Polyethersulfone-Stitched Preforms to Suppress Composite Microcracks
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Solution Overview
Problem
Fiber-reinforced composite materials using stitched reinforcing-fiber base materials are prone to microcrack formation, which deteriorates mechanical properties, particularly due to interfacial delamination between the stitching thread and the matrix resin, exacerbated by thermal shocks.
Innovation Solution
Incorporating a polyethersulfone fiber as the stitching thread in the stitched reinforcing-fiber base material, which dissolves or swells in the matrix resin, thereby controlling microcrack formation and enhancing chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a stitching thread is used to stitch reinforcing-fiber sheets, then the linearity of reinforcing fibers is improved and crimp is reduced, but microcracks occur around the stitching thread which deteriorate mechanical properties
Solution Approach 1:
A resin coating is applied as an intermediary layer between the stitching thread and the reinforcing-fiber sheets. This coating reduces the concentration of stress at the interface between the stitching thread and the resin matrix, thereby suppressing microcrack initiation and propagation while maintaining the fiber alignment benefits of stitching
Solution Approach 2:
The physical and chemical parameters of the stitching thread are modified by coating it with resin. This changes the interface properties between the stitching thread and the matrix resin, reducing interfacial delamination and microcrack formation while preserving the structural integrity provided by the stitching thread
2Ease of manufacture
If conventional stitching threads are used, then the stitching process is simple, but interfacial delamination occurs between the stitching thread and the matrix resin under thermal shock
Solution Approach 1:
The resin coating is applied to the stitching thread before the stitching process. This preliminary coating action ensures that when the stitching thread is inserted and tensioned, the resin is already in place to prevent interfacial delamination during subsequent thermal shock and curing processes
Solution Approach 2:
The stitching thread is transformed into a composite structure by coating it with resin. This composite stitching thread combines the mechanical strength and fiber alignment capability of the stitching thread with the adhesion and stress-distribution properties of the resin coating, preventing interfacial delamination
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 use of polyethersulfone stitching thread significantly reduces microcrack formation, maintaining high mechanical properties and chemical resistance in the fiber-reinforced composite material.
Implementation Method 1
a polyethersulfone fiber as the stitching thread in the stitched reinforcing-fiber base material, which dissolves or swells in the matrix resin
Implementation Method 2
a polyethersulfone fiber as the stitching thread in the stitched reinforcing-fiber base material, which dissolves or swells in the matrix resin
Data Source
AI summary
The present invention provides a stitched reinforcing-fiber base material comprising a reinforcing-fiber base material composed of reinforcing fiber and a stitching thread comprising polyethersulfone fiber, the stitched reinforcing-fiber base material being characterized in that the reinforcing-fiber base material is stitched with the stitching thread.