Offshore Hull Cylinder Rolling to Reduce Out-of-Roundness
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Solution Overview
Problem
Conventional methods for constructing buoyant columns for offshore structures suffer from low precision due to gravity-induced distortions during the bending and assembly of steel plates, leading to increased out-of-roundness tolerance and compromised product quality.
Innovation Solution
A method involving welding plates to form a plate assembly, passing it through a rolling machine in a vertical orientation to bend into a cylinder, and welding the ends to create a cylindrical external wall, with ring reinforcements added to enhance structural integrity, allowing for the desired bend radius to be imparted in a single rolling step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to bend and assemble steel plates for buoyant columns, then construction can proceed with standard equipment, but gravity-induced distortions cause increased out-of-roundness tolerance and reduced manufacturing precision
Solution Approach 1:
The patent inverts the conventional bending approach by using a vertical rolling machine instead of horizontal bending, and by rolling the plate assembly in a vertical orientation rather than the traditional horizontal method. This inversion eliminates gravity-induced distortions and achieves the desired bend radius in a single rolling step, significantly reducing out-of-roundness tolerance while maintaining ease of manufacture
Solution Approach 2:
The patent changes the orientation parameter from horizontal to vertical during the bending process. By passing the plate assembly through a vertical rolling machine with rollers arranged vertically, the process achieves precise cylindrical formation without gravity-induced distortions, improving manufacturing precision without complicating the construction process
2Productivity
If multiple bending steps are used to achieve the desired cylindrical shape, then flexibility in correcting distortions is increased, but construction time and productivity are reduced
Solution Approach 1:
The patent applies preliminary action by designing the vertical rolling machine and plate assembly configuration to achieve the desired bend radius in a single rolling step. The plate assembly is specifically prepared with dimensions and properties that enable it to be formed into the correct cylindrical shape during the first vertical rolling operation, eliminating the need for subsequent bending or correction steps and thereby maximizing productivity while maintaining high manufacturing precision
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
This approach enhances construction efficiency and reduces out-of-roundness tolerance, improving the final product quality by achieving the desired bend radius in a single rolling step and minimizing post-fabrication corrections.
Implementation Method 1
bending the plate assembly into a cylinder during (b)
Implementation Method 2
welding the free ends of the cylinder together after (c) to form a cylindrical external wall
Data Source
AI summary
A method for constructing a hull of an offshore structure includes (a) welding a plurality of plates together to form a plate assembly. The method also includes (b) passing the plate assembly through a rolling machine with the plate assembly in a vertical orientation. In addition, the method includes (c) bending the plate assembly into a cylinder during (b). The cylinder includes a pair of circumferentially adjacent free ends. Further, the method includes (d) welding the free ends of the cylinder together after (c) to form a cylindrical external wall.