Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

Pressure adaptive honeycomb: A new adaptive structure for aerospace applications

A new type of adaptive structure is presented that relies on pressurized honeycomb cells that extent a significant length with respect to the plane of the hexagons. By varying the pressure inside each of the cells, the stiffness can be altered. A variable stiffness in combination with an externally applied force field results in a fully embedded pressure adaptive actuator that can yield strains well beyond the state-of-the-art in adaptive materials. The stiffness change as a function of the pressure is modeled by assigning an equivalent material stiffness to the honeycomb walls that accounts for both the inherent material stiffness as the pressure-induced stiffness. A finite element analysis of a beam structure that relies on this model is shown to correlate well to experimental results of a three-point bend test. To demonstrate the concept of embedded pressure adaptive honeycomb, an wind tunnel test article with adaptive flap has been constructed and tested in a low speed wind tunnel. It has been proven that by varying the cell pressure the flap changed its geometry and subsequently altered the lift coefficient.Aerospace Structures & Design MethodologyAerospace Engineerin

Buckled precompressed elements: A new class of control actuators for subscale UAVs

This thesis presents the use of a new class of flight control actuators employing Post-Buckled Precompressed (PBP) piezoelectric elements in morphing wing Uninhabited Aerial Vehicles (UAVs). The new actuator relies on axial compression to amplify deflections and control forces simultaneously. Two designs employing morphing wing panels based on PBP actuators were conceived. One design relied on a change in curvature of the actuators to control the camber of the airfoil. Axial compression of the actuators was ensured by means of rubber bands and increased end rotation levels with almost a factor of two up to +/- 13.6deg peak-to-peak, with excellent correlation between theory and experiment. Wind tunnel tests quantitatively proved that wing morphing induced roll acceleration levels in excess of 1500deg/sˆ2. A second design employed PBP actuators in a wing panel with significant thickness, relying on a highly compliant Latex skin to allow for shape deformation and at the same time induce an axial force on the actuators. Bench tests showed that due to the axial compression provided by the skin end rotations were increased with more than a factor of two up to +/- 15.8deg peak-to-peak up to a break frequency of 34Hz. Compared to conventional electromechanical servoactuaters, the PBP actuators showed a net reduction in flight control system weight, slop and power consumption for minimal part count. Both morphing wing concepts showed that PBP piezoelectric actuators have significant benefits over conventional actuators and can be successfully applied to induce aircraft control.Aerospace Engineerin

Una reunión educativa con el bambu (An educational meeting with Bamboo)

The thesis is a research driven design study of a multiple floor/"high-rise" building with a structure of Laminated Guadua bamboo in Guayaquil Ecuador. Dealing with earthquakes, context, structure and sustainability issues. The Thesis is strongly oriented to structure, the industry and the state of the industry itself but always driven by sustainable consequences. It tried to explore the possibilities and the limitations of the context and the material itself. Results of the research and the design have also been tested regarding most aspects of sustainability and physical tests have been made to verify the claims, although no decisive conclusion can be made.Sustainable Design Graduation ProjectArchitectural Engineering and TechnologyArchitecture and The Built Environmen

Airplane adaptive structures; a passed station or a promise yet to be fulfilled?

Aerospace Engineerin

Post-buckled precompressed (PBP) subsonic micro flight control actuators and surfaces

This paper describes a new class of flight control actuators using Post-Buckled Precompressed (PBP) piezoelectric elements to provide much improved actuator performance. These PBP actuator elements are modeled using basic large deflection Euler-beam estimations accounting for laminated plate effects. The deflection estimations are then coupled to a high rotation kinematic model which translates PBP beam bending to stabilator deflections. A test article using PZT-5H piezoceramic sheets built into an active bender element was fitted with an elastic band which induced much improved deflection levels. Statically the bender element was capable of producing unloaded end rotations on the order of ±2.6°. With axial compression, the end deflections were shown to increase nearly 4-fold. The PBP element was then fitted with a graphite-epoxy aeroshell which was designed to pitch around a tubular stainless steel main spar. Quasi-static bench testing showed excellent correlation between theory and experiment through ±25° of pitch deflection. Finally, wind tunnel testing was conducted at airspeeds up to 120kts (62m/s, 202ft/s). Testing showed that deflections up through ±20° could be maintained at even the highest flight speed. The stabilator showed no flutter or divergence tendencies at all flight speeds. At higher deflection levels, it was shown that a slight degradation deflection was induced by nose-down pitching moments generated by separated flow conditions induced by extremely high angles of attack.Aerospace StructuresAerospace Engineerin

