Automated Fiber Placement with Pulsed Energy Heating
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Solution Overview
Problem
Automated fiber placement (AFP) technologies face limitations in curving prepreg tows due to their stiffness, which restricts the creation of complex surface contours and orientations of reinforcement fibers, leading to peeling issues when the radius of curvature is tight.
Innovation Solution
An automated fiber-placement system comprising a dispenser, compactor, steering mechanism, and energy source, which delivers pulsed energy to fiber-reinforced tape strips to heat and transform them into discrete regions, allowing for precise placement along virtual curvilinear paths without peeling, enabling tighter curvatures and complex orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If prepreg tows are placed with tight radius of curvature, then complex surface contours can be constructed, but the prepreg tows peel away from the tool
Solution Approach 1:
The prepreg tow is divided into multiple discrete segments or zones along its length. Each segment can be independently heated to different temperatures, allowing the tow to be柔ened in specific regions while maintaining stiffness in others, enabling tight curvature without peeling
Solution Approach 2:
The physical state of the prepreg tow is dynamically changed by applying heat. By controlling temperature parameters along the tow, the material transitions between stiff and柔en states, allowing it to conform to tight radii when heated and maintain structural integrity when cooled
2Strength
If prepreg tows are kept stiff to maintain structural integrity, then tensile strength is preserved, but the tows cannot be curved below large threshold radius
Solution Approach 1:
The stiffness of the prepreg tow is made dynamic rather than static. By applying heat locally and temporarily, the tow transitions from a stiff state (maintaining tensile strength) to a柔en state (allowing tight curvature), then back to stiff state after placement, enabling both strength and curvature requirements to be met
3Ease of manufacture
If traditional AFP methods are used with straight parallel placement, then manufacturing simplicity is maintained, but complex surface contours and fiber orientations cannot be achieved
Solution Approach 1:
Different sections of the prepreg tow are treated with different thermal histories, creating local variations in material properties. This allows certain zones to be shaped for tight curvature while other zones remain straight, enabling complex surface contours while maintaining overall process simplicity
Solution Approach 2:
The heating process is applied periodically and sequentially to different segments of the prepreg tow as it is fed through the system. This periodic thermal treatment enables the tow to progressively conform to complex paths while maintaining manufacturing efficiency
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 system enables the construction of composite structures with complex surface contours and desired fiber orientations, overcoming the limitations of traditional AFP by maintaining adhesion and structural integrity at tight radii.
Implementation Method 1
The energy source is configured to deliver a first quantity of pulsed energy and a second quantity of pulsed energy to the leading side of the compactor for respectively heating, to a first temperature, first discrete portions of at least the one fiber-reinforced tape strip and, to a second temperature, second discrete portions of at least the one fiber-reinforced tape strip
Data Source
AI summary
An automated fiber-placement method comprises delivering a first quantity of pulsed energy to first portions of at least one fiber-reinforced tape strip, and delivering a second quantity of pulsed energy to second portions of at least the one fiber-reinforced tape strip, alternating with the first portions. Each one of the second portions at least partially overlaps two adjacent ones of the first portions such that overlapping regions of the first portions and the second portions have a higher temperature than non-overlapping regions of the first portions and the second portions. The automated fiber-placement method further comprises laying down at least the one fiber-reinforced tape strip against a substrate along a virtual curvilinear path, such that (i) at least the one fiber-reinforced tape strip is centered on the virtual curvilinear path, and (ii) the overlapping regions are transformed into discrete tape-regions, geometrically different from the overlapping regions.