Polyurea Coating for Aircraft Landing Gear Impact Resistance
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Solution Overview
Problem
Aircraft landing gear coatings face damage from foreign object debris due to their unique ability to operate on short, austere runways, requiring a coating system with high tensile strength and durability to withstand projectile impacts.
Innovation Solution
A polyurea coating system with a steel substrate, formulated from specific A and B components including polyisocyanate, polyether polyol, diamines, and UV stabilizers, providing a tensile strength of over 3500 psi and 700% elongation, which is applied via spraying to protect aircraft landing gear from impact damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polyurethane coatings are used on landing gear, then the coating system provides basic protection, but it suffers from insufficient impact resistance and durability against foreign object debris
Solution Approach 1:
The patent changes the chemical composition parameters of the coating system by using polyurea instead of polyurethane, specifically incorporating aromatic diamines and polyether polyamines in controlled ratios to achieve superior mechanical properties including 3000-5000 psi tensile strength and over 100% elongation, which directly resolves the insufficient impact resistance problem
Solution Approach 2:
The patent creates a composite coating system by combining multiple components (polyisocyanate, aromatic diamine, polyether polyol, polyether polyamine) in specific proportions, forming a multi-component polyurea system that achieves enhanced durability and impact resistance against foreign object debris compared to single-component polyurethane coatings
2Strength
If the coating formulation includes multiple components (A-side and B-side), then the tensile strength and elongation are improved, but the coating system complexity increases
Solution Approach 1:
The patent divides the coating system into two separate components (A-side containing polyisocyanate and polyether polyol, B-side containing aromatic diamine and polyether polyamine), allowing each component to be optimized independently while maintaining overall system performance of over 3500 psi tensile strength and 700% elongation
Solution Approach 2:
The patent designs the multi-component polyurea system to serve multiple functions simultaneously: providing structural strength, elongation capability, adhesion to substrates, and resistance to environmental degradation, thereby justifying the increased formulation complexity through enhanced overall performance
3Stability of the object's composition
If the coating is designed for high elongation (700% or more), then the impact resistance is improved, but the adhesion to steel substrate may be compromised
Solution Approach 1:
The patent optimizes different regions of the coating system for different properties: the B-side components (aromatic diamine and polyether polyamine) are specifically formulated to provide high elongation (700% or more) for impact absorption, while the A-side components and their interaction with the substrate are optimized to ensure strong adhesion to steel surfaces, allowing each region to excel at its primary function
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 polyurea coating system offers superior impact resistance, durability, and adhesion to steel, outperforming existing polyurethane coatings by providing improved protection against projectile impacts and environmental factors like sand and rain erosion.
Implementation Method 1
a polyisocyanate, from about 25 to about 70 percent, preferably from about 30 to about 65 percent; polyether polyol, from about 10 to about 75 percent, preferably from about 15 to about 70 percent
Implementation Method 2
a silane coupling agent, an optionally pigment, an optional UV stabilizer
Data Source
AI summary
A process for coating a metallic surface of an aircraft. The process includes applying to the metallic surface a composition that polymerizes to form a polyurea having a tensile strength of more than 3500 psi and at least 700% elongation. The polyurea can be formed from an A-side and a B-side, where the weight percents of components for the A-side are: from about 30 to about 65 percent of polyisocyanate; from about 15 to about 70 percent of a polytetramethylene ether glycol; diluent, from 0 to about 20 percent; where the weight percents of components for the B-side are: from 35 to about 40 percent of one or more aromatic diamines; from about 20 to about 70 percent of one or more amine terminated polyether polyols.