Composite T-Reinforcement Delamination Prevention
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Solution Overview
Problem
Composite parts with T-shaped reinforcements, commonly used in aeronautics, face delamination issues due to stress-induced unfolding and mechanical weakening at junction zones, particularly when subjected to tensile forces, leading to premature failure and reduced structural integrity.
Innovation Solution
Incorporating a core with radially extending needles made of pultruded yarns that connect the sole and T-shaped reinforcement, preventing resin accumulation and deformation, and linking the L-shaped elements to enhance structural stability and prevent delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If L-shaped elements are used to form T-shaped reinforcement, then the part can be manufactured with composite material stacks, but the junction zone creates mechanical weakening leading to delamination under tensile forces
Solution Approach 1:
The reinforcement is divided into multiple L-shaped elements (first and second L-shaped elements) arranged back to back, with each element having distinct bases and ribs connected by angled portions. This segmentation allows the structure to be built from discrete composite stacks while distributing stress across multiple junction zones rather than a single continuous reinforcement piece.
Solution Approach 2:
A core element is introduced as an intermediary component housed within a cavity formed by the L-shaped elements and the sole. The core fills the junction zone cavity and provides internal support to prevent the unfolding of angled connecting portions under tensile loads, thereby preventing delamination without requiring additional external fastening mechanisms.
2Strength
If stitching is used to join folds together, then reinforcement is provided, but the wire tension is insufficient to prevent unfolding at the junction area
Solution Approach 1:
The core acts as a mediator element inserted into the cavity at the junction zone. It physically blocks the unfolding motion of the angled connecting portions by providing internal support from within the cavity, eliminating the need for external stitching wires that prove insufficient under tensile loads.
Solution Approach 2:
The core is positioned in advance within the cavity formed by the L-shaped elements before the part is subjected to operational loads. This preliminary placement ensures that the junction zones are pre-supported and protected against unfolding stresses from the very beginning of the part's service life, rather than relying on wire tension that develops only after deformation occurs.
3Ease of operation
If the part is deformed to tension the wire, then the wire can play its reinforcement role, but cracking and delamination occur that compromise part integrity
Solution Approach 1:
The core serves as an internal intermediary support that eliminates the need for wire tensioning through deformation. By providing structural support from within the junction zone cavity, the core prevents unfolding at low stress levels, thereby avoiding the deformation-induced cracking and delamination that would otherwise compromise part integrity.
Solution Approach 2:
The core is installed in advance to provide immediate structural support at the vulnerable junction zones. This preliminary reinforcement prevents the need for subsequent deformation operations to tension wires, thereby avoiding the harmful side effects of such deformation on part integrity from the outset.
Data Source
Figure 1~3
AI summary
The invention relates to a part (10) made from composite material, comprising a base (12) and a T-shaped reinforcement (14). The T-shaped reinforcement (14) comprises a first L-shaped element (16a) and a second L-shaped element (16b), each comprising a first right-angled connection portion (22a) and a second right-angled connection portion (22b) respectively. The part (10) is characterised in that it comprises a plurality of rods (26), each connecting the base (12) to the T-shaped reinforcement (14) of the part (10), close to the connection portions (22a, 22b) and extending in multiple directions so as to oppose, in particular, the separation of the base (12) from the T-shaped reinforcement (14).