On sixfold coupled vibrations of thin-walled composite box beams

This paper presents a general analytical model for free vibration of thin-walled composite beams with arbitrary laminate stacking sequences and studies the effects of shear deformation over the natural frequencies. This model is based on the first-order shear-deformable beam theory and accounts for all the structural coupling coming from the material anisotropy. The seven governing differential equations for coupled flexural–torsional–shearing vibration are derived from the Hamilton’s principle. The resulting coupling is referred to as sixfold coupled vibration. Numerical results are obtained to investigate the effects of fiber angle, span-to-height ratio, modulus ratio, and boundary conditions on the natural frequencies as well as corresponding mode shapes of thin-walled composite box beams

New methods aiming to improve the performances of aircraft flight trajectory optimization algorithms

In this thesis, three investigations aimed to explore new ways for improving the performances and capabilities of the flight trajectory optimization algorithms used by the Flight Management System. The first investigation explored a new method of selecting the geographical area considered in the flight trajectory optimization, and the construction of a corresponding routing grid. The geographical area selection method ensured the separate control over the maximal trajectory distance between the departure and destination airports, and the size of the operational area around the airports. The performances of the proposed method were analyzed using flight data from three commercial flights corresponding to short and long-haul flights. The analysis showed that the grids constructed using the proposed method had a lower number of grid nodes than the rectangular grids covering the same maximal and minimal latitudes, and longitudes. Thus, an optimization algorithm would have to evaluate a smaller number of waypoints. The analysis also showed that the proposed method was more adapted for medium and long-haul flight trajectories than for short flight trajectories. The second investigation explored a new method for reducing the volume of recurring segment performance computations, and the execution times demanded by a flight trajectory optimization algorithm. The proposed method constructed a look-up structure, defining the still-air performance parameters of the ensemble of vertical flight path segments available for the construction of the optimal trajectory. It also constructed a corresponding graph which could be used for aiding in the selection of the vertical flight path segments. The look-up structure and graph construction used the same aircraft performance model and data as the FMS trajectory computation algorithms. The following limitations were imposed in the development of this method: 1) the set of segments defined one climb and multiple horizontal constant-speed cruise, climb-in-cruise, and descent flight paths connecting the Take-Off and the End Of Descent; 2) for each flight phase, the segments correspond to a consigned speed schedule, defined as a couple of Indicated Air Speed and Mach values, and a consigned air temperature; the cruise altitudes were limited by the imposed minimal value, and by the maximal value allowed by aircraft performances, at intervals of 1,000 ft; the number of descent paths was selected through the number of aircraft Gross Weights at the End Of Descent. A number of nine test scenarios were used to analyze the performances of the proposed method, such as: 1) the number of segments composing the look-up structure; 2) the number of graph nodes; 3) the number of possible vertical flight paths connecting the Take-Off to an End Of Descent; 4) the minimal and maximal flight time and distance values,and their corresponding vertical flight paths; 5) the distribution of the vertical flight paths’ flight time versus flight distance values; and 6) the execution times required to construct the look-up structures and graphs. The third investigation explored a new method used for the geometrical construction of an optimal vertical flight plan as a function of the lateral flight plan waypoints’ along-the-track distance from the initial waypoint, their altitude and gradient restrictions, and a set of preferred gradient values defined as a function of flight phase and altitude. The main advantage of the proposed method resides in its reduced complexity, and in its increased processing speed relative to the speed of the methods employing the aircraft performance model. A second advantage is the generation of a ground-fixed optimized vertical flight plan, not affected by changing wind conditions. Two implementations of the proposed method adopting different segments construction strategies for consecutive segments leading to conflicting gradient and horizontal segment length requirements were analyzed using 48 test scenarios

Altitude optimization algorithm for cruise, constant speed and level flight segments

In this thesis, the development of an algorithm is presented. The algorithm determines the optimal cruise altitude for flying an aircraft at a constant speed and altitude on a given segment of the flight route. The optimization criteria corresponds to the minimization of the total costs, and, if possible, fuel consumption, associated with flying the cruise segment. The main objective is the development of a new algorithm, for a functionality of the FMS platform, that will display for the pilots the advisory information on a segment’s cruise altitude yielding the minimal cost. The algorithm, developed in MATLAB, is using a new method for computing the fuel burn, for the level flight cruise segments, based on the aircraft’s performance data. Three aircraft models were considered, one whose cruise modeling uses the center of gravity position, and two that do not use the center of gravity position. The algorithm was developed for normal flight conditions, and does not consider the costs associated with the initial and final changes of altitude, necessary to reach the optimal altitude and, at the end of the segment, needed to return to the initial cruise altitude. Algorithm performances were evaluated on three aircraft models – Airbus A310, Sukhoi RRJ and Lockheed L1011. The validation data were generated based on the information produced on a CMC Electronics – Esterline FMS platform that used an identical aircraft model, and performance data, for identical flight conditions

