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No doubt that current FEM based multiphysics programs are state-of-the-art. The colourful Von Mises, displacement graphs, etc. are very useful and look great!
But there is one drawback. Usually they ignore effects of chemical/uv interactions with the composite matrix and reinforcements. Species solubility thermodynamics, subsequent diffusion, swelling, plasticizing, chemical activity driven chemical degradation of composite components, temporary trapping of chemicals at the matrix-filler interface, etc.: they all affect mechanical retention of polymer based materials.
For example, did you know that internal chemical driven swelling stresses can easily exceeds the design load of a polymer based construction? In the long term this situation leads to irreversible changes of the material.
Composite Agency has developed a new tool (CheFEM) which allows inclusion of chemical interactions into your FEM based composite analysis.
» CheFEM Composites Simulation
» More info on CheFEM at the JEC Composites Show in Paris (13 - 15 Apr 2010) |
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The course will provide the participants with a knowledge of fundamental principles of statistical mechanics and thermodynamics, of how to link microscopic phenomena with macroscopic properties and of how to model complex chemical systems.
The course is of relevance to researchers involved in molecular modeling, molecular thermodynamics, polymer physics and physical chemistry of fluids. People involved in process and / or advanced material design will benefit from it.
Source: Technical University of Denmark
Organizer: Technical University of Denmark
Place / Date: Denmark, Lyngby, 28 June – 9 July 2010
» Brochure on Molecular Simulation 2010
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Vikas Mittal working at BASF Polymer Research Laboratories has edited a book on nano composite physical - chemical properties. Visit the site from Wiley to learn more.
» More info about the nano composite book at Wiley
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Composite Agency completed the third and final module of the CheFEM simulation program: the Gibbs Free Restraint Module.
Short and long term service life of composites and laminates is greatly influenced by interfacial behavior between the different material components.
This new CheFEM module is based on a combination of Thermodynamic (Gibbs Free Energy) and Fracture Mechanics based analysis of interfaces. The applied concept allows - contrary to other commonly used concepts like Interlaminar Shear Strength (ILSS) - integrated analysis of interfacial behavior of the components exposed to hydrostatic / dynamic pressure and swelling driven by mass uptake and temperature gradients.
Macroscopic (Polyurethane based coating on metal), microscopic (restraint of Epoxy by Glass Fibre, also see figure below) and nanoscopic (Carbon Nanotube in Polyamide in presence of Water / other CNT composite formulations) can be evaluated without any problem. The module is also capable of incorporating chemical degradation, fatigue and ageing.
» Read more on CheFEM Simulation
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| | DNV has developed a unified approach to help ensure that CO2 is transmitted in offshore and onshore pipelines in a reliable, safe and cost-effective manner.
Det Norske Veritas (DNV) initiated the joint industry project, CO2PIPETRANS, to develop the standard one year ago. Existing pipeline standards had to be extended to incorporate specific guidelines for the transmission of CO2.The partners are ArcelorMittal, BP, Chevron, Dong Energy, Gassco, Gassnova, ILF, Petrobras, Shell, StatoilHydro and Vattenfall.
» Click here to read more at the Carbon Capture Journal
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| | Squeezing polymers into extremely thin nano layers can make them a whole lot less gas-permeable, US scientists have shown. The constrained polymer films are forced to grow as ordered crystallites, forming an effective barrier against diffusing gases.
Anne Hiltner and Eric Baer from Case Western Reserve University in Cleveland, Ohio, were actually trying to develop a selectively permeable polymer when they made their discovery. The team found that sandwiching nano layers of polyethylene oxide (PEO) between layers of poly(ethylene-co-acrylic acid) (EAA) forces the PEO to form large, crystalline nano plates that are essentially impermeable to both oxygen and carbon dioxide.
'We were originally trying to modify EAA, which is a typical packaging film resin, with PEO, which has an unusual selectivity for transporting oxygen and carbon dioxide, to try and make a film which could separate the two gases,' says Hiltner. 'What we came up with was something totally different - an exceptional change in the overall nano permeability and a whole new structure.'
» Click here to read full article by Phillip Broadwith at rcs.org
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Structural weakness forces Boeing to retrofit the 787 Dreamliner.
