Power Umbilical Friction Profile Structure for Cable Slip Control
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Solution Overview
Problem
Existing power umbilicals face challenges in predicting and controlling the stick and slip modes, leading to excessive slip and potential damage during installation, handling, and operation, especially in applications without pre-defined suspension points, and there is a need to manage frictional forces effectively to prevent cable displacement and fatigue.
Innovation Solution
A power umbilical design featuring multiple power cables, elongated filler elements, and friction control profiles made of softer materials, which are compressed to form a ring structure, allowing controlled internal friction and preventing excessive slip by maintaining power cables apart through deformable ridges and auxiliary profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If frictional forces are increased to prevent cable displacement, then cable position stability is improved, but internal friction increases leading to excessive slip and potential cable damage
Solution Approach 1:
The filler elements are designed with different material properties in different regions: a harder outer layer providing friction control and position stability, and a softer inner layer reducing internal friction on the cable surface. This local differentiation allows the umbilical to maintain cable position while minimizing damaging friction forces.
Solution Approach 2:
The filler elements utilize composite material construction with multiple layers having different mechanical properties. The outer layer provides the necessary friction and structural support, while the inner layer reduces contact friction with the cable, thereby resolving the contradiction between position stability and friction-induced damage.
2Stability of the object's composition
If pre-fabricated suspension points are used to support heavy power cables, then cable displacement is prevented, but device complexity and installation requirements increase
Solution Approach 1:
The filler elements are designed to automatically support the power cables through their own structural properties and friction characteristics, eliminating the need for separate suspension points. The filler elements self-adjust to distribute the cable weight along the umbilical length, providing continuous support without additional complex components.
3Stability of the object's composition
If elements are fixed in stick mode to prevent sliding, then position control is improved, but excessive friction forces cause tensile rupture, buckling, fatigue, or insulation delamination
Solution Approach 1:
The filler elements provide different friction characteristics at different interfaces: higher friction at the outer surface for position control, and lower friction at the cable-contacting surface to prevent damage. This localized friction differentiation allows stick mode positioning without excessive forces that would cause cable failure.
Solution Approach 2:
The softer inner layer of the filler elements acts as a cushioning layer that absorbs and distributes friction forces before they reach the cable, preventing tensile rupture, buckling, fatigue, and insulation delamination while still maintaining position control through the harder outer layer.
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 design enables predictable friction control, reducing the risk of cable damage and fatigue, allowing for flexible installation and operation without pre-defined suspension points, and maintaining cable position under dynamic conditions.
Implementation Method 1
The one or more friction control profiles are arranged in a compressed state. The material of the friction control profile is softer than the material of the elongated filler elements
Implementation Method 2
The one or more friction control profiles are arranged in a compressed state
Implementation Method 3
maintaining power cables apart through deformable ridges and auxiliary profiles
Data Source
AI summary
Power umbilical (1) comprising a plurality of power cables (7) for electric power transmission, elongated filler elements (5), and an outer sheath (3). The elongated filler elements (5) abut against each other at abutment faces (5a), thereby forming a complete ring enclosing the power cables (7). The elongated filler elements (5) comprise cable recesses (5b) within which the power cables (7) are embedded. The power umbilical (1) further comprises one or more friction control profiles (13, 15, 116), wherein the material of the friction control profile (13, 15, 116) is softer than the material of the elongated filler elements (5). The one or more friction control profiles (13, 15) are arranged in a deformed state.