Faye C.,Technological Institute FCBA |
Verdret Y.,Technological Institute FCBA |
WCTE 2016 - World Conference on Timber Engineering | Year: 2016
Seismic performance-based design of a structural system must ensure performance objectives of the structure against natural hazards like earthquakes. This design philosophy has widely been developed for reinforced concrete, steel buildings or bridges built in high seismic areas. This paper proposes a vulnerability analysis on timber shear walls with stapled diaphragm (OSB 12 mm thick) under seismic action. Vulnerability analysis is based on the use of the Nonlinear Spectral Method N2 which predicts timber frame wall displacement and acceleration by taking into account the ductile behaviour of structures. In a first part, the application of the Nonlinear Spectral Method on seismic behavior of conventional timber frame walls showed that displacement on the top of the wall is well estimated. In the second part, a vulnerability analysis of timber frame walls under seismic action based on Non linear Spectral Method is developped by taking account of material and seismic action uncertainties. Fragility curves show that, for seismic actions of which PGA is 0.3g, no structure reaches the second limit state.
Sharma D.,French National Center for Scientific Research |
Erriguible A.,I2M |
Amiroudine S.,French National Center for Scientific Research
Theoretical and Computational Fluid Dynamics | Year: 2017
The forces acting on a solid body just at the time of impact on the surface of a medium with very low compressibility, such as water, can be quantified at acoustic time scales. This is necessary in wide range of applications varying from large-scale ship designs to the walking or running mechanisms of small creatures such as the basilisk lizard. In order to characterize such forces, a numerical model is developed in this study and is validated using analytical expressions of pressure as a function of the speed of sound-wave propagation in water. The computational results not only accurately match the analytical values but are also able to effectively capture the propagation of acoustic waves in water. The model is further applied to a case study wherein the impact impulse required by the basilisk lizard to assist in its walking on the water surface is evaluated. The numerical results are found to be in agreement with the closest available experimental data. The model and approach are thus proposed to evaluate impact forces for wide range of applications. © 2017 Springer-Verlag Berlin Heidelberg
News Article | December 8, 2016
BONN, 08-Dec-2016 — /EuropaWire/ — DHL Global Forwarding, the air and ocean freight specialist of Deutsche Post DHL Group, and Mubadala Development Company, the Abu Dhabi-based investment and development company, initiate a strategic partnership for the next five years. With its unique logistics expertise and portfolio DHL will support globalization and growth as well as deliver value across Mubadala Aerospace assets, their customers as well as Abu Dhabi as a whole, by aligning all logistics related processes efficiently and replicable. “With this new strategic partnership we as DHL can demonstrate our expertise as an innovative lead logistics partner. Our solution enables the end-to-end management of Mubadala’s supply chain creating visibility across all assets in scope”, describes Claudio Scandella, DHL CEO Middle East & Africa. Mubadala is looking to transform their inbound to aerospace manufacturing logistics (I2M) as well as their maintenance, repair and overhaul (MRO) material flows. DHL’s innovative solution brings this desired outcome by streamlining all logistics process flows of Mubadala Aerospace assets horizontally, leading to an efficient, effective and replicable modality. This way the need for customization of individual assets is reduced. The approach ensures continuous visibility, control and improvement. Homaid Al Shimmari, Chief Executive Officer, Aerospace & Engineering Services, Mubadala, said: “Mubadala’s aerospace and information communications technology companies are operating at the heart of global supply chains, where timely and efficient delivery is critical to ensuring competitiveness. As Abu Dhabi’s aerospace cluster develops at the Nibras Al Ain Aerospace Park, with new companies being established with our global OEM partners as well as the expansion of our current businesses, a robust supply chain supported by DHL, will be an essential part of future success.” This strategic partnership is designed to bring optimized logistics, speed of change and cost reduction to all assets and customers of Mubadala across the globe in a multi modal manner. Approximately 66 percent of the cargo volume transported in the course of Mudabala’s partnership with DHL will be air freight.
