Split Metal Collar Expansion for Stable FRP Hole Fastening
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for attaching a metal collar to an FRP member using adhesive are prone to creep deformation, leading to changes in the positional relationship between the FRP member and the to-be-fastened object over time, which can cause damage to the reinforced fibers and increased frictional forces during the attachment process.
Innovation Solution
A fastening part structure that includes a metal collar with a first and second collar member, where the second collar member applies a pressing force to the first collar member to deform it for diameter expansion, reducing the adhesive layer thickness and minimizing frictional forces on the FRP member's surface, thereby preventing fiber damage and creep deformation influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gap between the metal collar and hole inner circumferential surface is made small to reduce adhesive layer thickness, then the influence of adhesive creep deformation is suppressed, but the frictional force during insertion increases causing damage to reinforced fiber
Solution Approach 1:
The metal collar is divided into two separate collar members that can be assembled together. The first collar member is inserted into the through-hole with a smaller outer diameter to minimize frictional force and prevent fiber damage, while the second collar member is attached afterward to provide the necessary pressing force that stabilizes the adhesive bond and suppresses creep deformation over time.
Solution Approach 2:
The first collar member is inserted into the through-hole before the second collar member is attached. This preliminary insertion allows the collar to be positioned with minimal frictional force on the fiber, and subsequent attachment of the second collar member provides the pressing force needed to stabilize the bond without requiring high insertion force.
2Reliability
If adhesive layer thickness is reduced to suppress creep deformation, then positional stability is improved, but the insertion process requires higher frictional force acting on the hole inner circumferential surface
Solution Approach 1:
The metal collar is divided into two separate collar members that can be assembled together. The first collar member is inserted into the through-hole with a smaller outer diameter to minimize frictional force and prevent fiber damage, while the second collar member is attached afterward to provide the necessary pressing force that stabilizes the adhesive bond and suppresses creep deformation over time.
Solution Approach 2:
The first collar member acts as an intermediary that facilitates easy insertion into the through-hole with minimal frictional force. After insertion, the second collar member is attached to provide the pressing force, effectively separating the insertion function from the pressing function to avoid high frictional forces during insertion.
3Ease of operation
If a single metal collar is used with adequate gap for adhesive, then insertion is easier, but adhesive creep deformation causes positional relationship changes over time
Solution Approach 1:
The metal collar is divided into two separate collar members that can be assembled together. The first collar member is inserted into the through-hole with a smaller outer diameter to minimize frictional force and prevent fiber damage, while the second collar member is attached afterward to provide the necessary pressing force that stabilizes the adhesive bond and suppresses creep deformation over time.
Solution Approach 2:
The first collar member is inserted into the through-hole before the second collar member is attached. This preliminary insertion allows the collar to be positioned with minimal frictional force on the fiber, and subsequent attachment of the second collar member provides the pressing force needed to stabilize the bond without requiring high insertion force.
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 solution effectively prevents damage to the reinforced fibers and minimizes the influence of creep deformation, ensuring a stable and secure attachment of the metal collar to the FRP member while reducing frictional forces and maintaining positional integrity over time.
Implementation Method 1
deforms the first collar member for diameter expansion with the pressing force, and presses the outer circumferential surface against the hole inner circumferential surface
Implementation Method 2
The metal collar is bonded and fixed to the FRP member with an adhesive applied in a gap between the outer circumferential surface of the metal collar and a hole inner circumferential surface
Implementation Method 3
the insertion of the metal collar into the through-hole is more likely to be associated with a frictional force in an inserting direction of the metal collar acting on the hole inner circumferential surface
Data Source
AI summary
A metal collar attached in a through-hole of FRP member includes first and second collar members. The first collar member includes outer and inner circumferential surfaces. The outer circumferential surface is in contact with a hole inner circumferential surface of the through-hole. A slit is formed in a part in a circumferential direction of the first collar member. The second collar member applies a pressing force radially outward to at least a part of the inner circumferential surface of the first collar member or a pressing force to inner surfaces of the slit in a direction in which the inner surfaces separate from each other in the circumferential direction. The second collar member is held in the first collar member by reaction of the pressing force, deforms the first collar member for diameter expansion with the pressing force, and presses the outer circumferential surface against the hole inner circumferential surface.