Composite Specimen Wrinkle Defect Control
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Solution Overview
Problem
The manufacturing of composite components for rotorcrafts faces challenges in managing fiber orientation to prevent wrinkles, which can lead to strength reduction due to out-of-plane fiber deviations, and existing testing methods are costly and inefficient in simulating and characterizing defects like wrinkles, resulting in increased scrap rates and prolonged development times.
Innovation Solution
A method of creating composite specimens with predetermined wrinkle defects by orienting composite materials around a layup tool and using a stretcher to generate specific wrinkle characteristics, allowing for controlled testing and determination of allowable defects, including the use of a stretcher with an actuating mechanism to form closed loops with predetermined wrinkle features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If composite materials are manufactured for rotorcraft components, then weight reduction and improved performance are achieved, but manufacturing challenges lead to defects such as wrinkles, voids, and delamination
Solution Approach 1:
The patent introduces a preliminary action by pre-forming wrinkles in the composite material before final curing. The method involves creating controlled wrinkles in the uncured composite laminate, then curing the material in that wrinkled state to permanently incorporate the defect pattern. This allows researchers to study wrinkle effects without having to manufacture multiple defective parts from scratch.
Solution Approach 2:
The patent employs copying by using a wrinkle template or mandrel to reproduce consistent wrinkle patterns across multiple specimens. The template captures the desired wrinkle geometry and transfers it to the composite material during the pre-forming stage, ensuring repeatable defect characteristics for standardized testing.
2Measurement precision
If existing testing methods are used to simulate and characterize defects, then defect analysis is possible, but the process is costly and inefficient, resulting in increased scrap rates and prolonged development times
Solution Approach 1:
The patent changes the parameter of wrinkle controllability by transitioning from uncontrolled, random wrinkles to precisely controlled wrinkles with specified geometry, depth, and distribution. The method allows adjustment of wrinkle parameters such as amplitude, wavelength, and orientation to match specific defect scenarios of interest.
Solution Approach 2:
The patent segments the testing process into distinct stages: (1) creating the wrinkle pattern in uncured material, (2) curing the material with wrinkles locked in place, and (3) performing standardized tests on the defective specimens. This segmentation allows for efficient batch production of defective test samples.
3Reliability
If full-scale parts with defects are tested, then real production defects can be evaluated, but the process is costly and defect location and severity cannot be fully controlled
Solution Approach 1:
The patent introduces an intermediary approach by using subscale parts with controlled wrinkle inclusions rather than full-scale defective parts. The wrinkle patterns are incorporated into smaller test specimens that replicate the essential defect characteristics while being more economical to manufacture and test.
Solution Approach 2:
The patent applies local quality by concentrating wrinkle defects in specific localized regions of the composite material rather than distributing them uniformly or requiring entire full-scale components to be defective. This allows focused testing on critical defect locations.
Data Source
AI summary
In an aspect, there is a method of determining allowable defects for a composite component comprising identifying at least one wrinkle characteristic of a composite component wrinkle defect; making a first plurality of specimens each having a predetermined wrinkle defect representative of the composite component wrinkle defect; measuring each of the predetermined wrinkle defects in the first plurality of specimens for at least one performance metric to generate performance data; and generating an allowable wrinkle defect profile based on the performance data from the first plurality of specimens. In other aspects, there are methods of making a specimen with a predetermined wrinkle defect.