Rivet and Die Geometry for Crack-Resistant Dissimilar Material Joining
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional riveting techniques face challenges in joining dissimilar materials, resulting in joints with less-than-desired strength and potential cracking, due to limitations in rivet flaring and material compatibility, especially when working with materials like carbon-fiber thermoplastic composites.
Innovation Solution
A riveting system featuring a uniquely configured die and rivet that causes the rivet tip to flare outward and upward, forming a mechanical hook, which securely links adjacent workpieces, while a controller monitors the riveting process to ensure proper joint formation and alerts for any flaws.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional riveting techniques are used to join dissimilar materials, then the riveting process is simple, but the joint strength is insufficient and cracking occurs
Solution Approach 1:
The patent changes the geometric parameters of the rivet (length, diameter, tip angle) and the riveting process (force application, deformation control) to achieve a mechanical hook configuration that significantly improves joint strength while preventing cracking in dissimilar materials
Solution Approach 2:
The rivet is designed to form a curved mechanical hook configuration after deformation, where the distal tip curves back toward the workpiece. This curved geometry creates a locking mechanism that enhances joint strength and eliminates cracking by distributing stresses evenly
2Strength
If short rivets are used to avoid cracking, then cracking is reduced, but joint strength decreases
Solution Approach 1:
The patent transitions from considering only rivet length to incorporating the three-dimensional spatial configuration of the rivet, specifically the curvature and hook formation in the radial dimension. This allows the rivet to achieve locking engagement without requiring excessive length that would cause cracking
3Adaptability or versatility
If materials with high ductility are used to prevent cracking, then cracking is avoided, but material selection is limited
Solution Approach 1:
The patent replaces reliance on material ductility (material property) with a mechanical hook mechanism (structural configuration). The hook formation through controlled rivet deformation provides cracking prevention through geometric locking rather than material deformation capacity, enabling use of less-ductile materials
4Ease of manufacture
If traditional riveting is used for dissimilar materials, then the process is straightforward, but material compatibility issues arise
Solution Approach 1:
The patent modifies key parameters including rivet geometry (tip angle, diameter ratio), deformation force magnitude, and die configuration to accommodate dissimilar materials with different mechanical properties, ensuring reliable joining while maintaining process simplicity
Data Source
AI summary
A riveting system, for use in mechanically linking adjacent workpieces, including a rivet having a height greater than a sum of thicknesses, measured along a line of riveting, of the workpieces being linked, so that the rivet can pass fully through the workpieces. The system also includes a riveting die, which may be a separate product. The die includes a protrusion extending from a peak toward a transition point; and a trough having a trough surface. The trough surface includes a trough inner wall, extending from the transition point to a trough bottom, and a trough outer wall, extending from the trough bottom to a trough outer edge. The technology also includes computerized systems for comparing a load-displacement profile of riveting to a pre-set profile to determine whether the riveting was performed properly.