Can Bottom Dome Structure Against Drop-Induced Inversion
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Solution Overview
Problem
Existing can containers with dome-shaped bottoms experience inversion due to water hammer phenomena during falls, especially when made of aluminum alloys with reduced thickness, leading to issues with falling strength and pressure resistance.
Innovation Solution
The can container features a dome part with a central dome part and an outer peripheral dome part, where the outer peripheral dome part has a smaller radius of curvature than the central dome part, and an annular convex part providing additional support. The shape is achieved through a specific forming process using tools with curved surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the thickness of the container is reduced to reduce raw materials and weight, then weight and material usage are reduced, but strength and falling resistance deteriorate
Solution Approach 1:
The dome part is designed with non-uniform thickness distribution, where the thickness is greater at the outer peripheral edge and smaller at the central part. This local quality variation allows the container to maintain high falling strength at the impact-prone outer edge while using less material overall, thus reducing weight without sacrificing strength.
Solution Approach 2:
The dome part is formed with a curved spherical shape instead of a flat bottom. This curvature distributes stress more effectively during impact, enhancing falling strength. The specific radius of curvature is optimized to balance material usage and strength requirements.
2Volume of moving object
If the radius of curvature of the dome part is increased to secure container volume, then volume is maintained, but falling strength deteriorates due to easier dome inversion during falls
Solution Approach 1:
The dome part employs varying thickness across its surface - thicker at the outer peripheral edge for impact resistance and thinner at the center for volume optimization. This local quality differentiation allows the container to maintain adequate volume while preventing dome inversion during falls by reinforcing the critical outer edge region.
3Strength
If the second concave curved surface part with small radius of curvature is added to the dome part, then falling strength should be improved, but the dome part becomes more prone to inversion due to water hammer phenomenon
Solution Approach 1:
The dome part is designed with a first concave curved surface part at the outer peripheral edge and a second concave curved surface part at the central region, each with different radius of curvature characteristics. The first part has larger curvature radius for stability, while the second part has smaller curvature radius for localized reinforcement, creating a gradient structure that balances falling strength and inversion resistance.
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 configuration enhances the falling strength and pressure resistance of the can container, reducing the likelihood of dome inversion during falls and improving the overall structural integrity, especially in thinner aluminum alloy materials.
Implementation Method 1
when plastic work is performed by pressing a forming tool having a working surface along a curved surface of the dome part against the dome part
Data Source
AI summary
A can container includes a can barrel and a can bottom; the can bottom includes a dome part which is concaved toward an inner side of the can container along a direction of a can axis at a center, and also includes an annular convex part which projects toward an outer side of the can container so as to shape an annular support part on an outer periphery of the dome part: and the dome part has a central dome part which is positioned on the can axis and has a set radius of curvature, and an outer peripheral dome part which is shaped continuously on an outer side of the central dome part, has a center of curvature positioned on the can axis, and has a radius of curvature smaller than the radius of curvature of the central dome part.