Ship Deck Vibration Damping with Flat Leaf Springs
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Solution Overview
Problem
Existing vibration damping devices for ships' bow thrusters are complex, inflexible, and inefficient, as they are designed for specific thrusters and primarily address vibrations at the source rather than effectively reducing propagation to the hull and decks where passengers and crew are located.
Innovation Solution
A vibration damping device featuring a base, actuator, and a mass-spring assembly with flat leaf springs arranged perpendicular to the actuation direction, allowing for adjustable mass and increased rigidity, mounted on a ship's deck with sensors and controllers to actively counteract vibrations perpendicular to the deck.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a mass-spring assembly with helical springs is used to dampen vibrations, then vibration damping capability is improved, but device complexity increases due to need for additional guidance structures
Solution Approach 1:
The patent replaces traditional helical springs with flat flexible plates (leaf springs) that provide the necessary elastic restoring force. These flat plates inherently provide both the spring function and structural stability without requiring additional guidance mechanisms, thus reducing device complexity while maintaining vibration damping capability.
2Object-affected harmful factors
If the moving mass is increased to counteract vibration amplitude, then vibration damping capability is improved, but weight of the device increases
Solution Approach 1:
The patent changes the configuration parameters of the flat plate springs (number of plates, dimensions, thickness) to optimize the stiffness and damping characteristics. By adjusting these parameters, the system achieves effective vibration damping with a reduced moving mass compared to traditional helical spring systems.
3Object-affected harmful factors
If the vibration damping device is installed at the vibration source, then vibration damping capability is improved, but adaptability to different ship configurations decreases
Solution Approach 1:
The patent designs a universal vibration damping device that can be installed in multiple locations on the ship (at the vibration source or at the deck level). The device's flat plate spring configuration and adjustable mass allow it to adapt to different ship types, thruster configurations, and installation locations, providing versatile vibration damping solutions.
4Reliability
If traditional helical springs are used with displacement limited to prevent fatigue, then reliability is improved, but vibration damping capability decreases requiring increased moving mass
Solution Approach 1:
The patent uses flat plate springs that can be designed with appropriate thickness and dimensions to achieve the required displacement without exceeding material fatigue limits. The flat plate configuration allows for optimized stress distribution and can accommodate larger displacements safely, thereby maintaining both reliability and vibration damping capability.
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 provides a simpler, adaptable, and effective means to dampen vibrations at the deck level, reducing harmful propagation and enhancing passenger comfort by actively addressing vertical vibration components, which were previously overlooked.
Implementation Method 1
a spring part of which a first end is mounted on the moving mass and a second end of which is mounted on the base, characterized in that the spring part comprises at least a first set of at least two flat leaf springs
Implementation Method 2
at least one actuator; a mass-spring assembly comprising a moving mass mounted on the actuator so that said moving mass can be moved by the actuator
Data Source
Figure 1
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AI summary
The invention provides a vibration damping device (100), in particular intended to dampen vibrations generated by a bow thruster of a ship, the device comprising: - a base (101) intended to be fixed to a structure for which it is desired to dampen the vibrations; - an actuator (102) with an actuation direction; - a mass-spring assembly comprising a moving mass (103) mounted on the actuator and a spring part (1041, 1042, 1043, 1044) mounted between the moving mass and the base, characterized in that the spring part comprises two flat-leaf springs (1041, 1042) arranged in parallel along a main extension direction (DEP) substantially perpendicular to the actuation direction and located between the base and the moving mass with reference to the actuation direction. The invention also relates to a ship provided with such a device and an associated method.