Domed Two-Piece Metal Can Bottom for Buckling Resistance
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Solution Overview
Problem
Existing metal cans fail to effectively enhance the strength of the domed bottom section while maintaining a stable diameter and reducing thickness, leading to potential buckling under internal pressure or impact loads.
Innovation Solution
A two-piece metal can design with a domed section comprising multiple arcuate portions, where the curvature radii of these portions are optimized to enhance strength, with a specific ratio between the first and second curvature radii ranging from -0.148 * Y + 0.025 * DP + 1.92 to 0.140 * Y - 0.054 * DP + 3.97, and a third curvature radius between 1.5 mm and 3.5 mm, ensuring stability and impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the dome part significantly protrudes upwardly to increase resistance against reversal load, then the strength of the dome part is enhanced, but the internal content volume of the can is reduced
Solution Approach 1:
The invention optimizes the curvature radius ratio parameter (Ra/Rb) of the dome part's arcuate sections to achieve the required strength without increasing the dome height. By adjusting this geometric parameter within a specific range (1.5-3.0), the dome part gains sufficient resistance against reversal load while maintaining an acceptable internal volume, thus resolving the contradiction between strength enhancement and volume preservation.
2Strength
If the curvature radius of the arc in the peripheral portion of the dome part is increased to enhance strength, then the strength is improved, but the dome part height must be increased which reduces internal volume
Solution Approach 1:
The invention changes the parameter relationship between the curvature radii of the central and peripheral arcs. Instead of simply increasing the peripheral curvature radius (which would increase dome height), the invention optimizes the ratio Ra/Rb to achieve strength enhancement through geometric optimization rather than dimensional increase, thus avoiding volume loss.
Solution Approach 2:
The invention utilizes the curvature characteristics of the dome part by defining it as composed of two arcuate sections with specific curvature radius relationship. This curvature-based design approach allows strength optimization through geometric parameters (Ra and Rb ratio) rather than through increasing the overall dome height, resolving the contradiction between strength and volume.
3Loss of substance
If the thickness of the metal can is reduced to save material and cost, then material usage is reduced, but the strength and resistance to buckling are compromised
Solution Approach 1:
The invention compensates for reduced material thickness by optimizing the geometric parameters of the dome part, specifically the curvature radius ratio Ra/Rb. This parameter optimization creates a more efficient stress distribution in the thinner material, allowing the can to maintain required strength and buckling resistance with reduced material usage, thus resolving the contradiction between material savings and strength maintenance.
Data Source
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AI summary
A two-piece metal can thinned without reducing the strength to save material, and a manufacturing method thereof. In a domed section 5, a first arcuate portion 5A having a first curvature radius Ra is joined smoothly to a second arcuate portion 5B having a second curvature radius Rb that is formed between the first arcuate portion and a counter section. A ratio between the first curvature radius Ra and the second curvature radius Rb (the first curvature radius / the second curvature radius) falls within a range between a lower limit value and an upper limit value expressed as: Lowerlimitvalue=−0.148⋅Y+0.025⋅DP+1.92; and Upperlimitvalue=0.140⋅Y−0.054⋅DP+3.97, given that a height of the domed section 5 from an outer circumferential end of the second arcuate portion 5B to the top portion 7 is Y, and that an outer diameter of the domed section 5 is DP.