Evaluating GOCE data near a mid-ocean ridge and possible application to crustal structure in Scandinavia

GOCE gravity fields are assessed in an area around Reykjanes Ridge. Ship gravity measurements were found to be to inaccurate to determine possible improvement of GOCE gravity field models compared to the best available GRACE gravity field model. Differences between the GOCE gravity field models and EGM2008 does not appear to contain a component...

Multidisciplinary Design and Optimization Framework for Aircraft Box Structures

Competitive aircraft box structures are a perfect compromise between weight and price. The conceptual design process of these structures is a typical Multidisciplinary Design and Optimization effort, normally conducted by human engineers. The iterative nature of MDO turns development into a long and costly process. Knowledge-Based Engineering...

Buckling Analysis of Grid-Stiffened Composite Shells

There is a renewed interest in grid-stiffened composite structures; they are not only competitive with conventional stiffened constructions and sandwich shells in terms of weight but also enjoy superior damage tolerance properties. In this paper, both global and local structural instabilities are investigated for grid-stiffened composite panels...

Buckling optimization of steering stiffeners for grid-stiffened composite structures

Grid-stiffened composite structures, where the skin is stiffened by a lattice of stiffeners, not only allow for significant reduction in structural weight but are also competitive in terms of structural stability and damage tolerance compared with sandwich composite structures. As the development of Automated Fiber Placement (AFP) technology...

Isogeometric Shape Optimization for Quasi-static and Transient Problems

The recently developed isogeometric analysis (IGA) was aimed, from the start, at integrating computer aided design (CAD) and analysis. This synthesis of geometry and analysis has naturally led to renewed interest in developing structural shape optimization. The advantages of using isogeometric analysis in shape optimization are embodied in its...

Global-local Knowledge Coupling Approach to Support Airframe Structural Design

The outsourcing that has taken place in the aircraft industry over the last few decades has created a globalized supply chain from and to a limited number of original equipment manufacturers (OEMs). This has led to multi-level design due to the shift from airframe subsystem design to suppliers. Increasingly OEMs focus on requirement allocation...

Design and numerical investigation of swirl recovery vanes for the Fokker 29 propeller

Swirl recovery vanes (SRVs) are a set of stationary vanes located downstream from a propeller, which may recover some of the residual swirl from the propeller, hoping for an improvement in both thrust and efficiency. The SRV concept design for a scaled version representing the Fokker 29 propeller is performed in this paper, which may give rise...

Observations and analysis of phase scintillation of spacecraft signal on the interplanetary plasma

Aims. The phase scintillation of the European Space Agency’s Venus Express (VEX) spacecraft telemetry signal was observed at X-band (? = 3.6 cm) with a number of radio telescopes of the European Very Long Baseline Interferometry (VLBI) Network in the period 2009–2013. Methods. We found a phase fluctuation spectrum along the Venus orbit with a...

Tuning the stress induced martensitic formation in titanium alloys by alloy design

Dielectric behavior and phase transition in perovskite oxide Pb(Fe1/2Nb1/2)1?xTixO3 single crystal

Perovskite oxide Pb(Fe1/2Nb1/2)0.52Ti0.48O3 crystals, which were grown using a modified Bridgman method, show a high low-frequency dielectric constant response at room temperature. The Curie phase transition occurs at 523 K. The characteristic frequency of the dielectric dispersion versus the inverse of temperature obeys an Arrhenius relation,...

Separation of Ground and Low Vegetation Signatures in LiDAR Measurements of Salt-Marsh Environments

Light detection and ranging (LiDAR) has been shown to have a great potential in the accurate characterization of forest systems; however, its application to salt-marsh environments is challenging because the characteristic short vegetation does not give rise to detectable differences between first and last LiDAR returns. Furthermore, the lack of...

Embodied airflow sensing for improved in-gust flight of flapping wing MAVs

Flapping wing micro aerial vehicles (FWMAVs) are known for their flight agility and maneuverability. These bio-inspired and lightweight flying robots still present limitations in their ability to fly in direct wind and gusts, as their stability is severely compromised in contrast with their biological counterparts. To this end, this work aims at...

Stochastic Collocation with CFD robustness concepts for multi-dimensional stochastic space: Application to a transonic airfoil

Computational simulations have developed to a phase where the inherent physical variability prevalent in computational models exerts a larger effect on the predictive results than the deterministic numerical errors. To aim for more accurate and realistic simulations of the physical systems, it is imperative to include the input uncertainties...

Use of Anionic Polyamide-6 Composites in Oil and Gas Pipeline Environment