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MEIE2018 | Nader Asnafi
Nader Asnafi
Mechanical Engineering, Örebro University, Sweden

Speech Title: Selective Laser heat Treatment to Tailor the Autobody Part Properties and Improve the Manufacturing Flexibility
Abstract: This investigation is focused on the stamping behaviour of boron steel, the properties of which are modified by selective laser heat treatment. Both CO2 and fibre lasers are tested. By using different laser processing parameters, the hardening depth in the 1 mm thick boron steel sheet Boloc 02 is varied. Four routes are tested and verified. The forming operation (in which a so-called flexrail beam is produced) in all four routes is conducted at ambient (room) temperature. The Reference route comprises stamping of the sheet. The GridBlank route starts with selective laser heat treatment of the blank, after which the blank is allowed to cool down, moved to a hydraulic press and stamped. In the GridTube route, the blank is first stamped, after which the part is moved to a laser cell and selectively laser heat treated. The fourth route, the RapidLaser route, is similar to the GridBlank route, but a higher laser speed is used to promote higher total productivity. The GridBlank route results in the highest hardness values and the best shape accuracy. The initial sheet material exhibits a hardness of 200 HV, while the parts produced in the GridBlank route exhibit a hardness of 700 HV.
MEIE2018 | Nader Asnafi
Zheng Hong (George) Zhu
Professor and Chair
Department of Mechanical Engineering, York University, Canada

Speech Title:Dynamics and Control of Electrodynamic Tethers in Space Debris Removal with Consideration of Elastic-Thermal-Electrical Coupling Effects
Abstract: Electrodynamic Tether (EDT) system is a noval spacecraft that is formed by connecting two satellites with a conductive tether. It possesses unique capabilities to lower or boost spacecraft orbits, power generation, and deorbit space debris, without consuming propellant. The EDT technology takes advantage of two fundamental principles of electromagnetism: electrical current is produced when a conductive wire moves through a magnetic field, and the field exerts a force on the current carrying wire. One of the most appealing application of EDT is the space debris removal due to the advantages of propellentless, low mass, compact size, ease of use and low cost. This paper investigates the elastic, thermal, and electrical coupling effects on the dynamics and libration stability of flexible bare electrodynamic tethers in the space debris deorbit. A high fidelity model is developed by considering transverse and longitudinal dynamics and libration dynamics of the tether and environmental effects with the latest models for atmospheric and plasma density, and Earth gravity and magnetic fields. The long-term orbital and libration dynamics of tether are analyzed by a nodal position finite element method and Symplectic time integration. Two practical and effective electrical current on/off control strategies are developed based on the libration energy and libration angles. Although the libration energy control is found to be more stable and efficient than the libration angle control, the latter is more appealing for practical applications due to its simplicity and low computational effort.
MEIE2018 | Nader Asnafi
Mechanical Engineering, Ecole Centrale de Lyon (ECL), France

Speech Title: Vibroacoustics of Periodic Media - VIPER
Abstract: VIPER is a European Joint Doctorate on Vibroacoustics. VIPER aims at consolidating academic research dealing with VIbroacoustics of PERiodic media. Structural periodic design is a powerful strategy for lightweight structures achievements while remaining a convenient solution for manufacturing guidelines aspects. Including vibroacoustic design rules at early stage of products development is one of the main research targets. Periodic media exhibit proper dynamic filtering effects that can be smartly used for vibroacoustic design. The question addressed then is simple: how periodic concepts can improve the broadband vibroacoustic signatures and performances? Most of vibroacoustic treatments are frequency band limited. Indeed, on the one hand, viscoelastic materials (for instance) can be used for low frequency passive vibration control. On the other hand, poroelastic blankets are efficient for high and mid frequency absorption of acoustic disturbance. Newly and extensively employed lightweight structures present a strong dynamical overlapping between low, mid and high frequency bands that needs to be dealt with.