Zhao Y.F.,McGill University |
Perry N.,Arts et Metiers ParisTech |
Re-Engineering Manufacturing for Sustainability - Proceedings of the 20th CIRP International Conference on Life Cycle Engineering | Year: 2013
Manufacturing firms that wish to improve their environmental performance of their product, process, and systems are faced with a complex task because manufacturing systems are very complex and they come in many forms and life expectancies. To achieve desired product functionalities, different design and material can be selected; thus the corresponding manufacturing processes are also changed accordingly. There is direct need of assessment tools to monitor and estimate environmental impact generated by different types of manufacturing processes. This research proposes a manufacturing informatics framework for the assessment of manufacturing sustainability. An EXPRESS information model is developed to represent sustainability information such as sustainability indicators and their associated weighting and uncertainty factors, material declaration information, and hazardous condition information, etc. This information model is tested with industrial products to validate its completeness and correctness. This information model serves as the first step of establishing close association of sustainability information with product design specification. In the next phase of research, investigation will be conducted to integrate sustainability information model and existing standardized product design model ISO 10303 AP 242.
Camenen J.-F.,I2M |
Richard P.,LUNAM University
Geomechanics from Micro to Macro - Proceedings of the TC105 ISSMGE International Symposium on Geomechanics from Micro to Macro, IS-Cambridge 2014 | Year: 2015
We investigate numerically granular piles exhibiting steady surface flows. A vertical monolayer of frictional grains is confined between two vertical sidewalls. Above a critical flowing rate and in agreement with experiments (Taberlet, Richard, Valance, Losert, Pasini, Jenkins, & Delannay 2003), surface flows at inclination larger than the angle of repose appear. Below these surface flows, particles exhibit a very slowcreep motion whose velocity decays exponentially with depth (Lemieux & Durian 2000, Komatsu, Inagaki, Nakagawa, & Nasuno 2001, Crassous, Metayer, Richard, & Laroche 2008). Here, we focus on the correlations between the surface flow and the creeping region in the case of steady and fully developed flows. We found that the height of the surface flow and the characteristic decay length of the creeping zone are linked through an affine relation which depends on the micromechanical parameters. Therefore the surface flow and the creeping zone are characterized by only one length. © 2015 Taylor & Francis Group.
Perry N.,Arts et Metiers ParisTech |
Bernard A.,École Centrale Nantes |
Laroche F.,École Centrale Nantes |
CIRP Annals - Manufacturing Technology | Year: 2012
The use of composite material increases. End of life regulations, material consumption reductions or restrictions, ask engineers about their potential use. Innovative recycling solutions arise that recover efficiently carbon fibres. This paper explores the design for composites recycling issue. Recycler becomes a new knowledge expert for the designer. It is necessary to analyze their information shares and exchanges. The recycler is an end of life facilitator. He is also the second life material user and can ask for material evolutions. The collaboration must be improved using knowledge performance indicators. These discussions will be enlightened by examples from carbon recycling experiments. © 2012 CIRP.
Durand-Estebe B.,I2M |
Lebot C.,I2M |
Arquis E.,I2M |
Mancos J.N.,Cap Ingelec
ASME 2012 11th Biennial Conference on Engineering Systems Design and Analysis, ESDA 2012 | Year: 2012
Air flow management in a Data-center is a critical problem when designing HVAC (Heating, Ventilation and AirConditioning) system. Providing a sufficient cooling air volume at a designed temperature to all the informatics equipments, avoiding recirculation phenomenon, optimizing the installations in order to minimize the temperature difference between air exiting the CRAC (Computer Room Air Conditioning) and the air at the intake of the servers are parts of the multiples target that have to be reached in order to have the most efficient ventilation system. In most of today's data center, the IT (Information Technology) equipment dissipates between 12kW of heat for regular material, to up to 32kW for the recent high density server's rack. Such a power release has to be cooled by efficient cooling system. During this process the airflow temperature can increase by over 10K, and the air velocity can vary from 0.09m/s to more than 5m/s. Considering these large gradient of temperature and air speed several phenomenon must be taken into account, including turbulent natural convection. To achieve these goals, we will use a CFD software to predict the airflow behaviour inside the Data-center. Therefore, the code must be able to accurately model turbulent airflow and heat transfers. We used the software (http/www.thetis.enscbp.fr) to simulate a 2D turbulent natural convection in a square cavity. The k-ε equations were solved to predict turbulent effects. The obtained results were compared to an experimental benchmark and are presented in the document. In the last part of the paper we present the results of a 2D simulation representing a working server in a computer room cooled by a CRAC (Computer Room Air Conditioning) unit. The airflow characteristics in the whole domain were determined using various dimensionless numbers in order to select the right physical and mathematical objects. Finally the results of a 3D simulation are presented and the cooling system performances are estimated. Copyright © 2012 by ASME.
