Elastomeric Mandrel with Hollow Micro-Particles for Composite Curing
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Solution Overview
Problem
Existing mandrels used in curing composite parts often fail to provide uniform pressure, leading to variations in thickness and difficulty in handling and removal, especially when they are solid or vented, which can result in non-uniform expansion and bulging of composite materials.
Innovation Solution
A mandrel made from an elastomeric material with uniformly distributed hollow micro-particles that deform in response to temperature or pressure changes, creating voids within the mandrel body, allowing for even pressure distribution and easy extraction after curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If solid mandrels are used to maintain structural integrity, then strength is improved, but uniform pressure distribution during curing deteriorates
Solution Approach 1:
The mandrel incorporates a porous internal structure with interconnected voids throughout its body, allowing it to deform uniformly under curing pressure while maintaining external structural integrity. The porous structure enables pressure distribution through the mandrel body without requiring solid construction.
Solution Approach 2:
The mandrel is constructed as a composite structure combining an elastomeric matrix material with embedded hollow micro-particles or porous regions. This composite design provides both the flexibility needed for uniform pressure distribution and the structural integrity required for mandrel function.
2Weight of moving object
If vented bladders are used to reduce weight, then weight is reduced, but reliability deteriorates due to leakage
Solution Approach 1:
The mandrel employs a porous solid structure instead of sealed vented bladders, eliminating leakage risks while maintaining lightweight characteristics. The porous network provides internal volume for pressure equalization without requiring enclosed cavities.
Solution Approach 2:
The mandrel is designed as a single-use disposable component made from inexpensive elastomeric material, eliminating the need for complex, reusable vented bladder systems. After one use, the mandrel is discarded rather than cleaned and reused.
3Manufacturing precision
If complex tooling is used to conform to part contours, then shape accuracy is improved, but device complexity increases
Solution Approach 1:
The mandrel is constructed from flexible elastomeric material that can conform to complex part contours through elastic deformation. This flexibility eliminates the need for complex rigid tooling with multiple adjustable components to achieve contour conformance.
Solution Approach 2:
The mandrel utilizes changes in material properties (elasticity, compressibility) and physical state (deformation under pressure) to adapt to different part geometries. By changing the mandrel's physical parameters during use, simple geometry achieves complex functionality.
4Ease of operation
If mandrels are designed for easy removal, then ease of operation is improved, but manufacturing precision deteriorates due to clearance requirements
Solution Approach 1:
The mandrel is designed as a single-use disposable component that can be easily removed or discarded after one curing cycle. This eliminates the need for complex extraction mechanisms while maintaining high surface finish quality during the single use.
Solution Approach 2:
The mandrel utilizes phase change or significant property change after use (such as thermal expansion during curing followed by contraction, or material degradation) to facilitate easy removal. The mandrel's physical state changes enable extraction without special equipment.
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 mandrel ensures consistent pressure application during curing, reduces the risk of bulging, and facilitates easier handling and removal by expanding and contracting in a controlled manner, resulting in high-quality composite parts with improved surface finishes and reduced manufacturing costs.
Implementation Method 1
the hollow micro-particles deform in response to a change in a processing environment resulting in a distribution of voids in the solid mandrel body
Implementation Method 2
The hollow micro-particles deform based on one or more of (i) a threshold temperature and (ii) a threshold pressure applied to the solid mandrel body resulting in a distribution of voids in the solid mandrel body
Implementation Method 3
a solid mandrel body comprising an elastomeric material
Data Source
AI summary
A mandrel for processing a part is described that includes a solid mandrel body with an elastomeric material, and hollow micro-particles embedded within the solid mandrel body in a uniform distribution. The hollow micro-particles deform in response to a change in a processing environment resulting in a distribution of voids in the solid mandrel body. A method for fabricating a composite part is also described that includes placing a base composite layer into a cavity of a tooling surface, inserting the mandrel into the cavity, applying a skin to the mandrel and the base composite layer forming a package, enclosing the package in a vacuum bag and curing the base composite layer and the skin such that during curing the hollow micro-particles deform resulting in the distribution of voids in the solid mandrel body, and removing the mandrel from the cavity of the tooling surface following the curing.