Type IV Cylinder-Frame Flexible Connection for Boss Interface Stress Relief
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Solution Overview
Problem
The rigid connection structure of Type IV hydrogen cylinders with container frames leads to stress concentration and potential failure at the interface of metal and non-metallic materials, increasing the risk of accidents such as leakage and explosion due to deformation and rotation during hydrogen storage and transport.
Innovation Solution
A flexible connection device with a damping block, anti-rotation block, bushing, upper and lower clamping blocks, and adjusting gaskets that allow axial movement and consume energy through damping composite materials to reduce torque and stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid connection structure is used to fix the Type IV cylinder on the container frame, then the cylinder is completely restricted from moving axially or rotating circumferentially, but the interface of the boss (metal) and the composite overwrap/plastic liner (nonmetal) experiences stress concentration and deformation under complex working conditions
Solution Approach 1:
The connection structure transitions from a completely rigid static connection to a dynamic flexible connection that allows controlled axial movement and circumferential rotation. The flexible connection plate can deform elastically to accommodate cylinder expansion/contraction and rotational movement, preventing stress concentration at the boss interface while maintaining overall stability.
Solution Approach 2:
The connection structure changes its mechanical parameters (rigidity, movement range) to adapt to different working conditions. The flexible connection plate's deformation capacity allows the system to adjust between rigid stability and flexible stress relief based on operational requirements.
2Stability of the object's composition
If the Type IV cylinder is rigidly fixed on the support plate, then axial movement is completely restricted, but the binding force during expansion/contraction increases stress on the interface
Solution Approach 1:
The flexible connection plate acts as a thin flexible element that can deform to accommodate thermal expansion and contraction of the Type IV cylinder. This flexibility releases binding forces during expansion/contraction cycles while maintaining axial position stability through elastic deformation rather than rigid constraint.
Solution Approach 2:
The flexible connection plate serves as a pre-designed cushioning element that anticipates and absorbs the binding forces generated during thermal expansion and contraction. By allowing controlled deformation beforehand, it prevents stress concentration before it occurs at the boss interface.
3Stability of the object's composition
If the Type IV cylinder is completely fixed against circumferential rotation, then position stability is improved, but the damping block cannot be squeezed to consume energy during rotation
Solution Approach 1:
The circumferential rotation, which could be considered a harmful unstable movement, is converted into a beneficial energy dissipation mechanism. By allowing controlled rotation and squeezing the damping block, the system transforms potentially harmful rotational movements into useful energy consumption that reduces torque on the boss interface.
Solution Approach 2:
The damping block serves as an intermediary element between the cylinder and the fixed support structure. It mediates the circumferential rotation by providing energy dissipation through deformation, allowing controlled rotational movement while ultimately transferring stabilized forces to the support plate.
4Ease of manufacture
If rigid connection is used for Type I, II and III cylinders, then the structure is simple and reliable for metal materials, but it does not account for the characteristics of Type IV cylinder interface between metal and non-metallic materials
Solution Approach 1:
The connection structure applies different mechanical properties to different parts: the flexible connection plate provides flexibility and deformation capacity at the interface with the Type IV cylinder's composite overwrap, while the support plate and fastening bolts maintain rigid structural support. This local differentiation of mechanical properties matches the heterogeneous nature of the Type IV cylinder construction.
Solution Approach 2:
The connection system effectively creates a composite connection structure combining rigid metal components (support plate, bolts) with a flexible element (connection plate) that can accommodate the interface between metal boss and non-metallic composite overwrap. This composite approach mirrors the Type IV cylinder's own composite construction philosophy.
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 flexible connection device reduces the risk of damage and failure by allowing axial movement and energy consumption, improving stress distribution and safety of hydrogen storage containers.
Implementation Method 1
the damping block is squeezed by the circumferential rotation of the cylinder to consume energy
Implementation Method 2
energy consumption through damping composite materials
Implementation Method 3
allowing axial movement and energy consumption, improving stress distribution
Data Source
AI summary
A flexible connection device of a Type IV cylinder and a container frame, comprising a damping block, an anti-rotation block, a bushing, upper and lower clamping blocks (43, 44), and the like. The damping block cooperates with the anti-rotation block to flexibly control the circumferential rotation of the Type IV cylinder; and the bushing is combined with the upper and lower clamping blocks (43, 44) to limit the axial motion of the Type IV cylinder. For the feature that the interface of a boss and a plastic liner/composite overwrap is prone to premature failure, by allowing axial movement of one end of the Type IV cylinder in the container within a small range, a binding force borne by the cylinder during expansion/contraction is released, and the damping block is squeezed to consume energy.