Joint Industry Projects (JIPs)
Our joint industry projects (JIPs) allow interested parties to come together as project sponsors, pooling resources for greater research outcomes, while also being given exclusive access to the results and the opportunity to guide the direction of the project itself.
These projects typically focus on particular challenges faced by specific industry sectors, providing industry-relevant information, guidance and solutions.
- Investigation into High-Grade Mooring Chain Fatigue Resistance
Demand from industry had stimulated the need for test data, under realistic conditions, to better understand the fatigue performance of R5 grade steel mooring chains of larger links than were covered by existing design recommendations. TWI worked alongside Industrial Members from the offshore oil and gas sector to investigate fatigue in mooring chains, using a unique test rig designed and built at TWI (Figures 3-4). The project, which ran from 2012 to 2018, provided fatigue design data as an update for recommendations that were based on data from the 1990s that used chains of a relatively small diameter and low steel grades. A later comparative study was also undertaken based on this project for the wider benefit of our Industrial Members as part of the core research programme (see above).
Full-scale testing data has also been instrumental in several pipeline-related JIPs, investigating flaw tolerances, sour service conditions, plastic strain at welds, fatigue performance, and more.
Example projects include:
- Flaw Tolerance in Pipeline Girth Welds Subjected to Axial Straining and Internal Pressure
Full-scale pipe testing was used to validate procedures for assessing flaw tolerance of pipeline girth welds at post yield strains, with and without internal pressure.
- Improved Welding, Inspection and Integrity of Clad Pipeline Girth Welds
Full-scale test data was used as part of this review of linepipe manufacturing methods and their effect on installation welding and non-destructive testing.
- CRA Plastic Strain - Corrosion Resistant Alloys: Simulating Strain at Welds for Cracking Resistance Qualification Testing
This project sought to address environmentally-assisted cracking behaviour of strained, welded supermartensitic and superduplex pipe to understand / predict full-scale testing behaviour.
- Fatigue Behaviour of Lined Pipes
Mechanically-lined pipes are cheaper than clad pipe as well as being easier to manufacture. These pipes use a liner that is often secured at the ends with weld overlay cladding, allowing girth welds to be produced between sections of lined pipe in the same way as clad pipe. However, there is a risk of failure where the weld overlay interfaces with the liner when the pipe is subjected to fatigue loading. To account for this, TWI conducted this two-year project to provide designers with data on the fatigue strength of lined pipe with weld overlay. This work included full scale testing to measure the fatigue performance of mechanically lined pipe ahead of the development of an ultrasonic inspection technique and approaches for engineering critical assessment (ECA) and finite element analysis (FEA).
- Fatigue Design Guidance for Risers in Sour Service via Full Scale Testing
Fatigue performance is a critical factor in the design of steel catenary risers (SCRs) in deepwater oil and gas developments. While resonance fatigue tests of full-scale girth welds had become standard industry practice to demonstrate adequate performance, these tests did not account for aggressive service environments such as sour production fluids. Instead, the resonance fatigue tests were followed by strip fatigue testing to determine the fatigue life ‘environmental knock down factor’ (EKDF) that was then applied to the base design curve. Despite its use by industry, the validity of this approach had not been demonstrated, so we created a JIP to address this gap and provide a better understanding of the sour performance of girth welded riser pipe. The project developed a method for performing fatigue tests on full scale welds in pipes containing a sour environment, with the results then compared to the results of full-scale resonance fatigue tests, strip tests in air, and strip tests in a sour environment. Detailed investigations, including examination, residual stress measurements, fatigue crack growth rate measurements and fracture mechanics assessments showed that the EDKFs from direct comparison of full-scale tests were found to be lower than with the existing testing regime. The project produced commentary on the approach used as well as significant results and observations, and validated guidance for design of risers. This project required the design, build, and configuration of a unique custom rig for full scale resonance fatigue testing in sour environments at TWI (See Figures 5-6).
