Aluminum Riveted Assemblies for Corrosion-Free Multi-Material Joining
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for joining dissimilar materials like aluminum, magnesium, and steel in multi-material assemblies face challenges such as galvanic corrosion, recycling issues, and increased costs due to the use of steel rivets, and resistance spot welding is not feasible due to melting point and solubility differences.
Innovation Solution
The use of aluminum or aluminum alloy rivets with high strain rate riveting techniques, which involve an impulsive load to form a mechanical interlock between components, reducing processing time and avoiding galvanic corrosion while maintaining performance and compatibility with existing body shop operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steel rivets are used to join dissimilar materials (aluminum, magnesium, steel), then the components can be mechanically fastened together, but galvanic corrosion occurs due to differences in galvanic potentials
Solution Approach 1:
The patent applies homogeneity by using aluminum alloy rivets to join aluminum alloy components, ensuring the fastening material is of the same or similar material type as the components being joined. This eliminates galvanic potential differences between the rivet and aluminum components, preventing galvanic corrosion while maintaining mechanical fastening strength.
2Ease of manufacture
If conventional resistance spot welding is used to join multi-material assemblies, then joining can be achieved, but the process is not feasible due to melting point differential, galvanic potential and solubility issues
Solution Approach 1:
The patent replaces the thermal welding process (resistance spot welding) with a mechanical fastening process (aluminum alloy rivet insertion and deformation). This substitution avoids the melting point differential issues that prevent welding of dissimilar materials, while achieving secure joining through mechanical interlocking and deformation of the rivet within the component holes.
Solution Approach 2:
The patent changes the joining mechanism from thermal (welding) to mechanical (riveting), and changes the rivet material parameter from steel to aluminum alloy. This parameter change eliminates the fundamental incompatibilities of welding dissimilar materials (melting point differences, galvanic potential, solubility issues) while achieving effective joining through controlled plastic deformation of the aluminum alloy rivet.
3Strength
If coated boron steel self-piercing rivets are used to join aluminum and steel, then the components can be fastened, but corrosion issues arise due to galvanic potentials and recycling becomes problematic
Solution Approach 1:
The patent uses aluminum alloy rivets that are homogeneous with the aluminum alloy components being joined, eliminating galvanic corrosion issues that arise from dissimilar material contacts. This also facilitates recycling since aluminum can be readily recycled without the complications of dissimilar metal combinations, unlike steel rivets joined to aluminum components.
4Weight of moving object
If high strength steel and aluminum alloys are used for lightweighting, then vehicle mass reduction is achieved, but new joining techniques are required to address material compatibility issues
Solution Approach 1:
The patent changes the rivet material parameter from traditional steel to aluminum alloy, which is compatible with the lightweighting strategy using aluminum and high strength steel components. This parameter change enables joining of lightweight multi-material assemblies without the galvanic corrosion and recycling issues of steel rivets, while maintaining the vehicle mass reduction 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
This approach enables efficient joining of multi-material assemblies with reduced galvanic corrosion, cost, and recycling challenges, while maintaining performance and safety, and supports the goal of lightweighting in the automotive industry by allowing for the use of novel low-density, high-strength material combinations.
Implementation Method 1
projecting the rivet through at least the first sidewall of the first component at a high strain rate to form a mechanical interlock between the components
Implementation Method 2
The tool can include a striker bar and a charge to propel the rivet
Data Source
AI summary
Riveted assemblies are provided that can include: a first component having opposing first and second sidewalls; a second component having opposing third and fourth sidewalls, wherein the second sidewall of the first component abuts the third sidewall of the second component to bind and form an affixing interface comprising the second and third sidewall between the first component to the second component; and a rivet extending between a head along a shank to an end, the rivet piercing the first sidewall with the end of the rivet being between the first and fourth sidewalls. Methods for affixing at least two components using a rivet are also provided. The methods can include: providing a first component having opposing first and second sidewalls; providing a second component having opposing third and fourth sidewalls; abutting the second sidewall of the first component to the third sidewall of the second component; providing a rivet extending between a head along a shank to an end; projecting the rivet through at least the first sidewall of the first component to form an affixing interface comprising the second and third sidewalls.