Fibrous Preform Compaction Using Sizing Softening
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Solution Overview
Problem
The existing methods for shaping fibrous structures in composite material manufacturing, such as gas turbine blades, face challenges in maintaining the weave pattern during compaction, often requiring wetting which leads to porosity and mechanical property alterations due to water vapor trapping.
Innovation Solution
A process involving pre-compaction and final compaction steps, where the fibrous structure is heated above the softening temperature of the sizing composition, allowing for flexible shaping without water lubrication, reducing the risk of weave disruption and facilitating easier matrix injection and transformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If water is used to wet the fibrous structure before shaping, then slippage between fibers is facilitated, but water vapor gets trapped during transformation leading to porosity and altered mechanical properties
Solution Approach 1:
The patent changes the physical state of the sizing composition from solid to liquid by heating above its softening temperature, transforming it into a lubricant that facilitates fiber slippage during compaction without introducing water. This parameter change (temperature) enables the sizing to perform the lubrication function previously achieved by water, while avoiding the harmful effects of water vapor entrapment during subsequent transformation steps.
2Stability of the object's composition
If the fibrous structure is compacted without heating, then the sizing maintains its stiffening character, but fiber slippage is hindered making shaping difficult
Solution Approach 1:
The patent applies temperature parameter changes to transition the sizing composition from a stiffening state (below softening temperature) to a lubricating state (above softening temperature) during the shaping process. This temporary parameter change enables fiber slippage and easy shaping, while the cooling step afterward restores the stiffening character to lock in the desired shape and maintain weave stability.
Solution Approach 2:
The process employs periodic temperature variation: heating above the softening temperature during compaction to facilitate shaping, then cooling below the softening temperature afterward to restore stiffness. This periodic thermal action allows the sizing to dynamically switch between lubricating and stiffening functions at appropriate stages of the manufacturing process.
3Ease of operation
If the fibrous structure is wetted with water for compaction, then shaping is facilitated, but manufacturing time increases due to required drying step
Solution Approach 1:
The patent extracts water from the process entirely by using the sizing composition itself as the lubricant. By heating the sizing above its softening temperature, it becomes liquid and provides the necessary lubrication for fiber slippage during compaction. This eliminates the need for water application and subsequent drying steps, directly removing the time-consuming drying operation from the manufacturing process.
4Manufacturing precision
If high compaction pressure is applied directly to the fibrous structure, then final thickness is achieved, but weave disruption occurs
Solution Approach 1:
The patent changes the temperature parameter to above the softening temperature of the sizing composition before applying compaction pressure. This parameter change temporarily reduces the stiffness of the fibrous structure, allowing it to deform under pressure without disrupting the weave pattern. The heating creates a more compliant state that accommodates the necessary deformation while preserving structural integrity.
Solution Approach 2:
The patent applies heating beforehand to create a cushioning effect that protects the weave structure from damage during compaction. The thermal energy softens the sizing, acting as a cushion that allows gradual deformation and fiber rearrangement without sudden stress concentrations that would disrupt the weave. This prior thermal preparation prevents weave disruption during the subsequent mechanical compaction.
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 process enhances the control over deformation, minimizes weave disruption, and eliminates the need for water, thereby reducing manufacturing time and preventing porosity, resulting in improved mechanical properties of the composite material.
Implementation Method 1
the fibrous structure is at a temperature greater than or equal to the softening temperature of the sizing composition
Implementation Method 2
the process further comprises the cooling of the fibrous preform obtained after the step of final compaction
Data Source
AI summary
A process for shaping, by compaction, a fibrous structure obtained by three-dimensional or multilayer weaving between a plurality of layers of warp yarns and a plurality of layers of weft yarns. The yarns of each plurality of layers of warp yarns and layers of weft yarns are coated with a sizing composition. The shaping includes a pre-compaction stage followed by a stage of final compaction of the fibrous structure. During pre-compaction and final compaction, the fibrous structure is at a temperature greater than or equal to the softening temperature of the sizing composition. The process further includes the cooling of the fibrous preform obtained after final compaction of the fibrous structure.