Fiber Reinforced Plastic Bolt Thread Strength via Prepreg Winding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fiber reinforced plastic (FRP) bolts have weak screw threads due to the cutting of reinforcing fibers during thread formation, leading to inadequate mechanical strength and high production costs associated with complex molding processes.
Innovation Solution
A method of forming a screw thread on a hardened prepreg layer with additional reinforcing fibers, which are wound around an internal fiber-reinforced body and then heat-hardened, ensuring the fibers remain intact and increase the thread's strength, while using a heat shrinkable film for efficient heat-hardening without the need for multiple molds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the surface of the FRP round bar is ground away to form the screw thread, then the screw thread is formed on the bolt, but the reinforcing long-fiber is cut off and the mechanical strength is deteriorated
Solution Approach 1:
The screw thread shape is pre-formed on the FRP round bar surface before the actual threading operation. This preliminary shaping allows the subsequent threading process to remove minimal material, preserving the reinforcing fibers and maintaining mechanical strength while still forming functional screw threads.
2Strength
If different materials are used for the internal body and screw thread with a molding process, then the strength of screw thread is increased, but the resin impregnation process and hardening process become complicated
Solution Approach 1:
The invention applies different material properties to different regions of the bolt: the internal body uses standard FRP composition while the screw thread region incorporates additional resin and fiber reinforcement. This localized differentiation increases thread strength without requiring complete redesign of the entire molding process.
3Ease of manufacture
If a molded preform made of thermoplastic resin is used, then the bolt can be formed with a screw thread, but the preform should be molded again which reduces productivity
Solution Approach 1:
The screw thread shape is pre-formed on the FRP round bar surface through a preliminary shaping operation before the final threading process. This eliminates the need for separate molding operations and allows direct formation of the final bolt product, significantly improving productivity.
4Manufacturing precision
If several molds are prepared for each type or size of the bolt, then the screw thread can be formed accurately, but the production cost increases and productivity decreases
Solution Approach 1:
The invention uses a universal FRP round bar as a base component that can be produced in large quantities through continuous pultrusion. Different bolt types and sizes can be created from this standard round bar through subsequent machining and threading operations, eliminating the need for dedicated molds for each bolt variant while maintaining manufacturing precision.
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 enhances the tensile strength and durability of the FRP bolt's screw thread and improves productivity by maintaining fiber integrity and simplifying the production process, resulting in a higher quality bolt with reduced production costs.
Implementation Method 1
heat-hardening the wound prepreg to form a fiber reinforced plastic round bar
Implementation Method 2
heat shrinkable film for efficient heat-hardening
Data Source
Figure 1A~3
Figure 4A~4B
AI summary
A fiber reinforced plastic bolt(FRP) and a method for producing the same are disclosed. The FRP bolt is useful in the industrial areas which require a bolt having electric-insulation, anti-corrosive, thermal- insulation, and non-magnetic properties. The method for producing the FRP bolt includes the steps of: winding a prepreg around a surface of an internal body, wherein the internal body includes a first reinforcing fiber which is unidirectionally aligned along the axis of the bolt, and a synthetic resin which is impregnated into the first reinforcing fiber, and the prepreg includes a second reinforcing fiber and a thermosetting resin which is impregnated into the second reinforcing fiber; forming a fiber reinforced plastic round bar by heat-hardening the prepreg; and forming a screw thread on the surface of the fiber reinforced plastic round bar.