Composite Stringer Splicing and Vacuum Compaction
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Solution Overview
Problem
The assembly of stiffened composite structures, such as aircraft fuselages, is labor-intensive and requires large, customized tooling, making it difficult to handle and transport long stringers and resulting in inefficient production processes.
Innovation Solution
The use of a trunnion with a rotatable chuck and stiffener trays allows for the indexing, splicing, and vacuum compaction of stringer segments, enabling efficient assembly and transportation of stringers in segments, and accommodating multiple stringer types with a single trunnion, along with a transfer tool for efficient loading onto an inner mold line layup mandrel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If stringers are handled and assembled in their entirety, then the structural integrity is maintained, but the handling and transportation becomes difficult due to their length
Solution Approach 1:
The stringer is divided into multiple segments that can be handled and transported separately. These segments are then joined together using a splice fixture to form the complete stringer assembly, combining the benefits of easier handling with maintained structural integrity.
2Manufacturing precision
If customized tooling is used for each stringer type, then the assembly precision is improved, but the device complexity and space requirements increase
Solution Approach 1:
A universal splice fixture is designed that can accommodate multiple stringer types through adjustable components and interchangeable fixtures. This single multi-functional device replaces the need for multiple customized tooling sets, maintaining assembly precision while reducing device complexity and space requirements.
3Ease of operation
If manual positioning of stringers is used, then the flexibility in positioning is maintained, but the productivity decreases due to labor-intensive processes
Solution Approach 1:
A splice fixture serves as an intermediary device that guides and positions stringer segments during assembly. This fixture maintains the positioning flexibility previously achieved through manual methods while enabling more efficient assembly operations and improving overall productivity.
4Length of moving object
If large tooling is used to accommodate long stringers, then the assembly capability is improved, but the space requirements increase
Solution Approach 1:
By segmenting the stringer into smaller sections, the assembly process can be performed on a compact splice fixture that occupies less space. The segments are joined in-place, eliminating the need for large tooling that could accommodate the full length of the completed stringer.
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
This method improves production efficiency by allowing for the assembly of stiffened composite structures with reduced labor and tooling requirements, enabling the handling and transportation of long stringers in segments and accommodating various stringer types, thus streamlining the manufacturing process.
Implementation Method 1
applying a vacuum chuck to the trunnion to compact the stiffener assembly
Implementation Method 2
moving the vacuum chuck together with the stiffener assembly from the trunnion to a transfer tool
Data Source
AI summary
Methods of assembling stiffened composite structures are disclosed. Some methods include forming a stiffener assembly by compacting it within a trough formed in a trunnion. A single trunnion may accommodate two or more different types of stiffeners, thereby avoiding the need for multiple sets of tooling. In some methods, a plurality of stiffener segments may be spliced together, thereby avoiding the need to transport and handle an entire stiffener. A vacuum chuck may be utilized in some examples to transfer the stiffener assembly from the trunnion to a transfer tool. The same vacuum chuck may be transferred along with the stiffener assembly on the transfer tool and loaded onto an inner mold line layup mandrel, where the vacuum chuck may be used to compact the stiffener assembly to the inner mold line layup mandrel.