Multidirectional Filament Reinforced Tape for Pultrusion
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Solution Overview
Problem
Current prepreg tapes used in pultrusion processes are inefficient due to labor-intensive manufacturing methods, limited filament orientation in transverse directions, and susceptibility to operator errors and shear failures, which result in suboptimal strength and product defects.
Innovation Solution
A three-layer prepreg tape design where the center layer has filaments oriented at 90 degrees to the length direction, sandwiched between two thin layers with 0-degree filaments, fully bonded using the resin, allowing for increased filament ratio and balanced design, eliminating the need for spot welding and reducing shear failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional unidirectional prepreg tape is used with filaments aligned in the length direction, then the composite achieves high strength in the length direction, but the transverse strength is relatively weak and insufficient for applications requiring 90-degree strength
Solution Approach 1:
The tape is segmented into multiple layers with different filament orientations. The center layer has filaments oriented at 90 degrees to the length direction, while outer layers have filaments oriented in the length direction. This segmentation allows each layer to contribute to specific strength requirements, achieving both high transverse and longitudinal strength without requiring complex manual assembly of separate pieces
Solution Approach 2:
The invention transitions from a single-layer unidirectional structure to a multi-layer multidirectional structure. By adding the dimension of layer stacking with different orientations, the tape achieves enhanced properties in multiple directions simultaneously, solving the limitation of conventional unidirectional tapes that are strong only in the filament direction
2Adaptability or versatility
If cross pieces of unidirectional prepreg tape are manually attached to base strips to create multidirectional tape, then transverse filament orientation is achieved, but the process becomes labor intensive and prone to operator errors
Solution Approach 1:
The multidirectional tape structure is pre-manufactured with the center layer containing 90-degree oriented filaments already integrated between outer layers of longitudinal filaments. This preliminary action eliminates the need for manual attachment of cross pieces during production, significantly improving manufacturing efficiency while maintaining filament orientation flexibility
Solution Approach 2:
The invention merges multiple unidirectional layers into a single integrated multidirectional tape structure. The center layer with transverse filaments is combined with outer layers having longitudinal filaments, creating a unified tape that provides both orientation types simultaneously without requiring separate assembly operations
3Ease of manufacture
If spot welding is used to attach cross pieces to base strips, then the two layer tape can be formed, but the spot welds frequently fail and require manual reattachment
Solution Approach 1:
The invention replaces the mechanical spot welding system with a resin-based bonding system. The thermoplastic resin in the center layer bonds the transverse filaments to the outer layers through melting and solidification, eliminating the unreliable spot welding process and providing consistent, reliable attachment without manual reattachment
Solution Approach 2:
The invention changes the bonding mechanism from mechanical (spot welding) to thermal-resin based. By controlling the temperature parameters during processing, the thermoplastic resin melts and bonds the layers together, then solidifies to create a reliable permanent attachment that eliminates the failure modes of spot welding
4Stability of the object's composition
If equal quantities of filaments are placed in longitudinal and transverse directions, then balanced design is achieved, but the composite is inefficient because 50% of filaments in the lengthwise direction are not used to carry bending load across the width
Solution Approach 1:
The invention applies local quality by placing different quantities of filaments in different locations and orientations. The center layer contains a higher concentration of filaments oriented at 90 degrees to carry bending loads across the width, while the outer layers have filaments oriented in the length direction. This localized filament distribution optimizes the use of each filament for its specific loading condition
Solution Approach 2:
The invention introduces asymmetry in the filament distribution, with the center layer having a different filament orientation and quantity compared to the outer layers. This asymmetric structure allows the center layer to specialize in carrying transverse bending loads while the outer layers provide longitudinal strength, eliminating the inefficiency of symmetric unidirectional designs
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 three-layer tape design enhances filament efficiency, increases the strength of the final product, reduces operator errors, and minimizes shear failures by allowing higher filament loading in the transverse direction and improved resin distribution, resulting in a stronger and more reliable composite.
Implementation Method 1
Thermoplastic resins are solid at room temperature, and they soften and ultimately melt at elevated temperatures turning into a very viscous liquid
Implementation Method 2
several layers of tape first pass through a heater to remelt the resin. The soft viscous column of resin and filaments then passes through a die, which forms the final desired shape, fusing the resin from all the layers together
Data Source
AI summary
The apparatus is a laminar shear resistant pre-impregnated resin tape for use in die forming pultrusion processes, with the tape formed by integrating three distinguishable layers, each with integrated parallel reinforcing filaments. The layers are arranged within the tape so that the filaments of adjacent layers are oriented at angles to each other. The tape of the preferred embodiment of the invention is constructed with the filaments of the center layer at 90 degrees to the length of the tape and the filaments of the two outer layers aligned with the length of the tape. The center layer can be more heavily loaded with filaments than conventional tapes, and the outer two layers have less than the amount of filament load of the center layer.