Composite Fillet Joint Mold Thermal Insulation
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Solution Overview
Problem
Existing manufacturing processes for composite 'T' and 'L' joints suffer from deformation under high internal pressures, leading to porosity and undesirable residual stresses in the fillet region, which results in poor quality components with increased weight and aerodynamic losses.
Innovation Solution
Thermally insulating the fillet region during the cure process and using geometrically stable inserts to reduce mould deformation, along with bending the legs of the joint and reducing the thickness of the fillet region to control resin flow and residual stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high internal pressure is applied during resin infusion to ensure thorough wetting of the fibre preform, then resin impregnation quality is improved, but mould deformation increases leading to porosity and poor manufacturing precision
Solution Approach 1:
The mould is divided into different thermal zones with selective insulation at the fillet region, allowing different parts of the component to cure at different rates. This segmentation of the curing process prevents uniform deformation while maintaining resin flow quality.
Solution Approach 2:
Thermal insulation is applied specifically to the fillet region rather than uniformly across the entire mould. This local modification creates a controlled temperature gradient that prevents deformation at the critical fillet area while allowing other regions to cure normally.
2Productivity
If the fillet region cures early during the cure process, then manufacturing time is reduced, but tensile residual stresses increase leading to poor component quality
Solution Approach 1:
The cure process is made sequential rather than simultaneous through selective thermal insulation. The fillet region is insulated to delay its curing until after the main component structure has cured, creating a periodic or staged curing sequence that prevents tensile residual stresses.
3Device complexity
If mould deformation is allowed under high pressure, then device complexity is reduced, but resin flow rate decreases and porosity increases
Solution Approach 1:
Instead of making the entire mould complex and rigid, thermal insulation is applied only to the fillet region to prevent local deformation. This localized approach maintains simple overall mould structure while preventing deformation at the critical area where it would most affect resin flow.
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
Significantly reduces tensile residual stresses in the fillet region, improves resin flow patterns, and enhances the quality of the composite components by minimizing porosity and aerodynamic losses.
Implementation Method 1
provides a mould for use in forming a composite component. The mould includes an insert formed from a thermally insulating material... thermally insulating the fillet region during cure, such that the fillet region is substantially the last region of the component to cure
Data Source
AI summary
A mold for a composite component having a fillet joint, the mold including a mold body having a cavity within which the component is formed, and an insert mating with the mold body and including a forming surface against which, in use, the fillet of the component fillet joint is formed. The insert may be thermally insulating and highly rigid. A method of forming a composite component having a fillet joint using a mold, the method including forcing a surface of the fillet region of the component to adopt a non constant radius of curvature while the component is inside the mold during the cure process is also provided. Additionally, a method of forming a composite component having a fillet joint that is defined between first and second legs the method including placing the legs of the component in bending during cure of the component is described.