UD Composite Surface Treatment for Low Backface Signature Armor
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Solution Overview
Problem
Existing ballistic resistant composites face challenges in achieving both superior V50 ballistic performance and low backface signature, as the interfacial adhesion of polymeric binder materials with fiber surfaces is often hindered by fiber surface finishes, leading to delamination and reduced composite structural properties.
Innovation Solution
The process involves removing at least a portion of the fiber surface finish to expose the fiber surface, allowing direct contact and bonding with polymeric binder materials, thereby enhancing interlaminar lap shear strength and reducing backface signature through improved fiber-fiber bonding and friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fiber surface finish is applied to reduce static build-up and facilitate processing, then ease of manufacture is improved, but interfacial adhesion of polymeric binder materials deteriorates
Solution Approach 1:
The fiber surface finish is removed before applying the polymeric binder material, creating a clean surface that enables strong interfacial adhesion. This preliminary cleaning action prevents the adhesion problem from occurring in the first place, allowing both ease of manufacture and strong bonding to be achieved.
Solution Approach 2:
The fiber surface finish is extracted or removed from the fiber surface before binder application. This extraction eliminates the barrier that would otherwise prevent effective bonding between the polymeric binder and the fiber surface, resolving the contradiction between ease of processing and interfacial adhesion.
2Strength
If polymeric binder material is applied to bind fibers together, then composite structural integrity is improved, but delamination occurs due to insufficient adhesion
Solution Approach 1:
The fiber surface is preliminarily cleaned of finish before binder application, ensuring that the polymeric binder material can achieve maximum adhesion to the fiber surface. This preliminary surface preparation prevents delamination by establishing strong bonding from the outset.
Solution Approach 2:
The surface energy and chemical composition of the fiber surface are changed by removing the finish, transforming it from a low-energy, inert surface to a high-energy, reactive surface that strongly adheres to the polymeric binder material, thereby preventing delamination.
3Ease of operation
If fiber surface finish is present to protect fiber from equipment damage, then ease of operation is improved, but fiber-fiber bond strength deteriorates
Solution Approach 1:
The fiber surface finish is removed before the bonding operation, allowing direct fiber-to-fiber contact and strong bonding. The protection function of the finish is no longer needed at this stage, and its removal enables the critical bonding action to occur effectively.
Solution Approach 2:
The fiber surface finish is extracted from the fiber surface at the appropriate stage in the process, eliminating the barrier to fiber-fiber bonding while the fibers are being consolidated into the composite structure.
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 results in fibrous composites with interlaminar lap shear strength of at least 756 N and a backface signature of less than 8 mm, significantly improving the composite's ability to resist projectile impacts while minimizing blunt trauma injuries.
Implementation Method 1
said polymeric binder material is in direct contact with the fiber surfaces in the areas where the fiber surface is not covered by the fiber surface finish
Data Source
AI summary
Fabrication of ballistic resistant fibrous composites having improved ballistic resistance properties. More particularly, ballistic resistant fibrous composites having high interlaminar lap shear strength between component fiber plies or fiber layers, which correlates to low composite backface signature. The high lap shear strength, low backface signature composites are useful for the production of hard armor articles, including helmet armor.