LNG Membrane Reinforcement Member for Corrugation Collapse Prevention
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Solution Overview
Problem
Conventional LNG cargo tank membranes with corrugations are prone to collapse under increased hydrostatic or dynamic pressure, and existing reinforcement methods either decrease flexibility or fail to properly expand and contract, leading to stress issues in weld zones.
Innovation Solution
A reinforcing member is placed inside the corrugations of the membrane, made of nonflammable foam or wooden materials, with a shape matching the corrugation, providing additional rigidity without increasing facial rigidity and including features like reinforcing pipes and paths for leak testing, to prevent deformation and enhance insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of the membrane is increased to reinforce the rigidity of the corrugations, then the strength and pressure resistance are improved, but the flexibility decreases
Solution Approach 1:
A reinforcing member is inserted inside the corrugation of the membrane, creating a nested structure where the reinforcing member is contained within the corrugation space. This allows the reinforcing member to provide structural support and prevent collapse under pressure while the membrane itself maintains its original thickness and flexibility for thermal expansion and contraction.
2Strength
If reinforcing ridges are formed on the corrugations to increase facial rigidity, then the collapse resistance is improved, but the ability to expand and contract properly is reduced, leading to increased stress in weld zones
Solution Approach 1:
The reinforcing member is placed inside the corrugation rather than adding external ridges to the surface. This internal reinforcement provides collapse resistance through structural support from within, while allowing the external corrugation geometry to remain unchanged and functional for thermal movement.
Solution Approach 2:
The reinforcing member is selectively placed only in regions where collapse resistance is needed, rather than uniformly increasing rigidity across the entire membrane. This localized reinforcement maintains the ability of the membrane to expand and contract in non-critical areas, reducing stress concentration in weld zones.
3Strength
If reinforcing members are placed inside the corrugations to prevent collapse, then the pressure resistance is improved, but the device complexity increases
Solution Approach 1:
The reinforcing member utilizes the existing corrugation space, nesting within the already-formed structural geometry. This approach adds reinforcement functionality without requiring additional external structures or complex assembly procedures, as the reinforcing member simply inserts into the pre-existing corrugation voids.
Data Source
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AI summary
The present invention is related to a reinforcing member for a membrane for improving the pressure-withstanding property of the membrane having corrugations, and a membrane assembly having the reinforcing member and a method of constructing the membrane assembly. By providing a reinforcing member for a membrane having corrugations and installed in an insulating structural member of an LNG cargo, the present invention can prevent the collapse of the corrugation and attenuate shocks against a same load without increasing the facial rigidity of the corrugation, and improve the insulating property by forming an additional insulating layer.