Mandrel Structure with Fitting Recesses for Filament Winding
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Solution Overview
Problem
In the filament winding process for forming fiber reinforced resin vessels, existing mandrel structures fail to securely fix fittings, leading to disturbances in the surrounding reinforcing fibers and potential flaws in the completed pressure vessel.
Innovation Solution
A mandrel structure with a hollow shell made of a water-soluble material, featuring receiving recesses for rotationally fast engagement of fittings, and a shaft with positioning nuts to securely clamp the mandrel and fittings, ensuring accurate and reliable positioning of fittings relative to the mandrel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional mandrel structures are used without receiving recesses, then the structure is simpler, but the fittings cannot be securely fixed to the mandrel
Solution Approach 1:
The mandrel is divided into functional segments: the main hollow shell and multiple receiving recesses. Each recess is a distinct structural element that independently engages with a fitting, allowing the mandrel to provide secure fixation at multiple locations without requiring a completely redesigned complex structure. This segmentation enables reliable fitting fixation while maintaining reasonable structural simplicity.
Solution Approach 2:
The receiving recesses are pre-formed as integral parts of the mandrel structure before the filament winding process begins. This preliminary formation of engagement features ensures that fittings can be securely mounted in predetermined positions on the mandrel, providing reliable fixation from the outset without requiring additional complex assembly steps or structures during the winding process.
2Manufacturing precision
If fittings are not securely fixed to the mandrel, then the mandrel structure is simpler, but the surrounding reinforcing fibers are disturbed causing vessel flaws
Solution Approach 1:
The mandrel is segmented into a main body and multiple discrete receiving recesses, each positioned to correspond with fitting locations. This segmentation allows the recesses to be strategically placed to provide fiber support exactly where fittings are mounted, preventing fiber disturbance without requiring complex structures across the entire mandrel surface.
Solution Approach 2:
The receiving recesses act as intermediary structures between the fittings and the mandrel body. These recesses provide a mechanical interface that secures the fittings while also serving as fiber support features that prevent reinforcing fibers from being disturbed during the winding process, thus maintaining manufacturing precision.
3Measurement precision
If the mandrel uses a hollow shell structure with receiving recesses, then fitting positioning reliability is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The receiving recesses are formed as integral features of the mandrel hollow shell during the mandrel manufacturing process itself, before the mandrel is used for filament winding. This preliminary formation of precise engagement features ensures accurate fitting positioning is built into the mandrel structure, avoiding the need for post-manufacturing adjustments or complex assembly procedures.
Solution Approach 2:
The receiving recesses are merged with the hollow shell structure of the mandrel, forming an integrated design where the recesses are part of the mandrel's basic geometry. This merging eliminates the need for separate components or additional manufacturing steps, maintaining ease of manufacture while achieving precise fitting positioning through the unified hollow shell structure with built-in recesses.
Data Source
AI summary
A mandrel structure for use in manufacturing a fiber reinforced resin vessel by a filament winding process, includes: a shaft having a pair of axial ends configured to be supported by a drive unit; a mandrel having the shaft passed therethrough; and a pair of fittings having the shaft passed therethrough and projecting axially from respective axial ends of the mandrel. The mandrel is formed as a hollow shell made of a water-soluble material, and includes a pair of shaft holes receiving the shaft therein, and a receiving recess formed in a part of the mandrel surrounding each shaft hole and configured to engage the corresponding fitting in a rotationally fast manner.