Vehicle-Body Structural Component with Fiber-Preserving Projections
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Solution Overview
Problem
Existing methods for fixing components within hollow structures made of fiber-reinforced resin, such as carbon fiber-reinforced resin (CFRP), face challenges in maintaining structural integrity and complicating the manufacturing process, particularly when using bolts, which can cut fibers and reduce strength.
Innovation Solution
A method involving molding a continuous fiber impregnated with thermoplastic resin into a cylindrical shape, disposing a component inside, and deforming the resin to form projections that support the component while maintaining fiber continuity, thereby forming a vehicle-body structural component with integrated projections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bolts are used to fix components within hollow structures made of fiber-reinforced resin, then component fixation is achieved, but fibers are cut and structural strength is reduced
Solution Approach 1:
The projection is formed as an integrated part of the hollow structure body, merging the fixation feature directly into the structural component. This eliminates the need for separate fasteners like bolts that would cut fibers, while maintaining structural integrity through the continuous fiber reinforcement in the projection region.
Solution Approach 2:
The projection is formed during the molding process before the component is installed. By pre-forming the fixation protrusion as part of the molding operation, the structure is prepared for component attachment without requiring subsequent operations that would compromise fiber continuity or structural strength.
2Ease of operation
If projections are formed by deforming the molded body after curing, then component support is achieved, but fiber continuity may be compromised
Solution Approach 1:
The projection is formed by temporarily heating the thermoplastic resin to above its glass transition temperature, changing its physical state from rigid to pliable. This allows the resin to be deformed into the projection shape while the fiber reinforcement maintains its continuity and structural integrity throughout the process.
Solution Approach 2:
The hollow structure utilizes a composite material system where continuous fibers are embedded in a thermoplastic resin matrix. The thermoplastic nature of the matrix allows for post-molding deformation while the continuous fibers maintain structural integrity, enabling projection formation without compromising fiber continuity.
3Ease of manufacture
If the thermoplastic resin is heated to form projections, then the resin melts and deforms to create support structures, but energy is consumed
Solution Approach 1:
Heating is applied locally to specific regions of the hollow structure where projections are needed, rather than heating the entire structure uniformly. This localized thermal treatment minimizes energy consumption while achieving the necessary resin softening for projection formation in the required areas.
Solution Approach 2:
The thermoplastic resin undergoes a phase transition from solid to a pliable state above its glass transition temperature, allowing deformation into projections. This phase change enables easy shaping with reduced force requirements, and the resin returns to its solid state upon cooling, locking in the projection geometry.
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 allows for easy fixation of components within hollow structures without breaking fibers, enhancing energy absorption and maintaining structural strength, while simplifying the manufacturing process.
Implementation Method 1
heating, while maintaining continuity of a fiber in an axial direction of the molded body and continuity of a fiber in a circumferential direction around an axis of the molded body, at least a portion of the molded body to melt the thermoplastic resin
Implementation Method 2
heating at least a portion of the molded body to melt the thermoplastic resin, deforming the at least a portion of the molded body that has been melted
Data Source
AI summary
A method of manufacturing a vehicle-body structural component includes: forming a cylindrical molded body made of a fiber-reinforced resin by molding a continuous fiber impregnated with a thermoplastic resin into a cylindrical shape and curing the thermoplastic resin; disposing a component in a space on an inner peripheral side of the molded body; and heating at least a portion of the molded body to melt the thermoplastic resin while maintaining continuity of a fiber in an axial direction of the molded body and continuity of a fiber in a circumferential direction around an axis of the molded body, deforming the at least a portion of the melted molded body from an outer peripheral side toward the inner peripheral side of the molded body to form projections projecting toward the inner peripheral side so as to come into contact with the component, and then curing the thermoplastic resin again.