ASME 2012 11th Biennial Conference on Engineering Systems Design and Analysis, ESDA 2012 | Year: 2012
Numerical simulations of composite structures are generally performed using multi-layered shell elements in the context of the finite elements method. This strategy has numerous advantages like a low computation time and the capability to reproduce the comportment of composites in most of cases. The main restriction of this approach is that it has only a coarse description of strain and stresses variations in the thickness. This approximation is no more valid when increasing the thickness, near the boundary and loading conditions and when non linear phenomena like delamination occurs in the thickness. This paper explores an alternative to shell computation using the Proper Generalized Methods based on a separated representation. The idea is to solve the full 3D solid problem separating the in-plane and the out-of-plane spaces. Practically, a classical shell mesh is used to describe the inplane geometry and a simple 1D mesh is used to deal with the out-of-plane space. This allows to represents complex fields in the thickness without the complexity and the computation cost of a solid mesh which is particularly interesting when dealing with multi-layer composite. Copyright © 2012 by ASME.
Hernando L.,I2M |
Omari A.,I2M |
Powder Technology | Year: 2014
The goal of this paper was to experimentally investigate sedimentation of concentrated suspensions of mono-sized particles at low Reynolds number. Experiments were carried out with polymethylmethacrylate (PMMA) spheres of three different radii suspended in a fluid of matched refraction index. Laser Induced Fluorescence technique was used to determine the spatio-temporal evolution of particle concentration and displacement of sedimentation fronts. It was mainly possible to recognize the existence of specific modes that govern the sedimentation process when particle radius is changed. As a consequence, the maximum packing concentration of the sediment was found to be a decreasing function of particle radius and observed results were found to be well correlated with the corresponding Richardson and Zaki flux function. © 2014 Elsevier B.V.
News Article | February 27, 2017
Investing in a backup planet might be a good idea, given what’s been happening on Earth lately. The cost would only be a little over $20 trillion, but some nice real estate just came on the market. The discovery of seven Earth-like planets orbiting a nearby star has really gotten everyone thinking about space colonization again. Found by NASA's orbiting Spitzer Space Telescope and the ground-based TRAPPIST Telescope, there seems to be at least seven Earth-sized planets orbiting the star TRAPPIST-1. The biggest surprise is that three or four of these planets are in the Goldilocks Zone - not too far from the star, not too close, not too big for a planet, not too small – a sweet spot where liquid water is stable on the right-sized planet with an atmosphere on which life could develop or survive if transplanted. All these planets are similar to several planets in our own Solar System, but the fourth planet out, TRAPPIST-1e, seems the most favorable for life. Suddenly, we are talking about intelligent life elsewhere in the Galaxy, and travelling through space to get there. Is this desirable? Is it even possible? In this case, nearby means just under 40 light years away, a mere 230 trillion miles. Such a journey would take only a few years at 99.9999% of the speed of light or about 600,000 years at the fastest speeds we’ve recently attained with some clever slingshots around big planets. So we just have to make a ship that can travel close to the speed of light. Over the years, many ideas have emerged to do that, mostly from nuclear fusion, like the Bussard Ramjet of Niven’s series that is powered by collecting interstellar hydrogen to fuse. Whatever method you chose, the absence of friction in space means you just have to give continuous pulses of thrust, even tiny ones, that eventually accumulate to push the vessel to near-light speeds. TRAPPIST-1 is a small M-type ultracool dwarf star that has a mass, luminosity and radius about a tenth those of our Sun. It has a surface temperature of 2,550 K (4,130°F) and is young, not much over 500 million years. Our Sun is G-type yellow star with a surface temperature of 5,778 K (9,941°F) that formed 4.5 billion years ago. TRAPPIST-1 is metal rich, meaning it formed from a gaseous nebula rich in metals accumulated from past supernovae. Supernovae are the only explosions large enough to form metals heavier than iron. The TRAPPIST-1 star is barely bigger than Jupiter, but the TRAPPIST-1 worlds are very much like some of the smaller planets in our own solar system, like Earth, Mars and the icy satellites of the outer Solar System. The Goldilocks Zone is essential to the origin of life on any planet. For life to develop, you need water as liquid (year-round), an atmosphere, carbon and a few common elements like sulfur and nitrogen, and some common energy sources like lightning, volcanic heat, ultraviolet radiation, ocean wave impact, or a few others. Carbon is essential since it is the only element that can bond with itself almost an infinite number of times to form increasingly complex compounds. Water is necessary since it