Pipe Testing Apparatus with Dynamic Lateral Actuators
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Solution Overview
Problem
Current test rigs for subsea pipelines fail to accurately simulate the mechanical stresses and strains experienced during the reeling and straightening processes, leading to unrealistic deformation and ovalization, which compromises the ability to perform effective qualification for offshore requirements.
Innovation Solution
A pipe testing apparatus with dynamic lateral actuators that apply variable transverse loads to counteract the reducing moment arm effect, allowing for controlled and programmable moment arms during reeling and straightening simulations, thereby simulating the stresses and strains more accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cantilever bending system is used to simulate reeling, then the pipe can be tested for bending stresses, but the simulation of back tension and contact bending is unrealistic
Solution Approach 1:
The test rig employs dynamic actuators that can apply variable loads and adjust their position during the test cycle. The first actuator applies axial load to simulate back tension, while the second actuator applies transverse load to simulate contact bending forces. These actuators can dynamically adjust their magnitude and direction during the reeling simulation, creating a more realistic stress state compared to static cantilever systems.
Solution Approach 2:
The patent introduces a straightening former as an intermediary component between the pipe and the test environment. This former with controlled radius of curvature serves as a mediator to guide the pipe through realistic deformation paths during both reeling and straightening phases, enabling accurate simulation of field conditions without requiring the entire reel system.
2Reliability
If the pipe is deformed to conform to reel diameter, then the stress and strain simulation is improved, but the moment arm reduces unrealistically causing excessive ovalisation
Solution Approach 1:
The test rig uses a second actuator that applies a transverse load to counterbalance the reducing moment arm effect. As the pipe deforms against the reeling former and the moment arm naturally decreases, the second actuator dynamically adjusts its transverse force to compensate for this reduction, maintaining a more realistic and constant bending moment throughout the deformation cycle. This prevents the excessive ovalisation that would otherwise occur due to the uncontrolled moment arm reduction.
3Reliability
If a four point bend system with static ends is used, then contact bending can be simulated, but the moment arm reduces during bend causing unrealistic ovalisation
Solution Approach 1:
The patent transitions from static end holders to dynamic actuators that can adjust their position and force application during the test cycle. The second actuator specifically addresses the moment arm reduction issue by dynamically applying transverse load that compensates for the changing geometry during bending, maintaining uniform ovalisation characteristics that match field conditions.
Solution Approach 2:
The test rig enables dynamic adjustment of multiple parameters including axial load magnitude, transverse load magnitude, and actuator positions during the test cycle. These parameter changes allow the system to maintain realistic stress states throughout the deformation process, particularly compensating for the moment arm reduction that occurs as the pipe conforms to the reeling former radius.
4Reliability
If back tension is applied during reeling simulation, then the stress regime is more realistic, but the system complexity increases
Solution Approach 1:
The first actuator serves multiple functions: it applies axial load to simulate back tension during reeling, provides stabilizing force during straightening, and can be adjusted to accommodate different test scenarios. This multi-functionality reduces the need for separate dedicated components for each loading requirement, thereby managing system complexity while achieving realistic stress simulation.
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 apparatus provides a more realistic deformation regime for pipe sections, reducing uneven ovalization and enabling effective simulation of in-field conditions, improving the accuracy of subsequent testing for laying and in-service performance.
Implementation Method 1
A lateral actuator is operable to apply a variable transverse load to the arm at a point distal from the pipe end connector, the variable transverse load being selected such as to counteract the moment arm reduction which would otherwise occur
Implementation Method 2
a translator to effect relative translational movement of the pipe section under test and the reeling former and of the pipe section under test and the straightening former to cause the pipe section under test to move selectively into and out of contact with and to apply a contact force against one or other of the reeling former and the straightening former
Implementation Method 3
the pipe necessarily still deforms as it comes to conform to the reel diameter, and this will still lead to stress tending to produce longitudinal strain and ovalisation in the pipe
Data Source
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AI summary
A pipe testing apparatus is described. The apparatus comprises two pipe end holders, respectively to hold a first and a second end of a pipe section under test; a reeling former; a straightening former; and a translator to effect relative translational movement of the pipe and the reeling former and of the pipe and the straightening former to cause the pipe to move selectively into and out of contact with and to apply a contact force against one or other of the reeling former and the straightening former. Each pipe end holder comprises a pipe end connector and an extending arm extending beyond the pipe end connector in a pipe longitudinal direction; and a lateral actuator is provided in association with each extending arm to apply a transverse load to the arm at a point distal from the pipe end connector. A pipe testing method is also described.