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Validation of VSPAERO for Basic Wing Simulation
Get PDFPotential flow theory-based numerical solvers have gained popularity for rapid and straightforward aerodynamic modeling across various applications, particularly in the early stages of design and in resource-limited projects such as small unmanned aerial vehicles (UAVs). These solvers offer a cost-effective solution for analyzing aerodynamic performance, and several well-established methods have demonstrated strong alignment with experimental data. Among these solvers is VSPAERO, a relatively recent addition integrated within the National Aeronautics and Space Administration’s (NASA) OpenVSP aircraft design software. Despite its growing use, a comprehensive validation of the VSPAERO solver remains necessary to ensure its reliability in diverse scenarios. This article presents a validation of the VSPAERO solver by conducting a series of case studies. The assessment includes comparisons against reference values obtained through empirical relationships, results from other established aerodynamic solvers and experimental data from wind tunnel testing. The assessment covers a range of geometries and flow conditions, highlighting areas where the solver performs well and identifying any limitations in its application. The findings provide insights into the meshing parameters required for accurate simulations, as well as the types of geometries and flow conditions for which VSPAERO can be considered a reliable tool. As a conclusion, the article presents a series of best practices and guidelines that are recommended to improve the accuracy and efficiency of future erodynamic simulations conducted using this software. These recommendations are intended to serve as a valuable reference for both researchers and engineers involved in aerodynamic modeling, particularly those working on projects with tight budgets or in the preliminary stages of aircraft design
A novel Digital Twin-based Structural Health Monitoring solution for offshore wind turbine platforms
Get PDFThis work introduces an innovative Structural Health Monitoring (SHM) solution for offshore wind platforms, featuring an advanced Digital Twin (DT) built on a fully-coupled aero-servo-hydro-elastic model. Our approach utilizes a detailed Finite Element model of the structure, meeting the requirements of the main assessment/certification standards. The application of the unique Enriched Modal Matrix Reduction technique leads substantially reduces CPU time, enabling near real-time calculations without compromising accuracy compared to the original FE model.
The SHM system is completed with an optimized sensors setup to monitor the most relevant deformation modes. Additionally, it enables precise fine-tuning of the DT model using machine learning, resulting in an accurate Hybrid Analysis Model.
Our modular and flexible DT-based SHM solution can be customized for any offshore wind platform concept, covering substructure, towers, mooring, and umbilicals. The solution is demonstrated through sea trials on Enerocean’s W2Power prototype
Autonomous Monitoring of Breathing Debonds in Composite Structures Using Non-Linear Ultrasonic Signals
Get PDFRobust adaptive fault tolerant control for nonlinear systems with actuator failure and mismatched disturbance
No full textIn this paper, a class of nonlinear system with mismatched disturbance and actuator failure is investigated. A disturbance observer is proposed to estimate the disturbance first and the error of the estimation converges to zero exponentially. By introducing an integral sliding mode surface, the disturbance observer based integral sliding mode fault tolerant control scheme is proposed to attenuate the disturbance and to guarantee the stability of the system. Specially, the control law is designed for decoupling the partial disturbance and attenuating the disturbance that cannot be decoupled. Finally, two examples are given to illustrate the effectiveness of the proposed method. Index Terms—Actuator fault, Fault tolerant control (FTC), Disturbance observer, Adaptive Integral Sliding mode control, Nonlinear system
Solvolysis of carbon fibre reinforced composites under mild conditions
No full textCarbon fibre reinforced composites (CFRP) are key in different industrial sectors as they combine lightness and robustness. This circumstance and the growing need to take advantage of the resources of any product, has triggered a strong demand to establish sustainable technological solutions that allow the effective use of composite materials: resins (matrix) and fibres (reinforcement).
Limited to mechanical recycling, recycling alternatives for CFRP with thermosetting resins have focused on thermochemical treatments, usually pyrolysis to recover the fibres, degrading the matrix. In addition to thermal routes, solvent treatments under supercritical conditions have also been studied. However, these processes exclude resin recovery and involve a partial loss of mechanical properties of the fibres due to the heat treatment (450-550 °C).
As an alternative, a solvolysis using mild conditions is proposed to treat CFRPs with amine-hardened epoxy resins, so that the fibres are recovered with all their properties and the organic matrix is materially valorised. This process is applied to reference materials of known composition and validated with real residues with good results in terms of degree of resin decomposition. The recovered fibres show almost resin-free surface and seem to have mechanical properties comparable to those of virgin fibres
The Twin Towers Collapse, Event Analyses and Structural Lessons, Master's Degree Thesis
No full textThis thesis is divided into two parts: in the first part the collapse of the WTC1, WTC 2 (Twin Towers) and WTC 7 buildings following the terrorist attacks of 11 September 2001 is analysed. In the second part, the collapse type and strength of frame buildings with different topological characteristics. What links the two parts is structural robustness.
