Spring Newsletter

Articles

Using lasers to save weight

When and how will my component fail?

Developing hydrogen storage tanks

Harnessing tidal power

Are we storing up problems for the future?

What does supercritical CO2 do to my polymers?

New pipe burst test facility

MERL Oilfield Engineering with Polymers Conference 2012
 

Using lasers to save weight - Laser welding of polymers

Since adhesive bonding of most thermoplastics cannot be performed without extensive surface preparation, mechanical fastening is usually the obvious choice when using traditional joining techniques. However, a number of new joining techniques like ultrasonic, resistance or induction welding have been investigated for manufacturing reliable high performance components. Laser transmission welding is a technique with great potential for joining reinforced or un-reinforced thermoplastic components, offering the possibility of a flexible, controllable and contact free process with high automation potential.

MERL is expanding its testing and analysis expertise into assessing the strength and durability of laser welded thermoplastic components intended for aerospace, automotive and oil and gas applications. Testing and analysis methodologies developed within this programme will aim to improve the understanding of the performance of welded thermoplastic composite structures and assist on optimising their design.

For more details of the LaWocs project or other mechanical testing facilities please contact Peter Hansen

When and how will my component fail? – MERL Finite Element Services 

Finite element Analysis services are fully complemented by a wide range of testing services for generating required material model data and also for validation of analysis predictions. An example of an application of FEA for applied engineering solutions is the modelling and durability assessment of a spherical coupling joint used in rail vehicles. The use of fracture mechanics as the basis for assessing fatigue life was used. Components and structures are modelled using finite element analysis and the fracture mechanics parameters are obtained and used to calculate fatigue life.
For the fracture mechanics approach, the damage model is represented by the relationship between the rate of crack growth and the strain energy release rate or tearing energy.

The spherical coupling is subject to a complex set of fatigue conditions. The analysis methodology enabled the various parts of the fatigue loading to be assessed and the most damaging contributions and mode of failure to be identified. The approach also enabled the potential benefits of redesigning the component to be assessed. Testing the original and redesigned component enabled the analysis results to be verified. From this, a significant increase in operating life was demonstrated and the new parts are currently in service.

For more details please contact Dr Salim Mirza

Developing novel thermoplastic hydrogen storage tanks for on-board vehicle use

The partners in the TSB Durastor project include MERL, EPL Composite Solutions (Lead Partner), Crompton Technology Group Ltd, Ticona UK Ltd, Delta Motorsport Ltd, Crompton Mouldings Limited, Oxford Brookes University.

Major achievements so far include the following:

• The prototype vessel and its components have been designed.
• Vessel liners have been manufactured.
• Prototype boss components have been manufactured.
• A winding path for the reinforcement layer has been designed.
• Winding trials have now commenced.

Complete prototype vessels are expected to be manufactured by January 2012, and tests to validate their performance are expected to be completed by August 2012.

MERL’s role in the project is to perform the mechanical testing of the candidate materials (liner and composite materials) as well as testing of the finished tanks. High pressure permeation tests have been performed with 700 bar hydrogen using samples taken from injection moulded plaques of material as well as from moulded tank liners. Tests on the moulded tanks will be performed including permeation tests, burst tests, impact tests, penetration tests and a bonfire test. The test methods and facilities developed for hydrogen storage tanks will also be applicable to other high pressure tanks and pipes for other industry sectors and will compliment other MERL facilities and expertise in testing materials and products to be used in demanding environments.

For more details of the Durastor project please contact Peter Hansen

Harnessing tidal power

Tidal turbines work very much like submerged wind turbines, however, they are driven by the flow of water rather than air. They can be installed either in areas with high tidal currents or in places with continuous ocean currents to harness the energy from the vast volumes of flowing water. Increasing energy generation efficiency of these systems is very important to meet targets on renewable energy generation set by governments around the world.

The blades of the tidal turbine are generally manufactured from carbon and glass fibre reinforced composite materials and operate in a very hostile environment for extended life spans. Tidal turbines are designed for a 25 years life span and can be installed in depths of 100 m depth. They are also subjected to fatigue loading throughout their service life.

MERL has been developing suitable methodologies for predicting the fatigue life of composite elements subjected to uni-axial loading as well as the effects of seawater exposure, high cycle fatigue evaluation, adhesive bonding of dissimilar materials and designing parts with large thickness changes through ply terminations. This work builds on many years of design, analytical and testing expertise with working for aerospace, automotive and marine industry clients.

For more details on this project or other enquiries regarding fracture and fatigue testing of composites contact
Dr Stefanos Giannis

Are we storing up problems for the future? - Carbon Capture and Storage and Enhanced Oil Recovery

A Joint Industry Project (called Polymers for Enhanced Oil Recovery and Carbon Capture and Storage Applications - PECA) is being initiated in 2011 to characterise a wide range of polymers in EOR and CCS conditions to provide a materials data base with a search-and-sort front end interface.

For more details on the Joint Industry Projects or on the facilities available contact Glyn Morgan

What does supercritical CO2 do to my polymers? - CO2 Testing

When extracting oil and gas from underground, carbon dioxide is often part of the produced fluid. In recent years the amount of CO2 produced from reservoirs and the temperature and pressure at which it flows into the production system have all increased. Under these conditions, CO2 can be a supercritical fluid which behaves like a gas but has liquid-like solvating power. This has become a concern for the polymers used in components for oil and gas exploration and production because excessive swelling or change in mechanical performance of these polymers as a result of interaction with the supercritical fluid could affect their functionality.

These facilities compliment the other high pressure test facilities available at MERL that can handle most fluids and gases including sour gas, ammonia and acids. For more details on the Joint Industry Projects or on the facilities available contact Glyn Morgan

New pipe burst test facility

A common problem with performing burst (and crush) tests on composite pipe sections is the seal design used for the pressure containment. Composite pipes typically have a relatively rough outer surface which is difficult to seal onto, especially with the pressures required to burst or crush these pipes. MERL has developed a seal design which incorporates pressure-energised double seal technology, with porting in the end fittings to enable temperature (if required) and pressure to be monitored and recorded with time. The pipe is pressurised at a controlled rate until failure of the pipe is achieved. The assembly is enclosed within a secondary vessel to contain the sudden release of pressure upon failure.The current facility accommodates up to 80mm bore pipes, with burst pressures of greater than 700 bar being achieved using water as the pressurising fluid. The facility can be scaled up to accommodate larger diameter pipes according to client requirements.

For more details contact Morris Roseman

MERL Oilfield Engineering with Polymers Conference 2012

The 8th MERL Oilfield Engineering with Polymers 2012 conference provides a unique opportunity to present work to industry peers, to get up to date information on industry trends and to network with experts from oilfield operators, contractors, equipment and component manufacturers and materials suppliers.

Current themes for the 2012 conference include:

•handling of supercritical CO2
•operating in extreme environments (arctic conditions, HPHT, sour fluids etc.)
•increasing use composite materials
•development of new materials
•rapid gas decompression resistance
•qualification testing and long-term reliability.

If you are interested in presenting a technical paper at the 2012 conference then please contact Dr John Harris To be included in the mailing list for the conference please send an email to enquiries@merl-ltd.co.uk with ‘MERL Oilfield Engineering with Polymers’ in the title.