Amorphous Metal Rivets for High-Strength Joints Without Pull-Out
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Solution Overview
Problem
Traditional rivets face challenges with high-strength alloys, leading to issues like excessive tensile and shear stresses, and pull-out from joints, due to the lack of suitable materials with improved properties for riveted joints.
Innovation Solution
The use of amorphous metal alloys, specifically bulk metallic glass (BMG), for rivets that can accommodate large elastic deformation, allowing for secure joining of metal plates with unique properties that enable elastic brad-type rivets to be compressed and inserted through holes, and bucked-type rivets to be thermoplastically deformed for secure positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional high-strength alloy rivets are used, then the rivet can provide sufficient strength, but the rivet experiences excessive tensile and shear stresses leading to pull-out from joints
Solution Approach 1:
The patent changes the material parameters of the rivet by using amorphous metal alloy instead of traditional crystalline alloys. This material parameter change enables the rivet to accommodate large elastic deformation (up to 2-3 times that of traditional rivets), allowing the joint to deform elastically under load rather than the rivet failing from excessive stress, thus resolving the contradiction between strength and joint reliability
Solution Approach 2:
The patent employs amorphous metal alloy, which represents a composite material structure at the atomic level (lacking long-range order while maintaining short-range order). This unique material structure provides both high strength and exceptional elastic deformation capability, enabling the rivet to maintain joint reliability under varying load conditions without pull-out failure
2Reliability
If amorphous metal alloy is used for rivets, then the rivet can accommodate large elastic deformation and reduce pull-out, but the manufacturing process becomes more complex requiring specialized forming methods
Solution Approach 1:
The patent utilizes the phase transition properties of amorphous metal alloy, specifically heating the rivet into the supercooled liquid region (between glass transition temperature Tg and crystallization temperature Tx) where the material becomes formable. This phase transition approach enables traditional forming processes to be applied to amorphous metal, resolving the manufacturing complexity while maintaining the reliability benefits
Solution Approach 2:
The patent applies preliminary heating to transform the amorphous metal rivet into a formable state before applying deformation forces. By pre-heating the rivet shaft to above Tg but below Tx, the material becomes sufficiently soft to be formed by conventional tools, then is rapidly cooled after forming to restore its high-strength amorphous structure, thus easing manufacturing while preserving joint reliability
3Strength
If amorphous metal rivets are used, then the rivet provides enhanced gripping power and reduced weight, but the rivet requires thermoplastic or elastic deformation processes for installation
Solution Approach 1:
The patent changes the temperature parameter during installation by heating the amorphous metal rivet into its supercooled liquid region, transforming it from a rigid state to a formable state. This parameter change enables the rivet to be deformed thermoplastically or elastically as needed, providing enhanced gripping power through controlled deformation while managing installation process complexity through temperature control
Solution Approach 2:
The patent exploits the dynamic mechanical properties of amorphous metal, which can transition from a rigid, high-strength state to a soft, formable state through temperature control, and back again. This dynamic behavior allows the rivet to be installed with controlled deformation (thermoplastic or elastic) and then lock in place with enhanced gripping power, balancing installation complexity with performance benefits
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 BMG rivets provide enhanced gripping power, reduced weight, and improved fatigue life, addressing failure modes like excessive stresses and pull-out, while allowing for secure assembly with access from one side, offering a viable alternative to welding and bolting.
Implementation Method 1
The anvil head is configured to plastically deform the formable member proximate to the second member
Implementation Method 2
amorphous metal alloys, specifically bulk metallic glass (BMG), for rivets that can accommodate large elastic deformation
Implementation Method 3
the formable member may be heated by exciting the anvil ultrasonically
Implementation Method 4
spinning the anvil rapidly across one or more surfaces of the formable member
Data Source
Figure 1~2B
Figure 3A~4
Figure 5~6
AI summary
A family of rivets including both blind and bucked-type rivets made at least partially from an amorphous metal alloy. A blind rivet includes a head portion and a tail portion. At least one of the head portion and the tail portion is configured to elastically deform to secure a first member in position relative to a second member. The head portion and the tail portion may include one or more deformable legs having an interface feature configured to engage with one of the first member and the second member. A bucked-type rivet assembly includes a formable member and an anvil. The anvil is configured to thermoplastically deform the formable member proximate to the second member by passing current through an electrical circuit that includes at least one of the formable member and anvil.