Pneumatic Fender Cord Angle Segmentation for Smooth Expansion
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Solution Overview
Problem
Pneumatic fenders face resistance issues when expanding under specified internal pressure due to shear forces acting on intermediate rubber layers, hindering smooth expansion and maintaining a predetermined shape.
Innovation Solution
The pneumatic fender design features reinforcing layers with cords extending in parallel and intersecting directions, with a cord angle between 25° and 45°, reducing shear force on intermediate rubber layers and allowing smooth expansion by distributing resistance only between sets of layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the cord angle of reinforcing layers is set to 15° to 45° to enable greater expansion, then the body expands more when loaded with internal pressure, but shear force acts on intermediate rubber layers causing large resistance that hinders smooth expansion
Solution Approach 1:
The reinforcing layers are segmented into sets where adjacent layers within each set have cords extending in identical directions, while sets themselves are arranged with intersecting cord directions. This segmentation allows shear force to act only between sets rather than across all intermediate rubber layers, significantly reducing resistance during expansion while maintaining structural integrity
Solution Approach 2:
Different regions of the reinforcing structure are assigned different cord directions locally. Within each set, cords extend in identical directions to minimize local shear force, while adjacent sets have intersecting directions to maintain overall structural strength. This local differentiation optimizes both expansion smoothness and structural integrity
2Stability of the object's composition
If the cord angle is set to approximately the angle of repose (54° to 55°) to maintain stable shape, then the body size does not change much when filled with air, but the expansion capability is limited
Solution Approach 1:
The cord angle is designed to dynamically change during expansion from the initial 25°-45° range toward the angle of repose (54°-55°). This dynamic adjustment allows the structure to transition smoothly from an expanded state to a stable maintained state, achieving both expansion capability and shape stability without contradiction
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 design ensures smooth expansion and maintains a predetermined shape by minimizing shear force on intermediate rubber layers, reducing resistance and ensuring efficient expansion, while maintaining structural integrity and weight optimization.
Implementation Method 1
When the body is filled with air to be loaded with a specified internal pressure
Implementation Method 2
the cord angle of each reinforcing layer of the body portion increases to a stable angle of repose
Data Source
AI summary
Reinforcing layers each have a cord angle set to 25° or greater and 45° or less when a body is in a neutral state. When the body is loaded with a specified internal pressure, intermediate rubber layers disposed between adjacent sets in which cords of the reinforcing layers extend in an intersecting direction are shear-deformed, the cord angle increases approximately to a stable angle of repose, and the expanded body maintains a predetermined shape. In each of the sets being formed of two reinforcing layers layered adjacently, the cords of the reinforcing layers extend in an identical direction at the predetermined cord angle. Since substantially no shear force acts on the intermediate rubber layers disposed between the reinforcing layers, the resistance when expanding the body decreases. This provides a pneumatic fender that expands more smoothly and ensures a predetermined shape when a body is loaded with a specified internal pressure.