Flexible Membrane Trough for Mandrel Sag Prevention
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Solution Overview
Problem
Existing filament winding systems for forming elongate composite tubulars suffer from mandrel sagging, leading to inconsistencies in the side wall of the composite tubulars, such as wrinkles and uneven filament spacing, which compromise the quality and structural performance of the composite.
Innovation Solution
A filament winding system that includes a flexible membrane trough supporting a rotatable mandrel, allowing it to maintain a substantially straight axis, with composite filaments and polymer matrix being wound around the mandrel to form a composite tubular, and a method of forming a composite tubular by supporting the mandrel with a continuous flexible membrane to prevent sagging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a mandrel is supported only at its ends during filament winding, then the support structure is simple, but the mandrel sags in the mid portion causing inconsistencies in the composite tubular
Solution Approach 1:
The support structure is segmented into multiple sections: end supports at the mandrel ends and intermediate supports along the mandrel length. This segmentation distributes the support function across multiple points, preventing mid-portion sagging while maintaining structural simplicity through modular support elements.
Solution Approach 2:
The support system transitions from one-dimensional end-point support to two-dimensional distributed support by adding intermediate supports along the mandrel length. This dimensional expansion of the support architecture eliminates sagging without significantly increasing overall system complexity.
2Manufacturing precision
If intermediate supports are added to prevent mandrel sagging, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The intermediate supports are designed to be self-adjusting and self-aligning, automatically adapting to the mandrel's position and shape during winding. This self-service capability eliminates the need for complex adjustment mechanisms and precise alignment procedures, maintaining device simplicity while improving precision.
Solution Approach 2:
The intermediate supports use simple, inexpensive, easily replaceable components that can be quickly adjusted or replaced during operation. This approach minimizes the cost and complexity of the support system while achieving the required manufacturing precision through straightforward, maintainable structures.
3Ease of manufacture
If the mandrel sags during winding, then the setup is simpler, but the composite tubular develops wrinkles and uneven filament spacing
Solution Approach 1:
The intermediate supports are positioned and configured in advance to counteract the expected gravitational sagging of the mandrel before winding begins. This preliminary anti-action prevents the development of wrinkles and uneven filament spacing by maintaining mandrel straightness throughout the winding process, ensuring consistent composite quality.
4Productivity
If elongate tubulars are formed with traditional end-supported mandrels, then production is straightforward, but the mid portion sags compromising structural performance
Solution Approach 1:
The support system is segmented into multiple independent support points along the mandrel length, allowing each section to be optimally positioned for preventing sag. This segmented approach maintains continuous production capability while ensuring the mandrel remains straight throughout, preserving the structural performance of the resulting composite tubular.
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 ensures a consistent and straight composite tubular formation, reducing wrinkles and uneven spacing, thereby enhancing the quality and structural integrity of the composite tubulars.
Implementation Method 1
a flexible membrane trough that is supported along lateral sides of the flexible membrane, a rotatable mandrel having opposing ends mounted in the frame and at least a lengthwise portion of the mandrel between the opposing ends supported in the trough
Implementation Method 2
winding composite filaments of fibers impregnated with a polymer matrix around the mandrel
Data Source
AI summary
A method and apparatus for forming an elongate tubular from a composite material. The composite material includes fibers and epoxy resin that are disposed around an elongated mandrel. The fibers are wound around the outer circumference of the mandrel and the epoxy resin may be applied to the fibers, before, during, or after, being wound onto the mandrel. A trough is provided that supports the mandrel between ends of the mandrel. An example trough includes a flexible membrane supported on its lateral ends to resemble a catenary.