Luc Blecha

HEIG-VD | HEIG-VD · Department of Industrial Technologies (TIN)

Context. Measurements of the occultation of an exoplanet at visible wavelengths allow us to determine the reflective properties of a planetary atmosphere. The observed occultation depth can be translated into a geometric albedo. This in turn aids in characterising the structure and composition of an atmosphere by providing additional information on...

To foster the competitiveness of the European industry in the global launcher market, the need arose to build up the neces- sary know-how on state-of-the-art vertical take-off vertical landing (VTVL) concepts and corresponding technologies. In the EU Horizon 2020 project RETALT (RETro propulsion Assisted Landing Technologies), the VTVL approach ap...

To foster the competitiveness of the European industry in the global launcher market, the need arose to build up the necessary know-how on state-of-the-art vertical take-off vertical landing (VTVL) concepts and corresponding technologies. In the EU Horizon 2020 project RETALT (RETro propulsion Assisted Landing Technologies), the VTVL approach apply...

The development of the smallSats industry and the novel variety of on-boards instruments lead more and more to a miniaturisation of the space mechanisms. In addition to the smaller size, the reduction of the cost and the time to the market became primary objectives for recurring components used in space systems. With this variety of new application...

Flexible pivots present numerous advantages such as no wear, no particle generation and predictive torque. In addition, the patented design presented in this paper adds high stiffness tunability, large angle, nearly constant radial stiffness over the entire range of motion and infinite life capability. A design optimization software has been develo...

In 2014, Almatech has invented and patented a new family of flexible pivots for very large angular deflections in combination with infinite life and zero geometrical centershift. This novel pivot design concept has been selected by ESA for the development of a flexible hinge capable of infinite life rotations with a range of motion higher than ±70°...

Pyrovalves, i.e., valves actuated by a pyrotechnical device, are very often used in space propulsion systems for their fast response, high reliability, low mass and low cost. However, they are hazardous and single use items. Their operation induces shocks and can generate contaminants. If a slower actuation is required or possible, shape memory-bas...

The STIX (Spectrometer/Telescope for Imaging X-rays) instrument on the ESA Solar Orbiter satellite is designed to study the Sunrays emissions. The wide energy range of incident X-ray fluxes, expected during the solar flares, requires the incorporation of a moveable X-ray attenuator covering and uncovering the instrument detectors depending on X-ray...

SPICE is a high resolution imaging spectrometer operating at extreme ultraviolet wavelengths, 70.4 - 79.0 nm and 97.3 - 104.9 nm. It is a facility instrument on the Solar Orbiter mission. SPICE will address the key science goals of Solar Orbiter by providing the quantitative knowledge of the physical state and composition of the plasmas in the sola...

The STEAMR instrument is a Swedish national contribution to the ESA PREMIER mission, which is a candidate for the upcoming Earth Core Explorer mission. The STEAMR instrument is envisaged as a multi-beam limb sounding satellite, which will utilise 14 simultaneously observing beams in two 12 GHz wide bands from 323 to 357 GHz. To maximize spatial sam...

This article presents a novel method to compute in an efficient way, the coupled fluid-structure non-linear behaviour of hydrofoil sailing yacht. A parametric model of the pressure exerted by the fluid on the hydrofoil is determined from steady state 3D fluid simulation taking into account free surface and cavitation. The fluid pressure is applied...

In 2009, l’Hydroptère broke the symbolic barrier of 50 knots and became the world fastest sailing boat over both 500 meters and 1 nautical mile. This major achievement relied on the high skills of the sailing team but also on technical advances of the boat, resulting from the scientific collaboration between the Hydroptère Design Team and the Ecole...

In 2009, l’Hydroptère broke the symbolic barrier of 50 knots and became the world fastest sailing boat over both 500 meters and 1 nautical mile. This major achievement relied on the high skills of the sailing team but also on technical advances of the boat, resulting from long years of studies and development. This achievement is also an open windo...

An analytical model of the fluid/cell mechanical interaction was developed. The interfacial shear stress, due to the coupling between the fluid and the cell deformation, was characterized by a new dimensionless number N(fs). For N(fs) above a critical value, the fluid/cell interaction had a damping effect on the interfacial shear stress. Conversely...

Our goal was to develop a method to identify the optimal elastic modulus, Poisson's ratio, porosity, and permeability values for a mechanically stressed bone substitute. We hypothesized that a porous bone substitute that favors the transport of nutriments, wastes, biochemical signals, and cells, while keeping the fluid-induced shear stress within a...

The goal of this study was to develop a method that identifies optimal elastic modulus, Poisson’s ratio, porosity and permeability values for mechanically stressed bone substitute. It was hypothesized that porous bone substitute that favors the transport of nutriments, wastes, biochemical signals and cells while keeping the fluid-induced shear stre...

Synthetic bone substitutes are potentially the future gold standard in orthopaedic and traumatologic surgery. The availability of these bone substitutes with different biomechanical properties may well replace autografts in the future as they overcome complications associated with the graft harvesting procedure. In addition, bone substitutes have t...

A numerical model of the medial open wedge tibial osteotomy based on the finite element method was developed. Two plate positions were tested numerically. In a configuration, (a), the plate was fixed in a medial position and (b) in an anteromedial position. The simulation took into account soft tissues preload, muscular tonus and maximal gait load....