TWI is first and foremost a research organisation, investigating innovative concepts with the aim of developing improvements to processes and technologies for the benefit of our Industrial Members.
Of all the types of research that take place here, the most eclectic and experimental projects can be found in our exploratory programme. This article will introduce this strand of research, and describe some of its notable recent developments.
Types of research at TWI
Over the years our commitment to research has led to breakthroughs in many, diverse areas. Notable achievements include conducting the world’s first gas-assisted laser cut in 1967, inventing friction stir welding in 1991 and, over the last couple of years, developing full matrix capture, an advanced form of phased array ultrasonic testing, from proof of concept to commercial readiness.
Research at TWI takes several forms. Our core research programme, funded to the tune of £4 million using 50 per cent of our Membership fees, encompasses more than 50 projects each year. These projects are driven by the needs of our Members; results are published as Industrial Member reports, available exclusively to Members of TWI.
We also carry out and frequently lead publicly funded projects, most often in collaboration with other research organisations and businesses. Usually funded by the European Union or UK-based programmes such as Innovate UK, these projects seek to develop new and existing technologies, for environmental or economic gain.
Joint industry projects see us coordinate small groups of sponsors, often from within our Membership, to seek a solution to a shared problem. Pooling resources in this way allows everyone involved to reap the benefits of substantial research without having to bear the expense of conducting it singlehandedly. Then there are single client projects – confidential research carried out for individual Members. These are focused investigations tackling specific problems – the consultancy side of TWI’s business.
Separate to all of these strands of research is our exploratory research programme. This is where the ethos of innovation at TWI is most vividly represented, where our scientists and engineers are given the freedom to explore completely new ideas. Some may never progress beyond the concept stage, but others will be explored, fleshed out and assessed for viability; a small number may even grow into truly disruptive technologies.
Current areas of exploratory research
Around 40 exploratory projects are begun every year, under the headings of metal processing, non-metal processing, materials characterisation, materials testing and structural assessment.
Here we will summarise ten projects from the last 12 months; many are still ongoing, but each has already shown potential to bring tangible benefits to TWI Members. In the next Connect, we will explore one of these projects in more detail, recounting the challenges involved, explaining the chosen approach and describing the developed solution, in a technical article available exclusively to Members of TWI.
Laser metal deposition manufacturing
Although additive manufacture is seeing widespread adoption across industry, there remains no dedicated software for one of its most promising variants, laser metal deposition (LMD). TWI’s Yorkshire-based additive manufacturing team developed new computer-aided manufacturing software to plug this gap, along with a specialised five-axis control plug-in to allow creation of complex parts using a three-axis LMD nozzle in coordination with a two-axis CNC rotary table.
Electron beam additive manufacturing
Already having led to a patent, work on this project continues to develop the potential of electron beam melting, a form of additive manufacturing that uses an electron beam as a heat source to create parts with properties comparable to wrought material. The patent granted is for a novel electron beam gun that extracts electrons from a radio frequency-excited plasma, sidestepping the wear issues affecting traditional electron guns.
Thick-section aluminium friction stir welding
Twenty-five years on from its invention, friction stir welding (FSW) continues to offer opportunities for new and improved methods of fabrication. This latest work is exploring simultaneous double-sided FSW, which has the potential to weld thick-section aluminium in a single pass, drastically reducing the time required compared to the established weld-flip-weld technique.
Power cables’ unique structure has hindered the development of an efficient and effective method of joining them together. TWI has been experimenting with a new technique, based on friction stir spot welding, which promises to overcome these issues. We have already lodged a patent application and continue to refine this technology.
Examination of weld root features
This research established the cause of very shallow crack-like features occasionally found at the weld root of duplex and super duplex stainless steels. As part of the investigation TWI developed a finite element analysis model, which we used to perform thermal and stress analyses of the flaw. This led to the discovery that the flaws were a result of local tensile strain at the root.
Development of an app for calculating fugacity
Fugacity plays a major role in thermodynamic calculations, particularly at high pressures, where deviation from ideal gas behaviour becomes more likely. With companies in the oil and gas sector increasingly seeking to conduct tests in conditions that simulate high-pressure service, calculating fugacity has become an important requirement. TWI developed a web-based software tool to help its Members quickly and easily achieve this, for a variety of gases and fluids.
Testing of polymers in aggressive environments
Sometimes exploratory projects aim to improve technologies that already exist. In this project, TWI further enhanced methods of monitoring the effects of exposure of non-metals to harsh environments. One of these is permeation testing, which has been developed further to include corrosive gases at elevated pressures, water vapour, hydrocarbons (up to C8) and seawater. TWI now has facilities to apply differential scanning calorimetry and mechanical testing to assess changes in the material. Members are already benefiting from these advancements, which are now being used in single client and joint industry projects.
Hot testing of thermally sprayed aluminium
Thermally sprayed aluminium (TSA) is a well-established method of coating steels for corrosion protection, with potential for use on pipelines transporting hot fluids from oil and gas wells. However, a current lack of design codes and standards for use of TSA on hot components is limiting its take-up. This project has involved experiments to ascertain the applicability of existing standards and to understand the mechanisms affecting hot components coated with TSA.
Integrity management software
TWI’s CrackWISE software is widely used across industry to automate the fracture and fatigue assessment procedures found in BS 7910 for engineering critical assessment. The latest evolution has moved beyond the content of BS 7910, and now incorporates TWI’s specialist knowledge in this area. IntegriWISE, fitness-for-service assessment software, was also updated in this project, being expanded to include corrosion assessment to a DNV standard. These software packages continue to evolve according to the needs of industry.
Development of a corrosion-monitoring tool using pulsed eddy current technology
This project has been exploring the possibility of using pulsed eddy current technology for corrosion monitoring. So far a new pulse generator has been designed and built, capable of generating high-amplitude current with variable pulse width. This is housed in a custom frame, designed to provide 360-degree coverage of the outer surface of a pipe, and controlled using a LabVIEW virtual interface. Work is ongoing to refine the tool and move it towards market readiness.
The above ten summaries are the highlights, but together they make up less than a quarter of the total number of projects currently underway as part of TWI’s exploratory research programme.
Articles exploring these projects in depth will be published in subsequent issues of TWI’s newsletter, Connect, beginning next time with a closer look at how TWI has evolved friction stir welding to the point where it is now capable of joining thick sections of aluminium in a single pass.
To find out more about TWI’s research programmes, visit the research and innovation page, or contact us.