Composite Auxiliary Riser Conduit for Bending Load Management
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Solution Overview
Problem
Conventional drilling riser systems face challenges with excessive bending loads leading to tensile and compressive forces, potential failure, and weight issues due to thick wall construction, especially in deep water environments, where metallic components exhibit high axial stiffness and misalignment problems during assembly.
Innovation Solution
A riser system featuring a primary conduit and auxiliary conduits made of composite materials with reinforcing elements, connected via a connecting portion that allows for load sharing and deformation accommodation, reducing stress and weight, and enabling pre-tensioning to support the primary conduit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic components with high axial stiffness are used, then strength is improved, but the risk of failure under bending loads increases
Solution Approach 1:
The patent changes the material parameter from metallic to composite, fundamentally altering the stiffness characteristics. Composite materials have lower axial stiffness compared to metals, allowing the auxiliary conduit to flex and accommodate bending loads without transmitting excessive forces to connection points, thereby reducing failure risk while maintaining adequate strength
Solution Approach 2:
The patent explicitly employs composite materials for the auxiliary conduit instead of traditional metallic materials. This composite construction provides the necessary strength-to-weight ratio while offering lower axial stiffness that allows the conduit to deform elastically under bending loads, preventing catastrophic failure that would occur with rigid metallic components
2Strength
If thick wall construction is used to support tensile forces, then strength is improved, but weight increases
Solution Approach 1:
Composite materials provide superior specific strength (strength-to-weight ratio) compared to metallic materials. The auxiliary conduit constructed from composite materials can support the required tensile forces with significantly reduced wall thickness and overall weight, making the system suitable for deep water applications where weight is a critical constraint
Solution Approach 2:
The patent changes the material composition parameter from metal to composite, which fundamentally improves the strength-to-weight ratio. This parameter change allows the auxiliary conduit to achieve the necessary tensile load-bearing capacity with much lighter construction, directly addressing the weight reduction requirement
3Force
If rigid connection is used between primary conduit and auxiliary conduit, then load transfer is improved, but adaptability to deformation decreases
Solution Approach 1:
The patent changes the material parameter of the auxiliary conduit from metallic to composite, which fundamentally alters its mechanical response. The composite material's lower axial stiffness allows the conduit to deform elastically under load, accommodating bending and movement while still providing adequate load transfer through the connection points
Solution Approach 2:
The patent creates a dynamic system where the auxiliary conduit can deform and adapt to changing load conditions. The composite construction allows the conduit to flex and move with the primary conduit during bending operations, rather than maintaining a rigid fixed position, thereby improving adaptability while maintaining load transfer capability
Data Source
Figure 1
Figure 2~3
Figure 4A~5B
AI summary
A riser system configured to be secured between a surface vessel and a subsea location comprises a primary conduit and an auxiliary conduit extending adjacent the primary conduit, wherein the primary and auxiliary conduits are connected together at an axial location along the riser system via a connecting portion. The auxiliary conduit comprises a composite material formed of at least a matrix and one or more reinforcing elements embedded within the matrix.