Fluted CMC Sandwich Core for Aerospace Load-Carrying
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Solution Overview
Problem
Current ceramic matrix composite (CMC) structures used in aerospace applications are either too heavy due to the need for thick materials to carry loads or have weak core materials in sandwich constructions, making them unsuitable for lightweight, load-carrying structures.
Innovation Solution
A CMC sandwich construction featuring a load-carrying fluted core formed from ceramic matrix composite materials, where the core is composed of flutes that can be filled with high-temperature materials and are arranged in a nested, side-by-side relationship between ceramic facesheets, allowing for the transmission of compression and shear loads while maintaining a lightweight design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If CMC monocoque structures use thicker materials to carry loads, then load-carrying capability is improved, but weight increases
Solution Approach 1:
The structure is segmented into a sandwich construction with separate facesheets and core, where the core is divided into fluted elements. This segmentation allows the load-carrying function to be distributed efficiently, with facesheets handling bending stresses and the fluted core providing shear resistance and structural support, achieving high strength-to-weight ratio
Solution Approach 2:
The invention uses composite material architecture combining CMC facesheets with a CMC fluted core structure. This composite construction integrates different functional elements (facesheets for strength, fluted core for shear resistance and lightweight support) to achieve superior load-carrying capability per unit weight compared to monolithic CMC structures
2Weight of moving object
If CMC tile/foam sandwich constructions use weak core materials, then weight is reduced, but load-carrying capability deteriorates
Solution Approach 1:
The core structure employs fluted elements with specific geometric configurations (trapezoidal or triangular cross-sections) that concentrate material where structurally necessary. The fluted design provides localized reinforcement for shear load resistance while maintaining overall lightweight characteristics, overcoming the weakness of conventional foam cores
Solution Approach 2:
The invention changes the structural parameters of the core from conventional foam to fluted CMC elements with specific dimensional ratios and geometries. This parameter optimization enables the core to carry shear loads effectively while maintaining low weight, transforming the core from a weak supporting element to an active load-carrying component
3Ease of manufacture
If conventional sandwich structures use non-load-carrying cores, then manufacturing is simplified, but structural strength deteriorates
Solution Approach 1:
The fluted core is manufactured as separate modular elements that can be independently formed and then assembled between facesheets. This segmentation simplifies manufacturing by allowing core elements to be produced using standard ceramic forming techniques and then integrated into the sandwich structure, maintaining ease of manufacture while achieving load-carrying capability
Solution Approach 2:
The fluted core elements are nested between the facesheets in a structured arrangement where multiple flutes are positioned side-by-side. This nesting configuration allows the core to provide distributed shear resistance across the structure while maintaining a straightforward assembly process, combining structural enhancement with manufacturing simplicity
Data Source
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AI summary
A ceramic matrix composite structure (10) includes a load carrying fluted core (16) formed from a ceramic matrix composite. The fluted core (16) includes a plurality of nested flute members (18a, b) laminated between a pair of ceramic matrix composite facesheets (12, 14). The flute members (18a, b) are fabricated by wrapping ceramic resin fabric around a mandrel, curing the flute members (18a, b) and then removing the mandrels. The structure may include reinforced areas in which the facesheets (12, 14) are laminated directly together to receive fasteners for mounting the structure. The structure may include both flat and curved portions (Fig. 2).