Weldable Laminate Sheet Structure for Viscoelastic Core Joining
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Solution Overview
Problem
Welding of laminate sheets with viscoelastic cores poses challenges due to liquefying or vaporizing of the core material, leading to contamination and porosity in the weld, which decreases durability and integrity, and requires additional treatments for noise-vibration-harshness (NVH) management, increasing weight and cost.
Innovation Solution
A laminate sheet design with adhered and non-adhered regions, where the core layer is absent in the non-adhered region, allowing for welding without heat transfer to the core, maintaining its integrity and preventing contamination, and enabling selective stiffening without increasing complexity or weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is performed on laminate sheet with viscoelastic core, then metal sheets can be joined, but core layer liquefies and vaporizes causing weld contamination and porosity
Solution Approach 1:
The core layer is selectively removed from the weld zone to create a non-adhered region. This extraction of the harmful viscoelastic material from the welding area prevents contamination and porosity, allowing clean metal-to-metal welding while preserving the core layer in non-weld zones for damping functionality.
Solution Approach 2:
The laminate sheet is divided into adhered regions (with core layer for damping) and non-adhered regions (without core layer for welding). This segmentation allows different functional requirements to be met in different zones: vibration damping where needed and clean welding where joints are required.
2Object-affected harmful factors
If core layer is present in entire laminate sheet, then NVH performance is improved, but welding becomes impossible due to contamination
Solution Approach 1:
The core layer is applied selectively only in specific adhered regions rather than uniformly across the entire sheet. This local quality approach ensures that damping properties are present where vibration control is needed, while weld zones remain free of viscoelastic material to enable proper welding.
3Object-affected harmful factors
If additional damping treatments are added to monolithic sheet, then NVH performance is improved, but weight and cost increase
Solution Approach 1:
The laminate sheet itself functions as a composite structure with metal sheets providing structural strength and a viscoelastic core layer providing damping. This integrated composite design eliminates the need for separate damping treatments, reducing both weight and complexity compared to adding damping patches or coatings to monolithic metal sheets.
4Strength
If complex features are added to increase stiffness, then structural performance is improved, but packaging space and feature complexity increase
Solution Approach 1:
The laminate structure provides enhanced stiffness-to-weight ratio compared to monolithic sheets, allowing simpler geometric features to achieve the same structural performance. The composite nature of the laminate reduces the need for complex reinforcing features while meeting stiffness requirements.
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
The laminate sheet provides improved NVH performance, reduced weight, and enhanced stiffness and durability by preventing core material contamination during welding, while allowing for localized stiffening without additional features or weight, thus maintaining structural integrity and reducing manufacturing complexity.
Implementation Method 1
A laminate sheet made of metal sheets including a viscoelastic core disposed therebetween
Implementation Method 2
The core layer can be characterized by one or more of adhesive, acoustic, and viscoelastic properties
Implementation Method 3
The core layer can be characterized by one or more of adhesive, acoustic, and viscoelastic properties
Data Source
AI summary
A laminate sheet including a weldable margin is formed by laminating metal sheets having a core layer disposed therebetween. The core layer is formed of a core material which includes one or more of a viscoelastic, adhesive and acoustic material. The core layer is selectively distributed such that the laminate sheet includes an adhered region providing a laminate structure, and a non-adhered region including a weldable margin. The non-adhered region is adjacent an edge of the core layer and is characterized by a gap between the first and second metal sheets and by an absence of the core layer in the gap. The non-adhered region defines a weldable margin adjacent a core edge configured such that a weld is formable in the weldable margin without heat affecting the core layer. The laminate sheet can be joined by fasteners installed in the non-adhered region.