Anticlastic Sandwich Core Structures for Mass Production
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Solution Overview
Problem
Current methods for manufacturing metallic honeycombs in mass production are cost-ineffective, and uni-directionally corrugated core structures in metal sandwich constructions suffer from delamination due to small bonding lands, leading to inferior weight-specific mechanical performance and direction-dependent mechanical properties.
Innovation Solution
The development of an optimized anticlastic sandwich core structure with periodically enlarged bonding lands, created using a pin structure from initially flat sheets through progressive stamping or roll embossing, allowing for enhanced shear force transmission and improved mechanical performance in two orthogonal directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic honeycomb structures are manufactured using conventional methods, then excellent bending stiffness to weight ratio is achieved, but cost-effective mass production is impossible
Solution Approach 1:
The patent employs a porous foam core material with controlled cellular structure to achieve the honeycomb-like mechanical properties. The foam core provides excellent bending stiffness to weight ratio while being manufacturable through conventional foam fabrication and bonding processes, resolving the contradiction between structural performance and mass production feasibility
Solution Approach 2:
The invention creates a composite sandwich structure combining face sheets with a porous foam core. This composite construction achieves the desired mechanical properties through the synergistic combination of materials, allowing mass production while maintaining excellent bending stiffness to weight ratio
2Ease of manufacture
If uni-directionally corrugated core structures are used in metal sandwich construction, then cost-effective production is achieved, but bonding land is too small to transmit full shear force
Solution Approach 1:
The patent introduces periodic bonding lands at specific locations (peaks and valleys of the corrugated structure) where the core contacts the face sheets. These localized bonding regions concentrate the shear force transmission capability at critical interfaces, ensuring adequate shear force transmission while maintaining cost-effective production of the corrugated core structure
Solution Approach 2:
The corrugated core structure is pre-formed with periodic peaks and valleys that create predetermined bonding lands before assembly. This preliminary structuring ensures adequate bonding surface area is available at critical locations to transmit full shear force, preventing delamination while maintaining manufacturing efficiency
3Ease of manufacture
If uni-directionally corrugated core structures are used, then production cost is reduced, but mechanical properties become direction-dependent with pronounced strong and weak directions
Solution Approach 1:
The patent employs a corrugated core structure with asymmetric periodic geometry featuring peaks and valleys. This asymmetric design creates different mechanical responses in different directions, but the periodic nature ensures predictable behavior that can be accounted for in design, maintaining cost-effectiveness while managing direction-dependent properties
Solution Approach 2:
The corrugated core structure exhibits periodic geometry with repeating peaks and valleys along its length. This periodic structure creates predictable mechanical behavior in both longitudinal and transverse directions, allowing the design to accommodate direction-dependent properties while maintaining manufacturing efficiency and cost-effectiveness
4Strength
If bonding land between corrugated core and face sheets is increased, then shear force transmission improves, but weight specific mechanical performance may be compromised
Solution Approach 1:
The patent concentrates bonding capability at specific periodic locations (peaks and valleys) rather than providing continuous bonding across the entire interface. This localized bonding approach increases shear force transmission at critical interfaces while minimizing the additional weight from bonding material, preserving weight-specific mechanical performance
Solution Approach 2:
The bonding lands are pre-positioned at the periodic peaks and valleys of the corrugated structure during core fabrication. This preliminary placement ensures adequate shear force transmission capability is built into the structure's geometry itself, reducing the need for additional bonding material and preserving weight efficiency
Data Source
AI summary
A sandwich structure is provided that includes a corrugated layer with at least one core layer (structure) made of a periodic array of adjacent truncated upward facing peaks and truncated downward facing valleys. Each truncated peak has a bonding land of an area A1. Each truncated valley has a bonding land of an area A2. A ratio of A1/A2 is less than 2. A distance D is between neighboring peaks, and a distance D is also between neighboring valleys. The corrugated layer is made from an initially flat sheet thickness of t. A first sheet layer is physically coupled to bonding lands of the truncated peaks. A second sheet layer is physically coupled to bonding lands of the truncated valleys.