Widened Vertical Webs and Horizontal Girders for Oil Tanker Cargo Holds
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Solution Overview
Problem
Conventional cargo hold structures in oil tankers face issues with structural vulnerability due to heavy crossties that are prone to vibrations and sloshing, leading to potential marine safety accidents and increased manufacturing and maintenance costs.
Innovation Solution
A cargo hold structure where vertical webs on longitudinal bulkheads are widened and interconnected by horizontal girders, eliminating the need for crossties to control sloshing and enhance structural strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If crossties are mounted between vertical webs to support longitudinal bulkheads, then structural strength is improved, but weight increases and the structure becomes vulnerable to vibrations and sloshing
Solution Approach 1:
The invention removes the crossties from the cargo hold structure entirely. Instead of using horizontal crossties to connect vertical webs, the patent employs only vertical webs with increased width (0.15H to 0.20H) and strategically positioned stiffeners to provide the necessary structural support, thereby eliminating the harmful elements while maintaining strength
Solution Approach 2:
The invention changes the dimensional parameters of the vertical webs by increasing their width from the conventional 0.1H to 0.15H-0.20H of the cargo hold height. This parameter change allows the vertical webs to bear the loading independently without requiring crossties, thus reducing weight while maintaining structural integrity
2Strength
If crossties are used to interconnect vertical webs, then structural support is provided, but manufacturing cost and maintenance cost increase
Solution Approach 1:
The invention extracts and eliminates the crossties from the structure, reducing the number of components that need to be manufactured, installed, and maintained. This simplification directly reduces manufacturing costs and eliminates ongoing maintenance requirements for crosstie inspection and replacement
Solution Approach 2:
The invention merges the support function previously distributed across multiple components (vertical webs and crossties) into a simplified system using only vertical webs and stiffeners. This consolidation reduces the total number of parts and assembly steps, lowering manufacturing complexity and cost
3Strength
If crossties are suspended in cargo hold space to interconnect vertical webs, then longitudinal bulkheads are supported, but the structure is vulnerable to vibrations and load sloshing
Solution Approach 1:
The invention removes the crossties that are vulnerable to vibrations and sloshing forces. By eliminating these horizontal members that span the cargo hold space, the structure becomes more resistant to dynamic loads from vibrating hulls and sloshing cargo, as there are no long horizontal members to act as vibration amplifiers
Solution Approach 2:
Instead of using horizontal members (crossties) to connect vertical elements, the invention inverts the approach by relying solely on strengthened vertical elements (wider vertical webs with stiffeners) to provide support. This vertical-only configuration is inherently more resistant to horizontal vibrations and sloshing forces
Data Source
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AI summary
A cargo hold structure for an oil tanker is provided, in which a plurality of vertical webs that is mounted on longitudinal bulkheads of the cargo hold in a height direction of a hull is made wide and horizontal girders which connect the vertical webs to each other and support them, thereby controlling the sloshing load of the cargo hold and improving the structural strength of the cargo hold without having to mount crossties. The cargo hold structure includes a longitudinal bulkhead (20) arranged in a lengthwise direction of a hull to divide an internal space, a plurality of vertical webs (22) coupled onto the longitudinal bulkhead (20) in a height direction of the hull, the vertical web (22) having a width of 0.15 to 0.20 times the total height (H) of the cargo hold, and a horizontal girder (24) arranged between the vertical webs (22) in the lengthwise direction of the hull, the level of the horizontal girder (24) being within 30% to 60% of the total height (H) of the cargo hold from the bottom thereof.