Ultrasonic Needle Insertion for CMC Preform Pore Expansion
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Solution Overview
Problem
The manufacturing of ceramic matrix composites (CMCs) faces challenges in matrix material infiltration due to narrowing pores in preform fiber tows, making it difficult to achieve proper densification and maintaining structural integrity during the manufacturing process.
Innovation Solution
The method involves using an ultrasonic needle insertion technique where a tool oscillating at an ultrasonic frequency greater than 20 kHz is aligned with the preform to displace fiber tows laterally within a ply, using multi-tip or single-tip tools with tapered and distal portions to facilitate uniform vibration and minimize breakage or fraying of fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If conventional insertion methods are used to create pores in preform, then pore formation is achieved, but pores become narrow and infiltration of matrix material becomes difficult
Solution Approach 1:
The patent employs ultrasonic vibration of a needle tool at frequencies greater than 20 kHz to insert and displace fiber tows, creating pores with controlled dimensions. The vibrational motion enables precise control over pore formation, preventing excessive narrowing while maintaining structural integrity during the insertion process.
Solution Approach 2:
The patent changes the physical parameters of the insertion process by using ultrasonic frequency vibrations and controlling the amplitude and duration of needle insertion. These parameter modifications enable the creation of pores with optimal dimensions for matrix material infiltration, preventing the pores from becoming too narrow.
2Productivity
If needle insertion is performed to expand pores, then infiltration capability is improved, but fiber breakage or fraying may occur
Solution Approach 1:
The ultrasonic vibration of the needle tool reduces friction and mechanical stress on fibers during insertion. The vibrational motion allows the needle to glide through the fiber tows with minimal resistance, expanding pores without causing fiber breakage or fraying, thus maintaining both infiltration capability and fiber integrity.
Solution Approach 2:
The patent applies ultrasonic vibration as a cushioning mechanism that prevents direct mechanical damage to fibers during needle insertion. The vibrational energy acts as a protective buffer, allowing the needle to expand pores while minimizing stress concentration points that could lead to fiber breakage.
3Ease of manufacture
If traditional densification processes are used, then CMC manufacturing is achieved, but structural integrity is compromised during the process
Solution Approach 1:
The patent performs preliminary pore expansion using ultrasonic needle insertion before the densification process. This preliminary action creates optimally sized pores that facilitate subsequent matrix material infiltration while maintaining preform structural integrity, avoiding the need for aggressive densification methods that could compromise strength.
Solution Approach 2:
The ultrasonic vibration technique provides a gentle yet effective method for pore expansion that preserves fiber alignment and preform structure. This vibrational approach enables controlled pore formation without the mechanical trauma associated with traditional densification methods, maintaining structural integrity throughout the manufacturing process.
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 approach effectively expands the preform pores, improving the infiltration of matrix material and reducing the likelihood of fiber breakage or fraying, thereby enhancing the structural characteristics and densification of CMCs.
Implementation Method 1
oscillating the tool along a longitudinal direction of the tool at an ultrasonic frequency greater than twenty kilohertz
Data Source
AI summary
A method of displacing tows of a preform prior to densification includes aligning a multi-tip tool with the preform and oscillating the multi-tip tool in contact with tows of the preform. A plurality of tips of the tool contact the tows of preform during operation and thereby displace tows laterally within a ply.