiber strand weight per unit length along the longitudinal direction of the braiding material. The end regions use fiber strands with different weight per unit length compared to the central region, allowing optimized mechanical properties at the ends while maintaining lightweight characteristics in the central core layer region. This resolves the contradiction by providing enhanced strength where needed without uniformly increasing weight throughout the entire structure.
2Weight of moving object
If the end portions of prepregs are simply butted against each other to reduce weight, then weight is reduced, but joint strength is reduced and foaming resin leaks impairing appearance quality
Solution Approach 1:
The patent implements local quality through spatial variation of fiber strand properties. By using fiber strands with different weight per unit length in end regions versus the central region, the invention provides enhanced joint strength at the butted ends while maintaining lightweight properties in the central region. This prevents both the over-weighting of the entire structure and the weakness of simple butting joints.
3Ease of manufacture
If fiber strands with uniform density are used throughout the braiding material, then manufacturing simplicity is maintained, but mechanical properties at end portions are insufficient
Solution Approach 1:
The patent applies local quality by specifying that the braiding material includes fiber strands with varying weight per unit length along the longitudinal direction. The end regions use fiber strands with different weight per unit length compared to the central region, enabling optimized mechanical properties at the ends while maintaining a relatively simple braiding manufacturing process. This resolves the contradiction between manufacturing simplicity and end portion mechanical properties.
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 method produces a lightweight member with enhanced mechanical properties, adhesiveness, and appearance quality, while maintaining structural integrity and reducing production time and labor, suitable for complex shapes.
Implementation Method 1
a core layer formed of a thermally expandable material and a matrix resin
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(d)
Figure 3(a)~3(b)
AI summary
In order to provide a flat lightweight member including fiber reinforced plastics and having excellent mechanical properties of an end portion and excellent adhesiveness between a core layer and a skin layer as well as good appearance quality and excellent producibility, the flat lightweight member includes a skin layer including a braiding material and a matrix resin, a separation layer having a bag shape and being present inside the braiding material, and a mixture of a matrix resin and a thermally expandable material, the mixture being present inside the separation layer.