Composite Cone Layup for Void-Free Load Transmission
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Solution Overview
Problem
Conventional methods for fabricating cone-shaped composite structures require darting and overlap splicing, which increase weight and risk of voids or wrinkles, compromising the strength and load transmission capabilities of payload attach fittings for spacecraft.
Innovation Solution
A cone-shaped composite article with a quasi-isotropic layup pattern using unidirectional plies with fiber angles of 0, 90, +45, and −45 degrees, and an outer sublaminate with a mirror image stacking sequence, eliminating the need for darts and splices, and incorporating global axial plies for enhanced strength and stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If darting and overlap splicing are used to make composite plies conform to cone geometry, then the composite plies can be fabricated, but the weight of the composite structure increases
Solution Approach 1:
Instead of cutting darts or overlapping plies to fit the cone geometry, the patent inverts the approach by making the plies continuous and allowing them to wrap around the cone. The ply layout is designed to naturally conform to the conical surface without requiring traditional joining or cutting methods, thereby eliminating the weight penalty associated with darts and splices.
2Ease of manufacture
If darting and overlap splicing are used to make composite plies conform to structure geometry, then the composite plies can be fabricated, but the risk of voids or wrinkles increases
Solution Approach 1:
The patent eliminates darting and overlapping operations that create voids and wrinkles by inverting the traditional approach. Continuous plies are used that wrap around the cone without requiring cutting or joining, thereby eliminating the primary sources of manufacturing defects that compromise structural integrity.
Solution Approach 2:
The patent maintains continuous fiber paths through the cone structure without interruption from darts or splices. This continuity ensures consistent load transfer and eliminates discontinuities where voids and wrinkles typically form, thereby improving the reliability and strength characteristics of the composite structure.
3Ease of manufacture
If conventional fabrication methods with darts and splices are used, then composite plies can conform to geometry, but the structural integrity is compromised
Solution Approach 1:
The patent inverts the conventional approach by using continuous plies that wrap around the cone without requiring darts or splices. This eliminates the weak points created by traditional joining methods and maintains full structural integrity throughout the load path.
Solution Approach 2:
The continuous fiber paths ensure uninterrupted load transmission through the cone structure. By eliminating darts and splices, the patent maintains consistent mechanical properties and strength characteristics throughout the entire structure, enabling reliable load transmission from spacecraft to launch vehicle.
Data Source
AI summary
A method of manufacturing a cone-shaped composite article may include providing unidirectional plies in a continuous arcuate shape in a flat pattern configured to wrap 360 degrees around a cone-shaped mandrel such that opposing ply ends of each unidirectional ply terminate at a ply seam. The method may further include laying up at least one inner sublaminate on the cone-shaped mandrel, the inner sublaminate containing at least four of the unidirectional plies having an inner stacking sequence with fiber angles of −45, 90, 0, +45 degrees such that the inner sublaminate has a quasi-isotropic layup at any location of the inner sublaminate. The method may additionally include laying up at least one outer sublaminate in an outer stacking sequence being a mirror image of the at least one inner stacking sequence.