Riser Clamp with Reinforcement Layer for Friction and Stress Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing clamp devices for securing buoyancy elements to flexible risers face challenges due to low coefficients of friction between the outer sheath and tensile layers, leading to manufacturing difficulties and susceptibility to fracture under varying conditions such as diameter changes and bending strains.
Innovation Solution
A clamp device with a layer of resilient material and a tensile reinforcement layer, where the tensile reinforcement layer has a higher tensile modulus and strength than the clamp body, reducing flexural stress and incorporating fibre-reinforced composite materials or corrosion-resistant metals to enhance stiffness and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a rigid bodied clamp is manufactured to be a perfect fit on a riser, then the clamp provides precise dimensional fit, but the manufacturing cost increases and practical applicability decreases due to diameter variations
Solution Approach 1:
The clamp body is designed with a non-circular cross-section that can ovalise under tension, changing its dimensional parameters to accommodate riser diameter variations. This allows a single clamp design to fit multiple riser diameters without requiring custom manufacturing for each size.
Solution Approach 2:
The clamp incorporates a composite structure with a clamp body made of material having specific mechanical properties (yield strength 200-500 MPa, elongation 5-20%) that allows controlled deformation. This composite approach enables the clamp to maintain structural integrity while adapting to dimensional variations.
2Strength
If the tension band is tightened to increase clamp load capacity, then the buoyancy element support improves, but the risk of sheath tearing from underlying tensile layers increases
Solution Approach 1:
The clamp body material properties are specifically selected (yield strength 200-500 MPa, elongation 5-20%) to control the deformation behavior under tension. This allows the clamp to distribute tension forces over a larger area, reducing the risk of sheath damage while maintaining adequate load capacity.
Solution Approach 2:
The clamp body is designed to be flexible enough to ovalise under tension, allowing it to conform to the riser surface and distribute clamping forces more evenly. This flexibility reduces stress concentrations that could cause sheath tearing while maintaining the necessary clamping strength.
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 solution effectively reduces flexural stress in clamp segments, enhances load capacity, and accommodates variations in riser diameter and bending without causing fatigue or fracture, ensuring secure attachment of buoyancy elements even under harsh sea conditions.
Implementation Method 1
a layer of resilient material, preferably rubber is provided on an inner face of the clamp between the clamp body and a riser
Implementation Method 2
the tensile reinforcement layer has a higher tensile modulus and a higher tensile strength than the clamp body
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A clamp device (10) suitable for attachment to a riser is disclosed. The clamp (10) comprises a clamp body (14, 16, 18, 20), a layer of resilient material (22) provided on an inner face of the body (14, 16, 18, 20), a tensioning band (24) to secure the clamp around a riser and a tensile reinforcement layer (26) located between the clamp body (14, 16, 18, 20) and layer of resilient material (22), wherein the tensile reinforcement layer (26) comprises a high tensile modulus and high tensile strength material. The tensile reinforcement layer (26) may be laminated onto the clamp body (14, 16, 18, 20). The tensile reinforcement layer (26) may be used with any suitable clamp.