Boeing states that the issue with composites isn't that they aren't strong; it's that they are so internally complex. They consist of layers oriented in different directions; those layers, in turn, are made of individual fibers that may vary somewhat in composition. This makes it difficult for engineers to accurately mimic their performance in computer models for premanufacture testing.
» Article by D. Talbot on Technology Review
» Read more on the CheFEM Multilayer Tool
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A new way of printing organic electronics is more reliable and yields higher performance. The interface behaviour (which is also important for diffusive transport and permeation properties) is improved to a substantial extent. Read the following introduction by Katherine Bourzac:
It is possible to print large, flexible arrays of cheap, plastic transistors to drive displays. But the performance of these organic electronics is still not consistent enough for commercial devices. A new method for printing a wide variety of semiconducting organic compounds such as polymers is much more reliable - and on top of that, it improves the performance of a wide variety of these materials by a few orders of magnitude.
» Complete story at the site of Technology Review by Katherine Bourzac
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A Beta version of CheFEM is under way. CheFEM is our unique integrated permeation - chemical resistance - mechanical prediction tool for polymer based materials.
The new standard version will be using Sanchez - Lacombe - a more extensive lattice based model - equation of state for prediction of solubility thermodynamics of sub- and supercritical chemicals in polymers, coatings and composites. In combination with existing free volume and Maxwell-Stefan based diffusion calculations, permeation and degradation mechanism can be predicted more rigorously.
Secondly, the machine routines for multilayer diffusion and mechanical retention calculations have been made more efficient: concentration profiles, time lags, etc. can be derived and graphed much faster.
Last but not least: the interface with data obtained from laboratory experiments has been improved. For example continious measurement data from ASTM E96 test, Mocon test equipment, Dynamic Vapour Sorption tests, or stress and strain test data can be imported straight forward and fitted to the advanced models.
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| | By a miracle no one was injured after the end of the afternoon a wing of a windmill broke off and landed on the motorway A6. The rotor blade that broke from the windmill belongs to a series along the highway near the Flevo power station. The colossus of 20 meters came onto the right lane of the motorway A6. The age of the NUON blade is around 12 years.
You probably wonder whether something similar has happened before. Yes, it did, and quite nearby, in the Netherlands (for the dutch readers follow this link: Article Webregio.nl). Please contact us for similar cases.
Windmill rotor blade at the A6 motorway, Lelystad, The Netherlands.
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In March 2009 Pamela Waterman published an interesting article "Composite Analyis: Making New Choices: An Engineering Design Guide to Choosing Software for Working with Today's Composite Materials" on Desktop Engineering Online.
» Click here to read the overview article (please note the various links at the footer of the article).
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| | Water vapour condensation on - and diffusive transport in - thin polymer based flexible solar cell films can give rise to several physical-chemical failure modes, such as swelling stresses on interfaces, reduced impact resistance (Tg depression), blister formation driven by osmotic pressure or chemical degradation of another laminate component.
In this in-house project, properties of transparent Polyimide substrates are researched, with the objective to enhance lifetime and to increase solar cell efficiency. Among others, the high glass transition temperature, low free volume and excellent UV resistance, make Polyimide an attractive concept material for flexible thin film solar cells. However, in real life circumstances, water and oxygen mass diffusion must be evaluated rigorously for sake of solar cell (photovoltaics) lifetime predictions and proper design of accelerated laboratory tests.
Composite Agency uses CheFEM and Abaqus (impact) for modelling, Dynamic Vapour Sorption and several Peel/Pull test set-ups for validation and assessment of accelerated weathering service life analysis solutions. Do not hesistate to contact ir. drs. Sijmon van der Wal for more information regarding this solar cell initiative of Composite Agency.
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» 14 July 2009: Book of Abstracts (pdf, 4 Mb)
During June 24-26 the 5th Internatial Conference on Diffusion in Solids and Liquids, Mass and Heat Transfer, Diffusion in Nano and Nanostructured Materials will be held in Rome-Italy.
