Fiber-End Fixation in Pressure Vessels
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Solution Overview
Problem
Current fiber-reinforced pressure vessels have weak points in compressive strength due to the fiber end, which can detach during vessel expansion and lead to bursting before reaching the bursting pressure.
Innovation Solution
The pressure vessel design secures the fiber end by guiding it out to an area with negligible elongation, such as a valve connection or spigot, and fixing it there using multiple wraps of the fiber composite material or an external fastening means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fiber end is left loose or secured with tape after winding, then the manufacturing process is simple and fast, but the compressive strength is reduced and the fiber end detaches during vessel expansion
Solution Approach 1:
The fiber end is extracted from the central cylindrical area and guided to a peripheral region (pole cap area) where it can be secured without affecting the main structural integrity. This separates the problematic fiber end location from the critical load-bearing area, allowing simple securing methods to work effectively without compromising compressive strength.
Solution Approach 2:
The fiber end is redirected from the radial/circumferential dimension (where it causes weakness) to the axial dimension at the pole cap region. By guiding the fiber end along the vessel axis to the pole cap area, the solution transforms a two-dimensional surface problem into a three-dimensional spatial solution, utilizing the pole cap as a dedicated securing zone.
2Ease of manufacture
If the fiber end is secured within the fiber composite by inserting a loop, then tape fixation is eliminated, but the fiber end still slips out after a certain distance and creates a weak point
Solution Approach 1:
The pole cap region serves as an intermediary structure between the fiber end and the main vessel body. Instead of directly securing the fiber end within the composite layers (which causes slipping), the pole cap acts as a mediator that provides a stable anchoring point, distributing the fiber end forces over a larger area and preventing slip-out.
Solution Approach 2:
The fiber end is guided to the pole cap region before the vessel undergoes pressure loading or further manufacturing steps. This preliminary positioning and securing of the fiber end at the pole cap prevents subsequent detachment during vessel expansion or operation, addressing the reliability issue proactively.
3Device complexity
If the fiber end is placed on the center section of the vessel, then the winding process is simple, but the fiber end detaches during vessel expansion before bursting pressure is reached
Solution Approach 1:
The fiber end is extracted from the center section (cylindrical area) where vessel expansion occurs, and relocated to the pole cap region. This removal of the fiber end from the expansion-prone area eliminates the detachment problem while maintaining winding process simplicity, as the fiber naturally extends to the pole cap during the winding operation.
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
The invention relates to a fiber-reinforced pressure vessel (1) with a securely fixed fiber end (FE) and to a corresponding method (100). The pressure vessel (1) comprises an inner vessel (2) with a cylindrical central section (21) having a cylindrical axis (ZA) and two end caps (22) terminating the cylindrical central section (21), and an outer layer (3) made of fiber composite material (FVM) wound onto the inner vessel (2) for its reinforcement. The outer layer consists of several superimposed layers (L1, L2, L3) of fibers (F) embedded in a matrix material, wherein the fiber (F) from the last wound layer (L3) extends from the central section (21) to a region (33) of the pressure vessel (1) which, under pressure, exhibits at most a negligible elongation relative to the central section (21), and a final section (FL) of the fiber (F) is fixed in this region at least with one fiber end (FE).