Impregnation Mandrel with Vacuum Liner for Composite Casing
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Solution Overview
Problem
The existing methods for producing composite material gas turbine casings face issues with resin impregnation under vacuum, leading to tension in fibrous textures at the angles of flanges, causing unstickage and mass defects between layers.
Innovation Solution
The use of an impregnation mandrel with compaction bars positioned at the angles of flanges before vacuum application ensures uniform compaction and prevents resin mass defects, along with a vacuum liner applied to the central wall and compaction bars, and resin injection and extraction orifices for controlled resin flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If vacuum is applied during resin impregnation, then resin infiltration into fibrous reinforcement is improved, but tension causes unstickage and mass defects at flange angles
Solution Approach 1:
The mandrel is provided with compaction means (such as compaction bars or rollers) that apply mechanical pressure to the fibrous reinforcement at the flange angles before vacuum is applied. This preliminary compaction ensures the layers are properly adhered and positioned, preventing unstickage and mass defects when vacuum is subsequently applied during resin impregnation
Solution Approach 2:
The compaction means are specifically positioned at the flange angles where the problem of unstickage occurs, rather than applying uniform compaction throughout. This localized approach addresses the specific vulnerability at the angles between flanges and central wall while maintaining proper impregnation quality elsewhere
2Shape
If fibrous reinforcement is wound on mandrel to form casing, then desired profile and thickness are achieved, but tension at flange angles causes unstickage during vacuum setting
Solution Approach 1:
The mandrel includes built-in compaction means that are activated during or immediately after the winding process to pre-compress the fibrous reinforcement at the flange angles. This ensures proper layer adhesion is established before the subsequent vacuum impregnation step, preventing unstickage while maintaining the desired casing profile
Solution Approach 2:
The compaction means are strategically positioned only at the flange angles where the winding process creates vulnerable zones. This localized compaction maintains the overall casing shape and profile while specifically addressing the adhesion problem at the critical angle regions
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 solution ensures uniform compaction and prevents resin defects during vacuum impregnation, maintaining the geometry and integrity of the composite material casing, enhancing the manufacturing process for gas turbine components.
Implementation Method 1
A difference in pressure is then set between the exterior and the space delimited by the mandrel and the liner containing the fibrous reinforcement
Implementation Method 2
means for injecting resin into a space delimited between the vacuum liner and the mandrel at a longitudinal end of the fibrous reinforcement and for extracting it at an opposite end
Data Source
AI summary
An impregnation mandrel for production of a gas turbine casing made from composite material, including: a mandrel having a central wall and two side plates; compaction bars, each including (i) a wedge configured to bear against a fibrous reinforcing part covering angles formed between the central wall and the side plates of the mandrel, and (ii) an attachment flange configured to be attached to the corresponding side plate of the mandrel; a flexible casing forming a vacuum bag and configured to be applied at least against the fibrous reinforcing part covering the central wall of the mandrel; and a mechanism for injecting resin into a space defined between the vacuum bag and the mandrel at one of longitudinal ends of the fibrous reinforcement and for extracting the resin at the opposite end.