Aircraft Trajectory Optimization for a Cruise Segment with Imposed Flight Time Constraint

The work presented in this thesis is applied in the field of aircraft flight trajectory optimization, approached as a flight-planning problem. The objective of the optimization is to determine an optimal flight plan, which minimizes a selected cost function and satisfies all the imposed constraints. The optimization takes into account the particular aircraft performance data and flight configuration (load, fuel quantity, etc.), initial and final points (latitudes, longitudes, and altitudes) of the flight segment to be optimized, atmospheric conditions along the flight trajectory, as well as optimization and navigation constraints. It was assumed in this work that the lateral component of a flight plan was composed by a set of sub-segments, constructed by selecting adjacent nodes from a routing grid. The routing grid was constructed based on the orthodromic route between the initial and final points of the segment to be optimized, a selected maximum lateral deviation from the orthodromic route, and a maximum sea level distance between the grid nodes. The first research subject concerned a new atmospheric data model that defines the variation of the atmospheric parameters as functions of time in selected points along the lateral flight trajectory or in the nodes of a routing grid, at a selected altitude. The model was constructed based on the forecast data provided by the Meteorological Agencies, in GRIB2 data format, and defined in the nodes of a 4D grid (geographic location, altitude, and time). As a result, an atmospheric parameter value in an atmospheric data definition point (geographic location and altitude), at the time instance of interest, was obtained by a one-dimensional linear interpolation. Test results showed that, compared with the classic four-dimensional linear interpolation from the GRIB forecast data, the proposed model yielded identical atmospheric parameters values (differences of the order of 10-14) and, on average, it was six times faster. Therefore, by using the proposed atmospheric data model it would be possible to perform an optimization faster or to evaluate more candidate flight plans during the allotted execution time, which would yield better optimization results. The proposed model can be extended by generating the model data for each altitude from a set of altitudes of interest. The second investigation evaluates the performance of a new optimization method, based on genetic algorithms, where both the lateral and the vertical components of the flight plan are subjected to optimization. In this study, the routing grid for the lateral component of the candidate flight plans was constructed according to the methodology presented in the first investigation. The family of vertical flight plans was constructed according to a selected structure and topology. The results were compared with a reference flight plan, obtained as the optimal profile (speed optimization) for a flight along the flight track and altitude profile of a real flight, retrieved from the FlightAware website. Subsequently, another investigation analyzed the effects of performing flight plan corrections (altitude – speed profile) relative to the aircraft flight envelope (correction of the candidate flight plan parameters, so that the aircraft flight parameters would remain within the flight envelope limits), on the optimization results and execution time. A total of 60 tests were performed, composed of 10 test runs for each of the six cost index values considered in the evaluation. The results showed that, by performing the flight plan corrections relative to the aircraft flight envelope, the computation times increase by a factor larger than two and the results are less optimal. Relative to the reference flight plan, the proposed optimization method, in which the candidate flight plans were not corrected, yielded a total cost reduction between 1.598% and 3.97%. The third investigation evaluates a new flight plan optimization method / approach, derived from the Non-dominated Sorting Genetic Algorithm II multi-objective optimization method. The proposed method applies to the case where a crossing time is desired / expected to be imposed at the final point of the segment under optimization (Required Time of Arrival). The time constraint value could be a preferred crossing time instance selected by the flight planner or, it could result from a negotiation with the Air Traffic Management System. The proposed method identifies, in parallel, a set of optimal flight plans corresponding to a set of selected contiguous flight time constraints (“windows”) imposed at the final point of the flight segment to be optimized. The advantage of the proposed method is that decision makers can select the flight plan that best suits their criteria and, if rejected by the Air Traffic Management system, they can select the next best flight plan from the set of solutions without having to perform a new optimization. Seven method variants were evaluated, and 10 test runs were performed for each variant. The tests considered the case where 31 contiguous time constraint windows were imposed at the final point of the segment under optimization. Test results showed a very good convergence of the solutions. For five method variants the maximum fuel burn differences relative to the “global” minimum for a time constraint value (for all the method variants and all the test runs) were less than 90 kg of fuel (0.14%). The worst optimization method found optimal flight plans that yielded fuel burns with a maximum of 321 kg (0.56%) more than the “global” optimum

Algorithme d'optimisation du profil vertical pour un segment de vol en croisière avec une contrainte d'heure d'arrivée requise

