Resilient Pile Guiding System for Floating Vessel Stability
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Solution Overview
Problem
The installation of piles in a seabed using a floating vessel is challenging due to the vessel's susceptibility to sea state forces, which can cause the pile to pivot and exert large horizontal forces on the vessel, leading to instability and difficulty in maintaining the vessel's position.
Innovation Solution
A pile guiding system with a resilient member that provides a low connection stiffness, allowing relative motions between the pile and the vessel, and a second guiding device that assists in keeping the vessel at the installation location by applying a restoring moment to the pile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid connection is used between the pile guiding system and the floating vessel, then the vessel can provide strong support to the pile, but the vessel becomes heavily loaded by wave-induced forces and loses positioning stability
Solution Approach 1:
The connection between the pile guiding system and the floating vessel is transformed from a rigid static connection to a dynamic resilient connection. The resilient member allows the connection stiffness to adapt to varying wave conditions, providing strong support when needed while absorbing excessive loads during severe sea states, thus maintaining positioning stability.
Solution Approach 2:
The connection stiffness parameter is changed from a fixed high value (rigid connection) to a variable low value (resilient connection). This parameter change allows the system to reduce the natural period of the pile-vessel system, preventing resonance with wave frequencies and reducing the amplification of wave-induced forces on the vessel.
2Stability of the object's composition
If the connection stiffness is high, then the pile is held firmly, but the natural period of pile motion becomes short and may resonate with wave frequencies, increasing loads
Solution Approach 1:
The connection stiffness parameter is reduced to change the natural period of the pile-vessel system. By lowering the stiffness of the resilient member, the natural period is extended beyond the dominant wave period, preventing resonance and the associated amplification of wave-induced forces.
Solution Approach 2:
The resilient member, which initially appears to reduce holding firmness, actually provides a beneficial effect by tuning the system's natural period away from wave frequencies. This converts the potential harm of resonance into a benefit by reducing dynamic amplification of loads.
3Productivity
If a floating vessel is used instead of a jack-up vessel, then installation speed increases and water depth limitations are removed, but the vessel becomes susceptible to sea state forces causing pile instability
Solution Approach 1:
The resilient member acts as an intermediary element between the pile and the floating vessel. It mediates the interaction by providing a compliant connection that reduces the transmission of wave-induced forces from the vessel to the pile, thereby maintaining installation stability despite the vessel's mobility.
Solution Approach 2:
The system transitions from a static rigid connection (jack-up vessel) to a dynamic resilient connection (floating vessel). The resilient connection allows the floating vessel to maintain productivity advantages while adapting to sea state conditions, preserving installation stability through controlled flexibility.
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
The resilient connection prevents resonance with wave-induced motions, reduces loads on the pile guiding system, and maintains vessel stability, even as pile dimensions increase, allowing for more efficient and stable pile installation.
Implementation Method 1
a resilient member for providing a resilient connection between the vessel and the pile during installation thereof for allowing relative motions between the pile and the vessel
Implementation Method 2
the resilient member is configured and intended to keep a natural period of a pivoting movement of the pile about the seabed caused by waves during installation thereof longer than a dominant wave period of a wave spectrum at the installation location
Data Source
AI summary
The present invention relates to an assembly for installing a pile in a seabed, the assembly comprising a vessel comprising a positioning system for keeping the vessel at an installation location relative to the seabed, the positioning system having a positioning stiffness; a pile guiding system configured to guide the pile during installation thereof, the pile guiding system comprising a base provided on the vessel; a first guiding device connected to the base, the first guiding device being configured to accommodate the pile during installation thereof; a resilient member for providing a resilient connection between the vessel and the pile during installation thereof for allowing relative motions between the pile and the vessel, the resilient member having a connection stiffness, wherein the resilient member is configured and intended to keep a natural period of a pivoting movement of the pile about the seabed caused by waves during installation thereof longer than a dominant wave period of a wave spectrum at the installation location by providing the resilient connection with a low connection stiffness.