Composite Blade Spar Preform Partial Vitrification
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Solution Overview
Problem
The mechanical strength at the interface between the spar and the blade preform in composite material blades, such as those used in turbojet engines, is not satisfactory, leading to potential deformation and bonding issues during manufacturing.
Innovation Solution
A method for manufacturing composite blades that involves preparing a spar preform with a core, partially polymerizing a first resin within the spar preform to achieve partial vitrification, and then injecting a second resin into a blade body preform around the spar. This process enhances the mechanical properties of the interface without the need for additional adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the first resin is fully polymerized before injection of the second resin, then the spar preform has sufficient structural stability, but the mechanical strength at the interface between the spar and blade preform deteriorates
Solution Approach 1:
The first resin is partially polymerized before the blade preform is positioned around the spar preform. This preliminary partial polymerization provides enough structural stability for handling and positioning, while leaving the resin in a state that will form a strong bond with the second resin, thereby resolving the contradiction between structural stability and interface strength.
2Ease of operation
If the first resin is fully polymerized, then handling of the spar preform is easier, but additional bonding steps and materials are required
Solution Approach 1:
The polymerization process is merged into two stages: partial polymerization during spar preform fabrication, and complete polymerization after assembly. This merging eliminates the need for separate bonding steps and additional bonding materials, as the resin itself provides the bonding function when fully polymerized, thereby reducing process complexity while maintaining ease of handling.
3Strength
If the first resin is fully polymerized, then the spar preform has maximum stiffness, but the risk of non-conforming bonding and scrapping increases
Solution Approach 1:
Partial polymerization is performed as a preliminary action before assembly, providing sufficient stiffness for handling while maintaining the resin in a reactive state that ensures conforming bonding with the second resin. This preliminary partial polymerization reduces the risk of bonding non-conformities and part scrapping by ensuring proper chemical bonding between the spar and blade preform.
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 improves the mechanical strength of the interface between the spar and the blade body, reduces the risk of deformation and bonding failures, and eliminates the need for additional adhesives, thereby simplifying the manufacturing process and reducing costs.
Implementation Method 1
a partial polymerization step, at which polymerization of the first resin in the spar preform is conducted until partial vitrification of the first resin
Implementation Method 2
a complete polymerization step, at which final polymerization of the first resin and second resin is performed
Data Source
AI summary
A method including the preparation of a spar preform arranged in a first mould, the spar preform including a core and a root; a first injection step of a first thermosetting resin in the spar preform; partial polymerization of the first resin in the spar preform until partial vitrification of the first thermosetting resin; positioning a body preform around the core of the spar preform; injection of a second resin into the blade body preform; and complete polymerization of the first and second resin.