is the only compound with the right boiling and freezing points, thermal and electrical conductivities, density of its solid with respect to its liquid, is the most effective solvent, has great acid-base properties, and forms hydrogen bonds, all properties necessary for life to develop. We know these things from many experiments that recreated early Earth conditions in the laboratory and formed the organic compounds needed to evolve into life. The most famous were performed by Stanley Miller in the 1950s and refined later by many researchers (including yours truly) after we learned more about the conditions that existed during the first billion years on Earth. The early Earth was not reducing but was anoxic from outgassing during continuous volcanism. So there was no free hydrogen but lots of carbon dioxide. If you take a sterile mixture of pure water, some gases like CO2, H2SO4, NH3, Cl and some sterile volcanic dirt (all components that come from erupting volcanoes on Earth), and spark some lightning through it, within only 2 days a slew of complex compounds form, turning the mixture into a veritable organic soup. Forty years ago, as a young planetary geologist with a specialty in extraterrestrial biology, my particular soup yielded simple sugars like glucose, various amino acids and polypeptides, lipids, oils and tars, complex sugars like ribose, and very complex purine and pyrimidine bases. All of which are the building blocks of cells and key components like ribonucleic acid. And all created by well-known chemical reactions that were later harnessed by reactive proteins called enzymes which would eventually become the biochemical engines of living cells. Of course, going from the building blocks to actual living organisms took another several hundred million years of slow chemical evolution. Not random, just slow. If it’s so easy to create the building blocks of life, then there should be plenty of life on the billions of planets that exist just in our own Galaxy. And there should be intelligent life on some of those, too, given sufficient time. Carl Sagan calculated this possibility about 40 years ago using the Drake equation. Conservatively, there are millions of planets in our Galaxy that have life, and thousands of planets that have intelligent life. However, if TRAPPIST-1 is only 500 million years old, then it is unlikely sufficient time has occurred for intelligent life to have developed on one of its planets. On the other hand, we might be able to terraform one of these planets. It took microbial life about 2 billion years to turn Earth’s anoxic atmosphere to one with free oxygen, but seeding the right planet with the right microbes could work much faster. So assuming there is life out there, can we reach it? Can it reach us? If we go fast enough, maybe. The speed of light really is the Universe’s speed limit. At 671 million miles/hour, it can only be achieved if you have no mass, like a wave of light. Subatomic particles can get close, but when something like humans in a spaceship approach the speed of light, things go weird. General Relativity tells us that interstellar space travel at near-light speeds also involves a bit of time travel as well, at least relative to the residents of Earth that would be left behind. As you approach light speed, time slows down, space contracts and your mass increases to infinity. But only relative to outside the ship. Inside the ship everything seems normal. Even the radiation dose to the crew would only be that of years, not decades. This effect even has an equation to describe it – the Lawrence Transformation Equations. If the ship is traveling at 99.9999% of the speed of light, it will take about 40 years in Earth time to get there, but only about 21 days will have passed on the ship! If there are people on board and the ship is limited to one G of acceleration, then the ship will take about 42 years to reach TRAPPIST-1 in Earth time and 7.2 years ship time (3.6 years to accelerate and 3.6 years to decelerate. (Note- thanks to Timothy Weaver who noticed my LTE calculations were backwards! Also see The Relativistic Rocket and I2M) This gets to the heart of investing in such a venture. There is no real return on the investment for individual investors. If a ship traveled to TRAPPIST-1, then came back, 80 years would have passed on Earth. Who would invest in this? Altruism for the future of the species just may not be enough. Also, that money might be better spent on fixing what’s wrong on Earth. On the other hand, it's not too different from oceanic exploration of 500 years ago when many explorers didn't expect to ever return home. But TRAPPIST-1 is rich in metals, which means the planets orbiting TRAPPIST-1 are also rich in metals, hundreds of times more so than Earth. So if Platinum Group Metals, Rare Earth Elements and Noble Metals like gold are of interest to you, boy, do I have a planet for you! Of course, the same issues exist with another civilization wanting to visit Earth. There certainly is life elsewhere in the Galaxy. But General Relativity says those things you're seeing are not UFOs, you’ve just been smoking too much. Dr. James Conca is a geochemist, an energy expert, an authority on dirty bombs, a planetary geologist and professional speaker. Follow him on Twitter @jimconca and see his book at Amazon.com