- Effect of Impurities on CO2 Transportation Pipelines (ENCO2RE)
A more recent project was created to investigate the efficient transport of CO2 from emission sources to storage sites or utilisation facilities for carbon capture, utilisation and storage (CCUS) purposes. Captured CO2 is often contaminated with impurities that can affect its thermophysical properties and flow behaviour during pipeline transportation. This project addressed several associated issues, including detecting acid drop out, how acid drop out and water contamination could affect pipeline corrosion behaviour, and how to limit the concentration of certain impurities to reduce acid drop out.
Public-Funded Projects
Our expert teams are also called to participate in public funded projects in partnership with other organisations from industry and academia to solve specific challenges, typically for particular industry sectors.
- DeICE-UT: Anti and De-icing Turbine Blades
This two-year collaborative project investigated a solution to ice build-up on wind turbine blades through the use of a dual de-icing system that combines high-power ultrasonic guided waves (UGW) with low-frequency vibrations (LFV). The aim was to remove already formed ice while also preventing further ice accumulation at temperatures down to -20°C (although tested to -30°C). A prototype system was created and then tested, both as a section of a full-scale wind turbine blade (to validate the LFV) and a small-scale mock-up (to validate the leading-edge UGW) (See Figures 7-8).
- Wrapsense: Hydrocarbon Leakage Detection Technology
This project, funded by Innovate UK, saw us work with Canadian SME, Direct-C, to assess the performance of their highly sensitive WrapSense technology for detecting leakages in oil and gas and aerospace applications. TWI provided both small and large-scale testing to validate the capabilities of technology for industry, including a full-scale 6-month environmental test where the system was exposed to six months of winter weather. The pipe, a 300mm OD steel pipe, was fitted with ten 1-metre-long sensors and connected to an Internet of Things controller unit that transmitted data from the sensors hourly. Meanwhile, a wireless weather station was installed alongside the pipe to correlate conditions including temperature, wind direction, wind speed, rainfall and humidity as well as any environmental damage to the sensors’ readings, to ultimately assess the sensors’ performance (Figures 9-10). The technology was also tested on commercially-available hydraulics (Figure 11) to see if it was capable of detecting hydrocarbons in aviation hydraulics.
Dedicated Industrial Member Support and Other Projects
Much of the work undertaken at TWI is on behalf of individual Industrial Member companies, with much of this work being necessarily confidential. However, there are some examples of these types of project work, including full-scale testing, that we are able to share with you…
- Full-Scale Resonance Testing of Subsea Connectors to Predict Fatigue Capacity
TWI Industrial Members, Aker Subsea wished to confirm fatigue design calculations for their subsea connectors, so we assisted by conducting full-scale resonance fatigue tests to locate failures and assess the connectors’ fatigue strength. The tests were designed to recreate the cyclic loading under controlled conditions, which could then be compared to finite element analysis (FEA) models to validate the FEA predictions and check for discrepancies so the FEA models can be updated and reassessed. TWI was provided with two 7m long specimens containing four connectors for the full-scale testing (Figure 12). The bespoke testing regime included resonance fatigue testing using strain gauge readings to indicate cracking before the connectors were opened and dye penetrant testing was carried out along with magnetic particle inspection on the fatigue critical locations, indicating a number of cracks in locations that had not been highlighted by the FEA (Figure 13). However, the results showed that the connectors had a higher fatigue strength than the design suggested and the previously identified fatigue critical locations did not crack. This work allowed Aker Subsea to re-evaluate the criteria used in their finite element models and calculations for fatigue life, based on the results of the full-scale fatigue tests.
- Qualification of Reeled Mechanically Lined Pipes for Fatigue Service
Full-scale resonance fatigue testing was also employed for a project for TWI Member company Technip, who had designed a mechanically lined pipe (MLP) system that enabled reel-lay installation under atmospheric pressure without the risk of wrinkling the corrosion-resistant alloy (CRA) lining. TWI conducted the full-scale tests along with non-destructive examinations, such as dye penetrant inspection (DPI) and eddy current testing (ECT), to qualify these new reelable MLPs and provide further evidence that a high fatigue performance can be reached without breaching the CRA liner. Testing was conducted on six 5m long MLPs, which were previously subjected to reeling at atmospheric pressure, in order to qualify the fatigue performance to DNV fatigue curves (DNV, 2012). Additional tests were carried out using DPI and ECT at the interface between the clad overlay weld and the liner, 2.5m from the pipe end, to detect cracks (Figures 14-15).
