Z-Pin Delamination Detection in Composite Components
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Solution Overview
Problem
Current methods cannot effectively detect and assess the extent or location of delamination in composite components, such as those used in gas turbine engines, which is a critical failure mechanism that can occur due to foreign object impacts like bird strikes, despite through-thickness reinforcement with z-pins.
Innovation Solution
A method and system that measure and compare the material properties of z-pins, including electrical and thermoelectric properties, to estimate delamination by comparing detected properties to reference values, allowing for the estimation of delamination extent and location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If z-pins are used to reinforce composite components through the thickness, then the resistance to delamination and crack propagation is improved, but the ability to detect and locate delamination is worsened due to lack of effective detection methods
Solution Approach 1:
The z-pins serve dual functions: they provide mechanical reinforcement to prevent delamination and simultaneously act as sensors to detect delamination. The material properties of the z-pins change in response to delamination, enabling self-detection without requiring separate sensing components.
Solution Approach 2:
The z-pins are designed to perform multiple functions within a single component: structural reinforcement through crack bridging and damage detection through property monitoring. This multi-functionality resolves the contradiction by making the reinforcement element itself capable of detection.
2Measurement precision
If material properties of z-pins are measured to detect delamination, then the measurement precision of delamination is improved, but the device complexity increases due to measurement and comparison systems
Solution Approach 1:
The patent replaces complex mechanical or optical inspection systems with electrical or thermoelectric property measurements of the z-pins. This substitution simplifies the overall system by using readily measurable electrical properties instead of requiring sophisticated external detection equipment.
Solution Approach 2:
The invention monitors changes in material properties (electrical resistance, thermoelectric properties) of the z-pins to detect delamination. By focusing on specific measurable parameters that change with damage, the system achieves high measurement precision without requiring complex multi-parameter analysis systems.
3Strength
If z-pins extend through the thickness of composite plies, then the strength and stability of the composite component is improved, but the difficulty of manufacturing increases
Solution Approach 1:
The z-pins are pre-formed and positioned before the composite plies are stacked and cured. This preliminary preparation allows for precise placement and integration of the pins into the laminate structure, reducing manufacturing complexity during the assembly process.
Solution Approach 2:
The invention uses composite z-pins made from carbon fiber tow impregnated with thermoset resin, matching the material composition of the surrounding plies. This material compatibility simplifies integration and curing processes, as the z-pins can be co-cured with the plies in a single manufacturing step.
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
Enables the detection and localization of delamination in composite components, informing when repair or replacement is necessary, thereby enhancing the safety and reliability of gas turbine engines.
Implementation Method 1
The material properties detected may be electrical properties. For example, resistance, potential, current, charge and/or capacity may be measured.
Implementation Method 2
the material properties detected may include thermoelectric properties
Implementation Method 3
the material properties detected may include thermoelectric properties or ultrasonic properties
Data Source
AI summary
A method of detecting delamination of a composite component, the composite component having a plurality of plies and a plurality of z-pins extending through the composite component in a direction transverse to the plies. The method includes measuring one or more material properties of one or more of the z-pins. The measured material properties are compared to reference material properties. An estimation of whether delamination has occurred is performed based upon the comparison of the measured material properties and the reference material properties.