Sandwich Structure Dimensioning for Weight and Stiffness

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Solution Overview

Problem

The complexity of sandwich structures makes it difficult to dimension them effectively to achieve specific targets such as tensile strength, bending stiffness, and surface mass, particularly when using lighter metal alternatives like aluminum or composites.

Innovation Solution

A method for manufacturing sandwich structures with two steel skin layers separated by a polymeric layer, where the structure is dimensioned by defining target values and tolerance, and optimizing the thickness of the steel and polymeric layers, along with their intrinsic properties, to achieve the desired performance within defined operating ranges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If sandwich structures are used to reduce weight, then weight reduction is achieved, but dimensioning becomes difficult

Engineering Contradiction:
Improvevehicle weightVSAvoiddimensioning complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by systematically varying the thickness of steel skin layers and polymeric core layers, along with adjusting material properties such as Young's modulus and density, to achieve target mechanical properties. This allows precise control of the sandwich structure's performance while maintaining weight reduction benefits.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining steel skin layers with a polymeric core layer to create a sandwich structure that achieves optimal strength-to-weight and stiffness-to-weight ratios. This composite approach enables weight reduction while simplifying dimensioning through defined material combinations.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If multiple variables are optimized to achieve target values, then manufacturing precision is improved, but the number of parameters to control increases

Engineering Contradiction:
Improvetarget value attainmentVSAvoidnumber of variables
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the dimensioning process into distinct steps: defining target values for mechanical properties, determining operating ranges for each variable, selecting specific materials within those ranges, and manufacturing. This segmentation makes the complex multi-variable optimization manageable and systematic.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent systematically explores combinations of parameters (steel thickness, polymeric layer thickness, Young's modulus, density, volume ratio) to identify operating ranges that guarantee target value attainment. This structured parameter exploration transforms a complex optimization problem into a systematic design procedure.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11046054B2Method for producing a sandwich structure
Publication Date: 2021.06.29 ARCELORMITTAL SA

AI summary

A process for manufacturing a sandwich structure including two steel skin layers separated by a polymeric layer is provided. The process includes dimensioning the sandwich structure according to a target to be attained by defining the target to be attained by three target values, i.e., tensile strength Tc expressed in kN/mm, bending stiffness Bc expressed in kN/mm, and surface mass Mc expressed in Kg/m2, defining a tolerance for the attainment of target values, defining the sandwich structure by five variables, i.e., the thickness Ea of the steel skin layers expressed in mm, the polymeric layer thickness Ep expressed in mm, the intrinsic Young's modulus Yp of the polymeric layer, the intrinsic density dp of the polymeric layer, and the volume ratio Rp of the polymeric layer expressed as a volume percentage of the polymeric layer of the material, identifying the Ea, Ep, Yp, dp, and Rp combinations enabling attainment of the target values having the defined tolerance, and determining, for each variable, an operating range. The process also includes selecting the steel and the polymeric layer for which each variable is within the range defined in the previous step and manufacturing the corresponding sandwich structure.