- Detection of Liner Cracking in Mechanically Lined Pipes
Our research into the detection of cracking in the liner of mechanically lined pipe (MLP) continued with a new project that simultaneously involved full-scale resonance fatigue testing. This would allow the fatigue performance of the liner to be assessed before the carbon steel backing pipe is exposed. In this project, full-scale fatigue testing was carried out on a 5.9m long MLP that contained one girth weld at mid-length with weld overlay on either side of the girth weld. The liner was welded to the weld overlay and extended to approximately 200mm from the specimen ends, where it was sealed with a fillet weld. A system for detecting leakage was developed using ‘wet detectors’ (absorbent material connected to wires, connected to the test machine trip circuit) fitted to two carefully positioned holes in the carbon steel pipe wall (located towards each pipe end). To aid distinguishing between condensation and fluid from failure, a green colorant was also applied. The test stopped once the thickness of the liner cracked and before the crack reached the pipe through thickness, as indicated by the strain gauge readings (Figure 16).
- Full-Scale Testing of a ‘Rocksteady’ Connector
TWI Industrial Member company, Subsea Riser Products (SRP) had developed a new position mooring system, called the ‘Rocksteady’ connector, for offshore vessels, including a design with pre-tensioned ‘fingers’ that enhanced its fatigue resistance. Our expert team produced test-specific risk assessments and agreed a test procedure for the connector to meet demanding qualification requirements, including the application of static tensile loads of 9900 kN (1010 tonnes), fatigue loading at three different load levels, and a test involving disconnecting the connector while under a tensile load. Because SRP also wished to measure the strain experienced by the fingers in the connector during the application of the pre-load, and during the external load tests we also applied strain gauges to the fingers. We created a test machine capable of applying a static load of up to 1010 tonnes, and fatigue loads of up to 500 tonnes before conducting static proof tests, fatigue testing, a static minimum break load test and a static disconnect under load test (Figures 17-19). The strain experienced by the connector was recorded throughout and the project team analysed the data so that the measured strain values could be compared with the values predicted by SRP’s finite element models, concluding that the Rocksteady connector could withstand the applied loads without damage, and it was fit for use.
- Resonance Fatigue Testing in TWI’s Pressure Pit Facility
TWI Industrial Member, Petrofac contacted us in relation to undertaking a series of resonance fatigue tests on thick-walled pipe as part of design work for a gas injection pipeline with a design pressure of 600bar and a pipe wall thickness of nearly 60mm. The aim of the test was to ensure the fatigue strength of the welds to make sure the pipe could withstand in-service fatigue loads. Six specimens were provided for testing against the BS7608 Class F2 fatigue design curve, ensuring that the weld root was in tension throughout the tests by applying a mean stress via internal water pressure. Since the pipes were thick walled, a high internal pressure (16,800psi, 1158bar) was required to produce a 100MPa axial mean stress. The large pipe diameter meant that the stored energy associated with the pressurised water was greater than could be accommodated within our standard safety containment frames, so the resonance testing machine was relocated to our pressure pit test facility for this work. Five of the six tests ran until through-wall cracking occurred (See Figure 20), with the results showing that the welds met the required fatigue performance.
- Variable Amplitude Resonance Testing of Girth Welds
TWI regularly conducts full-scale fatigue testing on girth-welded pipe from steel catenary risers (SCRs) and pipelines for our Industrial Members to ensure welds have sufficient fatigue strength. To provide greater confidence among our Members in the integrity of their assets, we developed a new fatigue testing technique to test full-scale girth-welded pipes under variable amplitude (VA) loading. The research project aimed to develop a method for fatigue testing of full-scale girth-welded pipes under a loading spectrum representative of that experienced by SCRs (Figures 21-22).
You can find out more about full-scale testing support at TWI, here: https://www.twi-global.com/what-we-do/services-and-support/full-scale-testing