With regard to Mass Transfer the following topics are discussed: Basics of diffusion, Carburisation and Nitridation, Internal precipitation, Alloy heat treatment, Particle growth and coarsening, Microstructural and crystallographic texture evolution, Reactive diffusion,Phase transformations, Multiphase diffusion systems, Microelectronic and nanoscale systems, Interfaces, Diffusion in crystalline & amorphous materials, Diffusion in ultrafine grain & nanocrystalline materials, Diffusion in porous media,Surface oxidation and corrosion, Phase diagrams, Ad- and ab-sorption, Diffusion coefficients, Solute trapping at solid liquid interfaces, Mathematical modelling,Numerical methods, Experimental methods and Industrial applications.
Regarding Nanodiffusion and Nanostructured Materials: Nanomaterials, Nanocomposites, Biomaterials, Industrial applications.
Regarding Microstructure & Properties: Mathematical modelling, Numerical methods, Experimental methods and Industrial applications.
Concerning Heat Transfer: Mathematical modelling, Numerical methods, Experimental methods and Industrial applications.
Composite Agency is looking forward to meeting you on this ultimate conference for everyone directly or indirectly involved in diffusion phenomena.
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Do you have to perform a quick permeability or another physical - chemical oriented calculation? Are you on a congress and wondering why the presenter is so enthusiastic about the results, while you and your colleague are unable to quickly interpret the units he / she is showing to you?
No problem from now on, use our brand new online unit converter!
Click here to activate. Good luck.
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The newsletter contains brand new industrial case studies and hot topic discussion updates selected by experts. To sign in, enter your e-mail address and press the "subscribe" button.
Note that the letter is free of any obligation and that your e-mail address is treated strictly confidentially.
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What is the lifetime of a Fibre Reinforced Plastic (FRP) laminate for containment purposes exposed to an alkaline solution with pH 14? Seemingly a trivial question, because this FRP product exists already more than 50 years. However, lack of computing capacity (FEA and FDA) in the near past still makes this question actual.
Problem is that glass fibres are degraded by Sodium Hydroxide on the long run. But is this an issue if the Sodium Hydroxide is strongly diffusion hindered by a boundary of corrosion resistant resin? Currently, we are simulating the diffusion of a Sodium Hydroxide solution through the FRP laminate. The multilayer laminate consists of a 100% Vinyl Ester (VE) resin boundary layer and a second layer containing glass fibres (55 vol%, E-glass) and VE resin (45 vol%).
Computer simulations reveal that the lifetime is strongly dependent on the thickness of the boundary layer, the thickness of the second layer and the degree of Alkalinity. If the boundary layer has a thickness of 50 micrometer, and the second layer is 3000 micrometer thick, the lifetime already exceeds a 40 years at ambient temperature and pressure. At pH 12, the service life is even more than 100 years. Key factors are proper shielding of the glass fibres by boundary resin and low temperature (25 degrees Celsius) to prevent capillary uptake and swelling phenomena.
Note that in many accelerated laboratory testing set-ups, the temperature is increased. In our case, this would unjustly introduce swelling strain on the fibre matrix interface, generating lifetimes magnitudes shorter than the ones obtained here.
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It is widely recognized that shelf and service life of various polymer based electronic equipment is largely dependent on UV resistance and diffusion barrier properties. Examples are light / video displays and solar cell components.
Nevertheless, diffusion analysis is usually carried out using the layman's equations: Fick's Laws. In addition and paradoxally, current use of FEA simulation software is leading to an increasing use of Fick's laws in all kinds of - in itself state-of-the-art - simulations. This is probably due to the often suggested plain analogy between FEA computed Fourier equations for heat transport, and Fick's Law for diffusion. However in our opinion, this analogy between Fourier and Fick is only valid in 1% of the industrial simulations, at least when polymer based materials are involved.
In this new case study "Evaluation of Transparent Polyimide for Flexible Solar Cell Substrates", it is shown that already small deviations from Fick's laws result in fundamental material decisions.
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| | Date: 3 October 2008
Location: Aula Congress Centre - Delft University of TechnologyComposite Agency is pleased to inform you on the Offshore Symposium organized by the Offshore Engineering Student Association DOT. Presentations include topics by reputable experts on Deep Sea Installations, Offshore Production of Stranded a Natural Gas resources that are currently not used for economic/technical reasons Gas, Wind Turbines Installation Offshore, Carbon Dioxide Storage Opportunities, etc.
website: www.dot.tudelft.nl.
