Variable Thickness Sheet Metal Container Design

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Solution Overview

Problem

Containers used for transportation, particularly sea freight, have high tare weights that increase fuel consumption, draft, and reduce payload capacity, necessitating a solution for reducing weight while maintaining stability and mechanical properties.

Innovation Solution

The container design incorporates beams and panels with variable sheet metal thickness, where end sections have greater thickness than intermediate sections, allowing for targeted material reduction in low-stress areas, and using recrystallization annealing or strain hardening to enhance strength and deformability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If containers are made with uniform thick sheet metal to ensure stability and strength, then mechanical properties and stability are improved, but weight increases leading to higher fuel consumption and reduced payload capacity

Engineering Contradiction:
Improvemechanical propertiesVSAvoidtare weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies local quality by varying the sheet metal thickness according to the local stress distribution in the container structure. Thicker sheets are used in high-stress areas such as corner posts, end walls, and regions near openings, while thinner sheets are used in low-stress areas like the middle sections of side walls and roof. This localized differentiation maintains structural strength where needed while reducing weight in non-critical areas, directly resolving the contradiction between strength and weight.

Inventive Principle:
Principle #3Local quality

2Weight of moving object

If sheet metal thickness is reduced to decrease container weight, then fuel consumption and draft are reduced, but stability and mechanical properties deteriorate

Engineering Contradiction:
Improvetare weightVSAvoidstability
Core Design Contradiction:
Weight of moving objectVSStability of the object's composition

Solution Approach 1:

The patent ensures stability by concentrating thicker sheet metal in critical structural zones that bear the primary loads and maintain container integrity. The variable thickness design preserves stability in high-stress regions while allowing weight reduction in areas where thickness is less critical for overall stability, thus resolving the contradiction between weight reduction and stability maintenance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs composite construction by combining sheet metal elements of different thicknesses within the same container structure. This composite approach allows the integration of thick and thin sections to create an optimized structure that maintains stability through strategic placement of thicker materials while achieving overall weight reduction, directly addressing the stability-weight contradiction.

Inventive Principle:
Principle #40Composite materials

3Strength

If uniform thick sheet metal is used throughout the container, then structural strength is maintained, but manufacturing costs and material usage increase

Engineering Contradiction:
Improvestructural strengthVSAvoidmaterial usage
Core Design Contradiction:
StrengthVSLoss of substance

Solution Approach 1:

The patent reduces material usage by applying the local quality principle, which dictates that sheet metal thickness should match the local structural requirements. Thicker materials are used only where structurally necessary (corner posts, end walls, high-stress zones), while thinner materials are used in low-stress areas. This localized optimization maintains structural strength throughout the container while significantly reducing overall material consumption and manufacturing costs.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies parameter changes by varying the sheet metal thickness parameter across different regions of the container rather than using a uniform value. This parameter optimization allows the structure to maintain required strength levels while minimizing material usage, as the thickness parameter is adjusted to match the stress distribution pattern, reducing waste in low-stress areas.

Inventive Principle:
Principle #35Parameter changes

4Weight of moving object

If variable thickness sheet metal is used to reduce weight, then payload capacity increases, but manufacturing complexity increases

Engineering Contradiction:
Improvetare weightVSAvoidmanufacturing complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The patent manages manufacturing complexity by implementing variable thickness through practical production methods such as welding different thickness sheets or using progressive rolling techniques. The design follows standard structural patterns where thickness variations occur at predictable locations (corners, ends, midsections), allowing for standardized manufacturing processes rather than completely custom fabrication, thus balancing weight reduction benefits with manageable manufacturing complexity.

Inventive Principle:
Principle #3Local quality

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 design results in a lighter container with improved stability and reduced manufacturing and operational costs, enabling increased payload capacity and fuel savings during transportation.

Implementation Method 1

at least one of the sheet metal elements is recrystallized at least in sections with a smaller sheet thickness

Methodology Applied
Scientific EffectRecrystallization annealing: Annealing

Implementation Method 2

or strain hardening to enhance strength and deformability

Methodology Applied
Scientific EffectStrain hardening: Plasticity

Data Source

PatentEP2881339B1Container and method for producing a container
Publication Date: 2017.08.02 MUHR UND BENNDER KG
  • EP2881339B1 patent drawingFigure 1~2
  • EP2881339B1 patent drawingFigure 3~5
  • EP2881339B1 patent drawingFigure 6~7

AI summary

The invention relates to a container comprising supports 2 and panels 3, wherein at least one element of the supports 2 and panels 3 is made of sheet metal with a variable sheet thickness over the longest length of the element. The invention further relates to a method for manufacturing such a container 1.