The VIPER project’s main goal is to develop and to validate tools for the design of global vibroacoustic treatments based on periodic patterns allowing passive control of vibration and acoustic paths in layered concepts. This will be achieved by addressing in-depth structural periodicity stiffness as well as absorption attributes. The proposed concepts would ensure a significant improvement of vibroacoustic performances in a wide frequency range. Dealing with large scale periodic structural-acoustic concepts involves a multi-scale aspect that needs specific numerical tools. A two scale strategy will be pursued in most of the achievements to handle periodicity effects: the meso-scale is related to the elementary cell or the span, while the macroscale relates to the full-size structure. Each scale will be characterized by its own efficiency indicators: effective parameters (mechanical and acoustical equivalent material properties, dispersion characteristics…) at the meso-scale, and vibroacoustic indicators (structural damping, acoustic absorption, transmission loss…) at the macro-scale.
MEIE2018 | Nader Asnafi
Thomas Yang
Electrical and Computer Engineering, Embry-Riddle Aeronautical University, USA

Speech Title: Consensus of Multi-agent Systems via Efficient Cooperative Control with Applications in Formation Control for Autonomous Systems
Abstract: Discontinuous cooperative control protocols are proposed for the consensus of multi-agent systems with directed and switching sensing (communication) topologies and time delays. By introducing a new design for nonlinear cooperative control gains, multi-agent system consensus can be guaranteed in the presence of switching topologies and time delays. Simulation and hardware experimental results for robot formation control applications will be presented.

MEIE2018 | Nader Asnafi
Liran Ma
Associate Professor
State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, China

Speech Title: Molecular behaviors in thin lubrication film
Abstract:Molecules confined in a nano gap always present special properties that are different from those at the macro scale. As a branch of nanotribology, thin film lubrication (TFL) exhibits unique phenomena and obeys specific lubrication rules that cannot be predicted by classical lubrication theory. The set-up of TFL theory and related models outlined a whole map for lubrication regimes while offering insight into the molecular pattern in a confined liquid film. However, to date, experiments are unlikely to observe and further confirm the TFL model owing to the great difficulties in extracting interfacial molecular information from bulk liquid nano-films in an actual fluidic/lubrication process. Here, we successfully distinguished the molecular information from the adsorbed layer and fluidic layer using a nano-sandwich structured film observed during the lubrication.
MEIE2018 | Nader Asnafi
Chun Kit Kwong
Associate Professor
Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, China

Speech Title: Modeling of customer preference for facilitating integrated product design
Abstract:Integrated product design is about the study of performing product design with consideration of various product lifecycle issues. In the past several decades, quite a number of research works were conducted to develop methodologies, techniques, tools and methods that can help design engineers consider assembly, manufacturability, environmental impact, quality, and cost issues in product design. In the early stage of product design, design specifications of new products need to be determined and some business and marketing issues such as profits, contract design and market share are commonly considered. However, thus far, not much research has attempted to take those issues into account while defining design specifications of new products. One of the key issues of incorporating business and marketing issues into the early product design stage is the modeling of customer preference. In this speech, a framework of incorporating business and marketing consideration into the early product design stage based on customer preference models is introduced. Research issues and challenges of customer preference modeling and integrated product design are presented.
MEIE2018 | Nader Asnafi
Ali Arefi
Senior Lecturer
Electrical Engineering, Murdoch University, Australia

Speech Title: Electric grid planning considering a peer-to-peer market
Abstract:The growth in technology and decline in installation cost of renewable generators and storage devices, e.g. PV rooftops and batteries, along with other smart home management devices has provided the chance for customers to change their electricity practices and try to manage their energy needs by generation or storage of electricity. As a matter of fact, the idea of passive energy consumers is currently converting to prosumers-era. Despite the potential benefits of PV/battery uptake among customers, the operation of both market and distribution network have faced with many challenges. In particular, the price of electricity has doubled over the last 8 years in Australia. This issue can be addressed by introducing the Peer-to-peer (P2P) trading energy as a proper incentive mechanism that encourages customers to stay on-grid to sell their energy surplus or compensate their generation shortage. In this presentation, a discussion is delivered on how P2P can be modelled in a long-term planning, how a planning formulation is established considering P2P market, and how to integrate operational and investment costs in the network planning. The results include the effect of P2P on the cost of utility and consumers and also the optimum plan strategy for both of them including investment on PV/battery or pole and wire.