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| | You may be interested in participating in a one-day workshop organised by the IOP Printing and Graphics Science Group and the UK Displays and Lighting Network:
Gas and Moisture Permeation Measurement for High Barrier Films
at Institute of Physics, London
on Thursday 25th September 2008
There are many instances where flexible films are being used because of their conformal nature or transparency. While many materials provide near ideal optical and mechanical properties, their barrier and chemical resistance properties often need to be improved to provide useable service life. For example in plastic electronics, many of the promises of flexible plastic Organic Light Emitting Diodes (OLED) and Photovoltaics (PV) can only be realised by having a substrate with superior barrier properties. This raises the issue of barrier measurement since any measurement systems needs to have at least 1 order of magnitude better resolution than the barrier properties being measured.
This joint workshop aims to improve understanding in the area of barriers and their measurement. It will be of interest to scientists developing barrier layers for films, and using or improving permeability testing equipment. The meeting will include presentations from:
* Holgor Norenberg, Technolox
* Hazel Assender, University of Oxford
* Stephane Cros, CEA, France
* Sharon Louch, CPI
* Jasper Michels, Holst Centre, The Netherlands
* Sijmon van der Wal, Composite Agency, The Netherlands (see abstract below)
For details regarding the event (including a form to register online) please see the workshop web page, or contact Eifion Jewell of UKDL at eifion@ukdisplaylighting.net
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Composite Agency is present on Composite & Lightweight Structures in Aircraft - Design and Manufacturing - more |
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Our latest software on lifetime predictions of reinforced and multilayer materials will be presented at JEC 2008 - Forum for Building & Construction, on the 2nd of April 2008 in Paris. Click here to download the preliminary version. Click here to go to the JEC Composites 2008 website. |
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Via this special video we would like to wish you a happy & prosperous 2008! |
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We have been active in material selection for automotive applications since 2003. For the subsequent stages of composite implementation, such as manufacturing, assembly, visit our partner site at: composites engineering. |
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The successor of Glare is on it's way to space: CentrAL. CentrAL is an aerospace material from the Fibre-Metal-Laminate (FML) class: a lightweight Aluminum - Glass Fibre - Epoxy composite. CenrAL exhibits good ageing characteristics, mainly because of its intrinsic capability to stop impact or ageing crack growth before reaching the critical (Griffith) crack size. Compared to carbon-epoxy composites, mechanical strength under continuous load from torsion, tensile and flexural stress of CentrAL is better. However, the interfacial behaviour of fibre-metal-laminates when exposed to atmospheric water in varying environmental conditions is very probably less than carbon - epoxy composites.
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The 11th International Elastomer Seminar 2007 will be held in Freiburg , Germany from 23 until 27 September 2007. Among other subjects, ageing, fatigue and lifetime of composite elastomers will be discussed. More information on the website of dkg-rubber.de
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The first international conference on self healing materials will be held on 18-20 April 2007 in Noordwijk, the Netherlands. Visit website to learn more.
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We will present our most up to date programmes on life time assessment on the Third International Conference on Durability & Field Applications of Fiber Reinforced Polymer (FRP) Composites for Construction. Details: 22-24 May 2007, Loews Le Concorde Hotel, Quebec City, Quebec, Canada. Click here for more info.
[Archive] paper
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Technical glitches and manufacturing woes could delay Boeing's breakthrough.
For Boeing, the 787 Dreamliner, with its radical lightweight design, represents far more than a potentially juicy profit stream. Made from carbon-fiber-reinforced plastic, the aircraft is supposed to be the symbol of a new Boeing... read more. |
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The agency will be present at the 22nd European Symposium on Applied Thermodynamics from 28 June 2006 until 1 July 2006 in Elsinore - Denmark. J.S. van der Wal will give a presentation on the thermodynamics and diffusion of atmospheric water in high performance composites. Specific attention is given to the behaviour of water in the composite, when the temperature in the atmosphere variates from - 70 to + 50 degrees Celsius. More details are available on the site of esat 2006.
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Sijmon van der Wal will give a talk on diffusion and chemical resistance of (reinforced) plastic containment materials. Special attention is given to Hydrogen and LPG losses from tubes and reinforced tanks when water diffuses into the opposite direction from the atmosphere. The Automotive Fuel Containment 2005 will be held on 6 and 7 December 2005 in Hannover, Germany. Conference is organized by Rapra Technology.
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