Contracte de cercetare

CONTRIBUTII LA PROIECTAREA NANO/MICRO MECANISMELOR FLEXIBILE DE ACTIONARE SI DETECTIE

CNCSIS, Proiect A, 2005-2007

Director contract: Nicolae Lobontiu

Rezumat

Proiectul adreseaza modelarea, proiectarea, fabricarea si caracterizarea nano/microsistemelor mecanice flexibile cu aplicatii in microscopia atomica

si detectarea de substante periculoase prin utilizarea unor metode relativ simple cum ar fi nano/microgrinzile (microcantilevers) si prin monitorizarea

raspunsului static si rezonant (dinamic). Proiectul studiaza noi forme geometrice care sa permita selectarea rapida a configuratiei de nano/microgrinda

in raport cu criterii de optimizare statice si dinamice.

Doua metode originale, una analitica si alta cu elemente finite, sunt dezvoltate pentru proiectarea acestor microdispozitive pe baza proprietatilor de

rigiditate, inertie si viscozitate. Modelele sunt folosite la proiectarea si microfabricarea unui set de prototipuri care sunt testate atat experimental cat

si numeric. O metoda de optimizare este propusa, de cuplare a formei si dimensiunilor microstructurilor cu criterii de performanta dorite in regim static

sau dinamic.

Abstract

The project addresses the modeling, design, fabrication and testing of compliant nano/micro systems with applications in atomic force microscopy

and hazardous substance detection. Simple structures can be used for these applications, such as nano/micro cantilevers whose static and resonant

responses are monitored. The project studies new geometries which enable quick selection of the adequate configuration based on static/dynamic

optimization criteria. Two original methods are proposed, one is analytic and the other is finite element based, to design these microstructures

based on stiffness, inertia and damping properties. These methods are used to design and fabricate several prototypes, which are going to be

tested both experimentally and numerically. An optimization method is also developed allowing for coupling between structural geometry and system

performance in the static and dynamic domains.

Participanti: UTCN, Institutul de Microtehnologie, Bucuresti

CERCETARI PRIVIND COMPORTAREA LA IMPACT A PROFILELOR CU PERETI SUBTIRI CU APLICATII IN SECURITATEA AUTOVEHICULELOR RUTIERE DE FABRICATIE ROMANEASCA

CNCSIS, Proiect Td, 2004-2006

Director contract: Vlad Muntean

Proiectul propus este important si are o complexitate deosebita. Realizarea acestuia presupune utilizarea modelelor analitice de calcul a deformatiilor si energiilor de impact, destul de restrictive si cu o aproximatie buna doar pe modele simplificate si in speta liniare (material cu comportament liniar, geometrii simple, conditii pe frontiera liniare), cu metode experimentale si cu cele numerice (metoda element finit MEF).

Tema proiectului este de o mare actualitate deoarece este strans legata de securitatea circulatiei rutiere cu aplicatie directa in securitatea pasiva a autovehicolului - structura caroseriei, bare de protectie, elemente de rigiditate - in securitatea drumurilor (parapeti laterali de tabla, stalpii panourilor publicitare).

Se urmareste stabilirea formei optime a unui profil din tabla subtire laminata, avand capacitate de deformare si de captare a energiei marite precum si posibilitatile acestuia de a fi utilizat in structura de rezistenta a autovehiculului autohton (stalpi de rezistenta, bare de protectie, elemente de soc) in scopul maririi sigurantei pasive a autovehicolului in cauza.

- Stabilirea unei metodologii de calcul a deformatiilor si energiilor de deformare a barelor cu diferite profile la solicitarea de impact in domeniul de solicitare elastic si plastic;

- Experimentarea comportamentului acestor bare profilate la solicitarea de impact;

- Simularea numerica a modelelor puternic neliniare ce reprezinta impactul a doua corpuri.

Se urmareste realizarea unei metodologii de calcul a barelor folosite in componenta elementelor de securiate a autovehicolului sau a caii rutiere. Cercetarile teoretice se vor completa prin realizarea unor experimente in timp si la scara reala a modelelor analitice si numerice propuse, pentru a valida metodologia in lucru, urmand apoi realizarea unei metodologii de simulare numerica a impactului care sa fie utilizabila pentru modele mai complexe.

The project we proposed is important and has a high level of complexity. To accomplish the main tasks, is required the use of analytical methods to compute the displacements and the impact energies, quite restrictive and with a good approximation only on simplified models, linear models (linear materials, simple geometries, simple boundary conditions), combined with experimental methods and numerical methods. The project theme is very actual due the reliance with the vehicle passive safety - auto body structure, frame work, strengths elements - and the road safety - guardrails, different structures. We try to determinate the optimal shape of a beam section made of thin metal sheets, having a great capacity to take impact energies and impact deformations, and also its possibility to be used in the strengths structure of a romanian vehicle in order to increase its passive safety.

