Self-Destructing Flow Body for Ship Rudder Impact Protection
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Solution Overview
Problem
Ship rudders with Costa bulbs are susceptible to damage from impacts or pressures due to the bulb's protrusion, which can transfer forces to the rudder blade, increasing the risk of damage.
Innovation Solution
A rudder blade design featuring a flow body that can self-destruct upon impact or pressure, with predetermined breaking points or lines distributed over its surface, allowing it to absorb and dissipate forces without damaging the rudder blade, and can be integrated into existing rudder blades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a Costa bulb is added to the rudder blade, then favorable flow guidance is achieved, but susceptibility to damage from impact or pressure increases
Solution Approach 1:
The flow body is divided into multiple segments with predetermined breaking points between them. When impact or pressure exceeds a certain threshold, these segments can separate from each other, allowing the flow body to dissipate energy through controlled segmentation rather than transferring all force to the rudder blade.
Solution Approach 2:
The flow body is designed as a sacrificial component with predetermined breaking points that will fail under excessive load. This disposable element protects the more valuable rudder blade by absorbing impact energy through its own controlled destruction, similar to how fuse wires protect electrical circuits.
2Reliability
If the flow body is made robust to prevent damage, then reliability improves, but the ability to absorb impact forces through self-destruction is reduced
Solution Approach 1:
Different regions of the flow body have different structural properties. The outer shell maintains sufficient strength for normal operation and flow guidance, while predetermined breaking points create localized weak regions designed to fail first under excessive load, allowing the structure to progress from local failure to complete disintegration in a controlled manner.
Solution Approach 2:
The flow body is pre-designed with predetermined breaking points that act as energy-absorbing features before impact occurs. These pre-planned failure points ensure that when impact happens, the energy is absorbed through controlled fragmentation rather than unpredictable catastrophic failure, providing consistent protective behavior.
3Shape
If the flow body is integrated into the rudder blade, then flow guidance is optimized, but the flow body cannot be easily replaced after damage
Solution Approach 1:
The flow body is segmented into modular components connected by predetermined breaking points that also serve as separation interfaces. This segmentation allows the flow body to be installed as complete modules and, when damaged, replaced by removing and reattaching these modular segments without requiring complex integration work, combining tight integration benefits with easy replaceability.
Data Source
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AI summary
A rudder blade (15) and a propeller (12) are arranged on a driven propulsion axis. A bulb-shaped or zeppelin shaped designed flow body (20) is arranged as an extension of the propulsion axis in the region of the rudder blade. The flow body (20) is designed to be self-destructive or self-releasing in the event of an increase in the effect of force, blow, impact or pressure. The flow body divides the rudder blade into two areas with identical or non- identical in profile. Flow body is made from a metal, fiber composite materials, a metal-nonmetal mixture or a synthetic material.