Below is an overview of the work with a description of the topic covered in each Chapter.
Chapter 1: description of the structural and fire protection characteristics of the WTC 1, WTC 2 and WTC 7 buildings.
Chapter 2: timeline of the terrorist events of September 11, 2001.
Chapter 3: description of the types of fire, the performance of structures and the behavior of the main building materials (steel, concrete) to fire.
Chapter 4: analysis of the main hypotheses of the collapse of the Twin Towers present in the literature.
Chapter 5: definition of structural robustness, structural toughness, vulnerability. Description of project strategies to prevent progressive collapses.
Chapter 6: measurement of the structural strength of buildings with a reinforced concrete frame structure. through Discrete Element simulations (DEM).
Chapter 7: discussion of progressive collapse due to impacts from an analytical and bibliographical point of view
Construction Project Management & Green Building
Get PDFThis thesis studied the definition of a green building and the elements associated with the
construction of sustainability. There are many rating systems available across the country
both private and public. The most well-known is the LEED rating system developed by the
United States Green Building Council. LEED has several rating programs now available. In
this thesis, I will discuss why Green Building is more significant than conventional building
and methods of Green Building like construction Phases. Conventional buildings produce
high amounts of greenhouse gas, a large quantity of construction and demolition debris
(which decrease landfill capacity), disturb natural resources, and consume much energy and
water. Implementation of various simple and sustainable techniques practiced individually
can help in many ways to create an environmentally friendly structure, consume minimal
natural resources and at the same time be economical. This paper tries to study the Green
Building construction method and innovative technologies that enable us to create a
sustainable structure. It also includes design concepts of Green Building, methodology and
materials requirements, and ideas and suggestions to create a checklist for a builder to
refer to the various suggestions in every phase of construction of a general structure
4t. Congrés d’Economia i Empresa
No full textControl de les polítiques públiques i qualitat institucional
Anna Tarrach Colls
Sindica de la Sindicatura de Comptes de Catalunya
Abstract
Les administracions públiques s'enfronten a una sèrie de reptes de gran transcendència per al futur: demogràfics, socials, econòmics, mediambientals, sanitaris i tecnològics. Aquests desafiaments s’encaren en un context de retorn de les regles fiscals en l’àmbit de la Unió Europea i de desconfiança creixent en les institucions públiques i en l'ús que fan dels recursos públics.
La qualitat democràtica d’un país es mesura, d’entre altres elements, per la bona administració dels recursos públics. Entenem per “bona administració” fer bé les coses correctes. Aquest és el concepte d’efectivitat, és a dir fer les coses de forma eficaç i eficient.
Tenir una bona administració dels recursos públics és un deure per les administracions públiques i un dret dels ciutadans i aquests deures i drets poden estar condicionats per l’estructura institucional d’un país en la mesura en què faciliti o no la transparència i el retiment de comptes.
Hi ha diferents nivells de control sobre els recursos públics. El primer control és el que exerceixen els propis impulsors o gestors de les intervencions públiques. Aquests han de vetllar perquè les iniciatives que es financen amb fons públics siguin les més òptimes. Això implica que les noves intervencions s’haurien d’avaluar ex ante en termes de costos i beneficis econòmics i socials i que se n’hauria de fer un seguiment i una avaluació ex post. Els òrgans de control intern haurien de vetllar perquè tota actuació pública compleixi amb la normativa i també es faci de la forma més eficaç i eficient. Els òrgans de control extern, que actuen per compte dels Parlaments, tenen la missió de controlar l’acció dels governs en termes de compliment de legalitat i de regularitat financera i també de que les intervencions públiques assoleixen els seus objectius i que s’obté el que els anglosaxons anomenen “Value for Money” (valor del diner en termes d’increment del benestar social). Finalment, els Parlaments, fan un control polític de l’acció de govern.
És rellevant que tots aquests nivells de control funcionin i que cadascú exerceixi el seu paper. Per això, el disseny institucional d’un país hauria de dotar-se de normes, estructures orgàniques, personal capacitat i xarxes i aliances per poder dur a terme aquests papers de forma adequada.
La Sindicatura de Comptes de Catalunya està en una posició rellevant per les seves característiques d'entitat de fiscalització externa, amb un gran coneixement del sector públic i sotmesa als principis d'independència , objectivitat, rigor, professionalitat i transparència. Aquesta singularitat com a òrgan de control extern diferencia el seu paper d’altres agents de control i avaluació que conviuen en aquest ecosistema i el centra particularment en la garantia del bon ús dels recursos públics. Per poder exercir millor aquesta missió l’estratègia de la Sindicatura de Comptes per als propers anys està centrada en anar més enllà del control financer i de legalitat i impulsar les auditories operatives i utilitzar els mètodes de l’avaluació de polítiques públiques per vetllar per l’ús eficaç i eficient dels recursos públics
