Composite Bonding via Porous Substrate Mechanical Interlock
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Solution Overview
Problem
Composite materials tend to dis-bond when secured to non-composite structures using traditional methods such as fasteners, adhesives, and epoxies, leading to a lack of durability in the bond.
Innovation Solution
A process involving the creation of a substrate with intentionally formed voids and passageways that allow for the introduction and curing of a flowable, curable substance, enhancing the bond strength between composite and non-composite materials through a mechanical interlock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional bonding methods (fasteners, adhesives, epoxies) are used to secure composite materials to non-composite structures, then the bonding process is simple and straightforward, but the bond strength and durability are insufficient causing dis-bonding
Solution Approach 1:
The substrate is designed with a porous structure containing multiple voids and passageways that allow curable fluid to penetrate and form mechanical interlocks with the composite material, significantly enhancing bond strength through physical anchoring rather than relying solely on adhesive properties
Solution Approach 2:
The bonding interface is extended from a two-dimensional surface contact to a three-dimensional volumetric interlock by creating voids and passageways that penetrate the substrate, allowing the curable fluid to form bonds throughout the substrate thickness rather than only at the surface
2Area of stationary object
If surface roughening methods (grit blasting, sanding, etching) are applied to the non-composite material, then the surface area for bonding is increased, but the surface preparation process becomes more complex and time-consuming
Solution Approach 1:
The porous structure with voids and passageways is pre-formed in the substrate before the bonding process, eliminating the need for post-manufacturing surface roughening operations. The curable fluid then naturally penetrates these pre-created channels during the bonding process itself
3Strength
If ultrasonic or hot-plate welding is used to enable crosslinking between surfaces, then bond strength is improved, but the manufacturing process becomes more complex and requires specialized equipment
Solution Approach 1:
The mechanical welding processes (ultrasonic or hot-plate welding) are replaced with a chemical curing process where a curable fluid penetrates the porous substrate and cures in-situ, forming strong bonds through chemical crosslinking without requiring specialized welding equipment or complex mechanical energy input
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 process significantly increases the pull-off strength and shear strength between composite materials and substrates, providing a more durable and reliable bond compared to traditional surface preparation methods.
Implementation Method 1
introducing the part to a flowable, curable substance which enters the pocket through the passageway; and curing the substance to create a bond between the first and second materials
Data Source
AI summary
A system and process for bonding involves a pocket made into one article is used to secure that article to another using a flowable, curable material (e.g., resin) which during saturation enters through a passageway and at least partially fills the void. When the article is cured, the article is bonded to another article to which resin has also been applied since the void (now containing cured material) is larger than the passageway.