Topology optimization of pressure adaptive honeycomb for a morphing flap

The paper begins with a brief historical overview of pressure adaptive materials and structures. By examining avian anatomy, it is seen that pressure-adaptive structures have been used successfully in the Natural world to hold structural positions for extended periods of time and yet allow for dynamic shape changes from one flight state to the next. More modern pneumatic actuators, including FAA certified autopilot servoactuators are frequently used by aircraft around the world. Pneumatic artificial muscles (PAM) show good promise as aircraft actuators, but follow the traditional model of load concentration and distribution commonly found in aircraft. A new system is proposed which leaves distributed loads distributed and manipulates structures through a distributed actuator. By using Pressure Adaptive Honeycomb (PAH), it is shown that large structural deformations in excess of 50% strains can be achieved while maintaining full structural integrity and enabling secondary flight control mechanisms like flaps. The successful implementation of pressure-adaptive honeycomb in the trailing edge of a wing section sparked the motivation for subsequent research into the optimal topology of the pressure adaptive honeycomb within the trailing edge of a morphing flap. As an input for the optimization two known shapes are required: a desired shape in cruise configuration and a desired shape in landing configuration. In addition, the boundary conditions and load cases (including aerodynamic loads and internal pressure loads) should be specified for each condition. Finally, a set of six design variables is specified relating to the honeycomb and upper skin topology of the morphing flap. A finite-element model of the pressure-adaptive honeycomb structure is developed specifically tailored to generate fast but reliable results for a given combination of external loading, input variables, and boundary conditions. Based on two bench tests it is shown that this model correlates well to experimental results. The optimization process finds the skin and honeycomb topology that minimizes the error between the acquired shape and the desired shape in each configurationAerospace Structures and Design MethodologyAerospace Engineerin

Simulatie scheepvaart IJmond

Het IJmond- gebied omvat de haven van Amsterdam, het Noordzeekanaal en de sluizen van IJmuiden. De probleemstelling richt zich op de planningsmethodiek voor de afwikkeling van de scheepvaart in dit gebied. Het afstudeerproject (in opdracht van DGSM) betreft het ontwikkelen van een simulatiemodel waarin de gehanteerde planningsmethodiek opgenomen is. Dit betekent dat het model het gehele IJmond- gebied moet omvatten. Dit model dient als hulpmiddel bij het optimaliseren van de planning en om de gevolgen van toekomstige veranderingen in het systeem te onderzoeken. Het model is ontwikkeld in de simulatietaal Prosim. Naast de beschrijving van het scheepsproces, zijn facetten als de kolkvulling, de beschikbaarheid van sleepboten, de invloed van het weer en de planningsstrategie opgenomen. Met het model zijn de volgende simulaties uitgevoerd: - de invloed van de maximale tijd dat er gewacht wordt met schutten op aankomende schepen: er is onderzocht wat de gevolgen zijn voor de gemiddelde passeertijd van de schepen. - de invloed van de spreiding van onderhoudsperioden van de grootste sluis op de passeertijden van de schepen. - de gevolgen van de groei van het verkeersvolume van bepaalde scheepstypen op de wachten passeertijden. Na de verifikatie van het model kan geconcludeerd worden dat het model goed aan de doelstelling beantwoordt. Naast de wachttijden geeft het model inzicht in de passeertijden, de sluisbezetting, enz. De uitgevoerde simulaties geven duidelijke overeenkomsten met de werkelijkheid.Hydraulic EngineeringCivil Engineering and Geoscience

Formalizing Technology Descriptions for Selection During Conceptual Design

Evaluation and assessment of novel technologies for aerospace applications is essential for business strategy and decision making regarding development efforts. However, technology evaluation and assessment are challenging to perform objectively using a structured approach. As a first step towards a more objective and structured approach a graph-based description of engineering systems is described herein. Analyses can be applied to such a description through pattern matching, after which the quantities of interest can be computed by an automated algorithm using a dependency graph. The approach is applied to a simplified aircraft model, to perform a mission analysis and compute fuel burn. It is shown the method successfully computes the required parameter and is easily adapted to analyze an electric aircraft as well.Accepted Author Manuscript “New title: Formalizing Technology Descriptions for Selection During Conceptual Design”Flight Performance and Propulsio

Design aspects of integrated navigation for an unmanned Ballistocraft for Acceleration Research

For scientific experiments it is sometimes desirable to eliminate the earth gravity partially or entirely. It is possible to create this 'microgravity' with the use of a droptower, a spacevehicle or an aeroplane. Because the existing facilities for this kind of research are very expensive, have long waiting periods (space vehicle, aeroplane) or provide very short duration of microgravity (droptower), there is a need for a new system. Using an Unmanned AirVehicle (UAV) it is possible to solve the larger part of the problems mentioned before. This vehicle should be cheap, with a high availability and should be able to fly parabolic trajectories to create the microgravity. The UAV combines the relatively long duration of the microgravity in an aeroplane with the cheap and easy availability that is obtained in a drop tower…Applied SciencesElectrical EngineeringTelecommunications and Traffic Control Systems Grou