Composite Ramp with Segmented Fabric Stacking for Stringer Integration
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Solution Overview
Problem
Aeronautical structures with ramps face limitations in gradient design due to the capabilities of Automatic Tape Lay-Up machines, leading to increased weight and manufacturing challenges when integrating reinforcement elements like stringers on composite material parts, such as aircraft wing skins, with significant thickness differences.
Innovation Solution
A composite material part design featuring a ramp with specific thickness zones and a longitudinal reinforcement element, where fabrics are stacked to create a gradient of 1/p, allowing the stringer to be situated on the ramp with a 1/(p/2) gradient, optimizing weight and curing processes by using ATL processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ATL machines are used to manufacture composite parts with ramps, then manufacturing precision is maintained within machine capabilities, but the gradient of the ramp is limited to lower values than design requirements
Solution Approach 1:
The ramp structure is divided into multiple thickness zones (first thickness zone and second thickness zone) with different fabric stacking sequences. The first zone has a gradient suitable for ATL manufacturing, while the second zone provides the steeper gradient needed for stringer placement, effectively segmenting the gradient requirement across zones.
Solution Approach 2:
Different zones of the ramp are assigned different fabric stacking characteristics - the first thickness zone uses a specific fabric arrangement to achieve gradient 1/p, while the second thickness zone uses a different stacking sequence to achieve gradient 1/(p/2), allowing each zone to have optimized local properties for its specific function.
2Ease of manufacture
If the ramp gradient is increased to accommodate stringer placement, then stringer integration is facilitated, but ATL machine manufacturing capability is exceeded
Solution Approach 1:
The ramp is segmented into two thickness zones with different fabric stacking. The first zone provides a gentle gradient (1/p) that ATL machines can manufacture with precision, while the second zone provides a steeper gradient (1/(p/2)) that facilitates stringer placement, thus segmenting the gradient function to satisfy both manufacturing capability and ease of stringer integration.
Solution Approach 2:
The solution moves from a single-dimensional gradient approach to a two-dimensional zoning approach, where the ramp is characterized by both longitudinal gradient variation and transverse zone boundaries. This dimensional change allows the structure to accommodate stringers while remaining manufacturable by ATL machines.
3Device complexity
If a single thickness zone is used for the ramp, then manufacturing is simplified, but neither optimal weight nor stringer placement is achieved
Solution Approach 1:
The ramp is divided into two thickness zones with distinct fabric stacking sequences. This segmentation allows the first zone to provide structural support with a gentler gradient while the second zone optimizes weight and stringer placement with a steeper gradient, achieving both weight optimization and manageable complexity through functional zoning.
Solution Approach 2:
Each thickness zone is assigned specific local qualities through different fabric stacking sequences. The first zone has properties optimized for one function while the second zone has properties optimized for another function, allowing each local region to contribute optimally to overall part performance while maintaining reasonable manufacturing complexity.
4Reliability
If the ramp gradient is optimized for stringer placement, then reinforcement element integration is improved, but manufacturing complexity increases
Solution Approach 1:
The stacking configuration is segmented into two distinct thickness zones, each with its own fabric stacking sequence. The first zone uses a simpler stacking pattern suitable for ATL manufacturing, while the second zone uses a different pattern to achieve the steeper gradient for reliable stringer integration, thus segmenting the complexity to balance reliability and manufacturability.
Data Source
AI summary
Composite material part (11) with stringer (31) on ramp, manufactured from a stack of fabrics, which comprises at least one zone (13) with two sectors (17, 19) having a greater thickness than that of the surrounding zones and with the stringer (31) situated on an edge (21) of said zone (13) in which: a) each group of fabrics (27, 27′ . . . ; 29, 29′, . . . ) of said sectors (17, 19) has the dimensions to form on said edge (21) a ramp with an acceptable gradient 1/p so that the stringer (31) remains situated on the ramp; b) the stacking of the zone (13) is carried out firstly by placing the fabrics (27, 27′, . . . ) of the first sector (17) and on these the fabrics (29, 29′, . . . ) of the second sector (19) in such a way that in the coinciding section (35) of said edge (21) the gradient of the resulting ramp is 1/(p/2).