Composite Lattice Structures for High Strength-to-Weight Aerospace Applications
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fiber-reinforced composites used in high-strength/low-weight applications, such as aerospace structures, are prone to failure modes like matrix splitting, buckling, and delamination, and their complex construction processes are expensive and time-consuming, often introducing surface imperfections that diminish strength.
Innovation Solution
A composite lattice structure formed by connecting face sheets with lattice members made of single or multiple contiguous fiber tows, where the fibers abut, weave through, or are interfused with the face sheets, and the assembly is infused with a matrix material to create a rigid structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fiber-reinforced composite construction is used for high-strength applications, then strength is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The composite structure is divided into a lattice framework of fiber tows forming the primary load-bearing structure, with matrix material segmented into discrete regions that fill only the necessary void spaces between lattice members rather than impregnating the entire structure. This segmentation allows complex geometries to be constructed from modular lattice elements
Solution Approach 2:
The matrix material is applied locally only in regions where structural support is needed, such as at lattice joint connections and in controlled void spaces, rather than uniformly throughout the entire composite structure. This local quality approach reduces manufacturing complexity while maintaining strength at critical locations
2Strength
If conventional composite construction methods are used, then strength can be achieved, but time-consuming manufacturing processes increase production time
Solution Approach 1:
The lattice framework of fiber tows is constructed in advance as a pre-formed structural skeleton before matrix material is introduced. This preliminary action allows the complex geometric arrangement of fibers to be established once, avoiding time-consuming step-by-step impregnation processes while maintaining strength through the pre-configured load paths
Solution Approach 2:
The matrix material is extracted from the conventional continuous impregnation approach and applied only as discrete localized regions filling specific voids between lattice members. This extraction eliminates time-consuming full-structure infusion processes while maintaining necessary structural integrity
3Adaptability or versatility
If complex composite geometries are manufactured, then design flexibility is improved, but surface imperfections increase leading to part failure
Solution Approach 1:
The structure is segmented into a discrete lattice framework where fiber tows form the primary geometry and matrix material is segmented into controlled regions. This segmentation isolates potential surface imperfections to localized matrix areas rather than allowing them to propagate through continuous impregnation of complex geometries, improving reliability while maintaining design flexibility
Solution Approach 2:
The lattice framework serves as a structural copy or template that defines the complex geometry without requiring the matrix material to conform to every surface detail. The fiber tow arrangement captures the essential load-bearing geometry, allowing matrix material to be applied in simpler, more controlled regions
4Strength
If full matrix infusion is used in composite structures, then structural integrity is improved, but weight increases
Solution Approach 1:
The matrix material is applied with local quality, providing structural integrity only in specific regions where needed such as at lattice joint connections and in controlled void spaces between members. This localized application maintains structural integrity at critical locations while minimizing the total volume of heavy matrix material, thereby reducing overall structure weight
Solution Approach 2:
The lattice framework creates an inherent porous structure with controlled void spaces that are selectively filled with matrix material. This porous architecture allows the structure to maintain integrity through the fiber framework itself, requiring matrix material only in discrete regions rather than full infusion, thus reducing weight while preserving necessary structural performance
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 method enhances the strength and reduces the weight of composite structures by minimizing the volume of matrix-infused sections, improving the strength-to-weight ratio and reducing the complexity-related risks of part failure.
Implementation Method 1
The fluid matrix material is interfused into the face sheets and bores and then cured to form a rigid matrix
Data Source
AI summary
A single-skinned composite lattice sandwich structure includes a face sheet, fiber stringers, and at least one fiber tow arranged in a lattice structure separating the face sheet and fiber stringers. The face sheet and at least the fiber tow(s) forming the lattice may be interfused with a matrix to form a contiguous composite structure. The fiber stringers may be formed of various materials for imparting different structural properties to the sandwich structure, including carbon fiber for tensile strength and lightness, metallic or other rigid material for imparting overall structural rigidity, shape-changing material or actuated material for providing actuated deformation of the structure, and may also include sensors.