- to establish an analytical methodology to compute deformations and impact energies at beams with different shapes, in the elastic-plastic domain;

We intend to develop an analytic methodology to compute beam elements from the vehicle structure and road environment structure. The theoretical researches will be followed by experiments in real time and at real scale to validate the mathematical model. Another goal is to develop a methodology for numerical simulation capable to analyze large and complex models.

STUDIUL SOLICITARILOR TERMO-MECANICE IN MOTOARELE CU ARDERE INTERNA UTILIZAND METODE MODERNE DE CERCETARE

CNCSIS, Proiect Td, 2004-2006

Director contract: Adrian-Ioan Botean

Obiectivul principal al acestei lucrari este prezentarea unui demers in vederea stabilirii conditiilor de realizare a transferului termic si a solicitarilor termo-mecanice in motoarele cu ardere interna cu piston, in particular al pieselor mobile si al celor fixe care invecineaza camera de ardere. Prin aceasta lucrare se incearca sa se stabileasca regimul si solicitarile termice si mecanice, particularizate pentru motoarele cu aprindere prin comprimare (mac) si motoare cu aprindere prin scanteie (mas). Se definesc conceptele de baza utilizate in cadrul acestui demers iar apoi, se prezinta procesul elaborarii unui model de calcul, fiecare etapa a acestuia facand obiectul unui capitol distinct. Studiul face apel la cele mai moderne metode de analiza numerica si experimentala: metode optice (fotoelasticimetrie, interferometrie), metode electrice (tensiometrie), spectroscopie, metoda elementului finit.

The main goal of this work is to establish the achievement conditions of the heat transfer and thermo-mechanical loads in burning spark engine with piston, particular for the mobile and fixed pieces near to burning room. This paper try to establish the thermal working conditions and stresses, in particular for the burning compression engines (mac) and burning spark engine (mas). It is defined the general notions and then it present the elaboration process of a calculus mode, each step being the object of a separate chapter. The study uses the most recent numeric and experimental analysis methods: optical methods (photoelasticimetry, interferometry), electrical methods (tensometry), spectroscopy and finite element analysis method.

METODE MODERNE DE CALCUL NUMERIC SI EXPERIMENTAL A ELEMENTELOR ELASTICE DE TIP MEMBRANA

CNCSIS, Proiect At, 2004-2005

Director contract: Mircea Dudescu

Proiectul a realizat si implementat solutii experimenatle moderne de analiza non contact, pe intreg domeniul analizat (full-field) prin metoda franjelor Moire a elementelor elastice de tip membrana cu aplicatii in mecanica fina, micromecanica, biomecanica si actionari de precizie. Rezultatele si metodele dezvoltate au fost utilizate la descrierea completa a comportamentului membranelor elastice metalice si mai ales nemetalice cu larga aplicabilitate in tehnica. Metoda de investigare utilizata, a Moire-ului de umbre cu modificarea fazei este complet computerizata si se bazeaza pe un echipament performant de captura si prelucrare a imaginilor. In paralel a fost dezvoltata si o aplicatie aplicatie software utilizind limbajul MATLAB, aplicatie dedicata calculului si trasarii caracteristicii membranei pe baza deformatiilor obtinute in urma analizelor experimentale prin metode Moire-ului de umbre. Au fost dezvoltati algoritmi de calcul care sa permita selectarea si citirea rezultatelor experimentale, calculul deformatiilor maxime, trasarea caracteristicii membranei si interpretarea rezultatelor.

Implicatiile cercetarii au fost multidisciplinare si cuprind domeniul mecanicii experimentale prin realizarea unui stand de incercare si utilizarea echipamentului din dotare pe aplicatii practice, domeniul analizei numerice prin aplicarea metodei elementului finit la studiul membranelor in domeniul deplasarilor mari si respectiv domeniul programarii calculatoarelor. Rezultatele proiectului au si un pronuntat caracter didactic prin popularizarea metodelor optice de analiza a deformatiilor in rindul tinerilor doctoranzi si al absolventilor.

Proposal has implemented a modern full-field and non-contact analysis method based on phase shifting shadow Moiré technique for thin membranes characterization. Thin membranes have many applications in fine mechanics, micromechanics, actuators and biomechanics. The research results and developed methods has been used to fully describe the membranes behaviour, both metallically and non-metallically. Analysis method – shadow Moiré with phase shifting- is fully automatic and uses new equipment for image acquisition and analysis. In the same time a MATLAB software module has been developed to process experimental data in order to present full-field membranes displacement and to draw the membranes characteristic. Were defined algorithms to import data, to compute maximum displacement and membrane characteristic and to analyse the results.

The research had a multidisciplinary character and included mechanics of materials, optical methods for displacements analysis and computer programming. Investigation method was disseminated in the academia and the obtained results has been communicated at national and international conferences.