Damping Testing Apparatus for Slender Umbilicals
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Solution Overview
Problem
Current methods for evaluating the damping characteristics of slender structures like umbilicals and flexibles in underwater oil and gas field development are inadequate due to oversimplified linear assumptions, failing to accurately capture the complex non-linear damping behavior of these structures under external forces such as underwater currents.
Innovation Solution
A damping testing apparatus and method involving a testing platform with pivot pins, hydraulic cylinders, and extendable arms to apply controlled tension and vibration to the structures, allowing for precise measurement of lateral deflection and derivation of damping coefficients across varying tension levels and vibration parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If linearized approximation is used to estimate damping, then the analysis is simplified, but the accuracy of damping characteristics is insufficient
Solution Approach 1:
The patent replaces complex mechanical vibration testing with a controlled tensioning system that applies static or dynamic tension to the umbilical sample. The system uses a tensioning apparatus with adjustable weights or springs to create controlled tension states, allowing measurement of damping characteristics without complex mechanical vibration equipment. This substitution enables accurate measurement while maintaining analytical simplicity.
Solution Approach 2:
The patent systematically varies the tension parameter in the umbilical sample to capture non-linear damping behavior. By changing tension from zero to maximum operating tension and measuring damping at multiple tension levels, the system reveals how damping characteristics change with tension. This parameter variation approach provides accurate damping data while keeping the testing method relatively simple compared to full mechanical vibration systems.
2Measurement precision
If complex non-linear damping behavior is captured, then the accuracy of damping characteristics is improved, but the testing apparatus becomes more complex
Solution Approach 1:
The patent extracts the essential damping measurement function from complex mechanical vibration systems. Instead of using complete vibration testing equipment, the invention isolates the damping measurement capability by using a simplified tensioning apparatus with controlled weights or springs. This extraction allows accurate damping measurement while significantly reducing apparatus complexity.
Solution Approach 2:
The patent employs simple, easily replaceable tensioning elements such as weights or springs that can be quickly adjusted or replaced. These simple components provide the necessary tension control without requiring complex, expensive, or difficult-to-maintain mechanical vibration systems. The simplicity of these elements reduces overall apparatus complexity while maintaining measurement accuracy.
3Ease of manufacture
If damping is assumed to be linear at fixed percentage, then the analysis is simplified, but the ability to identify damping characteristics under varying conditions is lost
Solution Approach 1:
The patent transitions from static linear damping assumptions to dynamic tensioning that captures non-linear behavior. The system applies tension dynamically or statically at multiple levels and measures damping response at each level. This dynamic approach reveals how damping varies with tension, providing adaptability for different operating conditions while maintaining analysis feasibility through systematic measurement procedures.
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
Enables accurate determination of damping characteristics, aiding in optimization and application of slender structures by providing a more nuanced understanding of their vibration responses, moving beyond linear approximations.
Implementation Method 1
The extendable and retractable arm can be a hydraulic cylinder
Implementation Method 2
activate the two hydraulic cylinders that control the movement of the testing platform to vibrate the testing platform in predefined amplitude and period
Implementation Method 3
derive the damping coefficient from the testing sample lateral deflection amplitude
Data Source
AI summary
Apparatus and methods related to damping testing are disclosed. For example, some embodiments may contain a testing platform supported on wheels and moveable by hydraulic cylinders, and two fasteners for fastening the testing sample, one fixed on the testing platform and the other moveable along the testing platform by another hydraulic cylinder, and may be used for the damping testing of slender structures such as umbilicals and flexibles used in oil and gas underwater field development.