Ce mémoire présente le développement d'un algorithme qui détermine le profil optimal de navigation verticale (VNAV) pour un segment de vol en croisière, au long d'un profil donné de navigation latérale (LNAV), ayant une contrainte d'heure d'arrivée requise (RTA). L'algorithme est destiné à être implémenté dans un Système de Gestion de Vol (FMS) en tant que nouvelle fonctionnalité offrant des informations consultatives sur le profil optimal de VNAV. L'objectif de l'optimisation est la minimisation du coût total associé au vol sur le segment de croisière alors que l'heure d'arrivée à la fin du segment se trouve dans un intervalle de temps imposé. Pour les profils verticaux de navigation ayant l'heure d'arrivée dans les limites imposées le degré de réalisation de la contrainte de RTA est quantifié par un coût proportionnel à la valeur absolue de la différence entre l'heure d'arrivée réelle et la RTA. Les profils de VNAV évalués dans ce mémoire sont caractérisés par des altitudes identiques au début et à la fin du profil, ils contiennent au maximum un pas d'altitude relatif à l'altitude au point de début du profil et le vol est réalisé à une vitesse constante. Les segments d'accélération et de décélération ne sont pas pris en compte. Les gammes d'altitudes et de vitesses à utiliser pour les profils de VNAV sont fournies comme des paramètres à l'appel de l'algorithme. L'algorithme présenté dans ce mémoire est développé en MATLAB. À chaque altitude, dans la gamme d'altitudes à utiliser pour les profils de VNAV, une recherche binaire est effectué pour identifier le domaine de vitesses qui rendent une heure d'arrivée compatible avec la contrainte de RTA et le profil ayant le coût total minimal est retenu. Les paramétrés de performance qui déterminent le coût total pour le vol au long d'un profil de VNAV, la consommation de combustible et le temps de vol, sont calculés à partir des tableaux de performance et de la configuration de l'avion, de son profil de montée et de descente, de l'altitude initiale au début du profil VNAV, des profils de VNAV et de LNAV, et des conditions atmosphériques. Ces calculs ont été validés avec des données générées par une plate-forme FMS produite par CMC Electronics - Esterline pour un avion Airbus A310. Les performances de l'algorithme ont été évaluées avec deux modèles d'avion, l'Airbus A310 et le Sukhoi RRJ, trois profils de LNAV et trois profils de vents

Расчетно-статистические модели режимов потребления электроэнергии как основа нормирования и оценки энергетической эффективности

Необходимым прямым и косвенным инструментом государственной политики энергосбережения яв­ляется механизм нормирования расхода топлива и энергии для технических процессов, установок, продукции [1]. Нормирование потребления топливно-энергетических ресурсов (ТЭР), с одной сторо­ны, необходимо для определения энергетической составляющей затрат в структуре себестоимости продукции (при калькуляции себестоимости), а с другой стороны — для оценки эффективности использования ТЭР. Нормирование расхода ТЭР является одним из элементов экономической части по­литики энергосбережения, способствует устранению неэффективного использования ТЭР и внедре­нию энергосберегающих мероприятий, призвано регулировать деятельность промышленных потре­бителей в области энергосбережения

Инфекционные поражения половых путей у женщин репродуктивного возраста вирусом папилломы человека

МОЧЕПОЛОВЫЕ БОЛЕЗНИЖЕНСКИЕ БОЛЕЗНИПАПИЛЛОМАВИРУС ЧЕЛОВЕКАПАПИЛЛОМАВИРУСНЫЕ ИНФЕКЦИИДНК-ВИРУСНЫЕ ИНФЕКЦИИОНКОГЕННОВИРУСНЫЕ ИНФЕКЦИИРЕПРОДУКЦИ

Millimeter-wave emissivity as a metric for the non-contact diagnosis of human skin conditions.

A half-space electromagnetic model of human skin over the band 30-300 GHz was constructed and used to model radiometric emissivity. The model showed that the radiometric emissivity rose from 0.4 to 0.8 over this band, with emission being localized to a layer approximately one millimeter deep in the skin. Simulations of skin with differing water contents associated with psoriasis, eczema, malignancy, and thermal burn wounds indicated radiometry could be used as a non-contact technique to detect and monitor these conditions. The skin emissivity of a sample of 30 healthy volunteers, measured using a 95 GHz radiometer, was found to range from 0.2 to 0.7, and the experimental measurement uncertainty was ±0.002. Men on average were found to have an emissivity 0.046 higher than those of women, a measurement consistent with men having thicker skin than women. The regions of outer wrist and dorsal forearm, where skin is thicker, had emissivities 0.06-0.08 higher than the inner wrist and volar forearms where skin is generally thinner. Recommendations are made to develop a more sophisticated model of the skin and to collect larger data sets to obtain a deeper understanding of the signatures of human skin in the millimeter wave band. Bioelectromagnetics. 2017;9999:XX-XX. © 2017 The Authors. Bioelectromagnetics published by Wiley Periodicals, Inc