Contribuii privind proiectarea structurilor sudate de mas minim prezente pe aeronave

Contribuii privind proiectarea strucurilor sudate de mas minim prezente pe aeronave

Contribuii privind proiectarea structurilor sudate de mas minim prezente pe aeronave

Contribuii privind proiectarea structurilor sudate de mas minim prezente pe aeronave

Contributions regarding the design of the aircraft lightweight welded structures

Cond. t,

Doctorand,

Prof. Univ. Dr. Ing. BALCU Ion

Ing. DIMA Dumitru - Gabriel

Rezumatul tezei (lb. Rom + lb. Englez)

Cele mai ntlnite structuri sudate din componena aeronavelor sunt structuri de tip grind sau cu geometrii complexe, care trebuie s reziste sarcinilor impuse de regulamentele de certificare, n condiiile unei mase minime. n urma studiului literaturii de specialitate, a mai multor aeronave, dar i ca rezultat al unei activiti de proiectare i calcul n domeniul aeronautic, s-a constatat doar disponibilitatea unor cunotine calitative despre proiectarea de detaliu a acestor structuri. Plecnd de la acest considerent, s-a dezvoltat i validat experimental o metod de calcul bazat pe analiza cu elemente finite care, mpreun cu metodologiile de calcul ale structurilor tubulare din ingineria civil, s-au constituit ntr-un instrument pentru studiul structurilor sudate uoare.

n acest mod, s-a studiat influena pe care o au guseele asupra factorului concentratorilor de tensiune din jonciunile tubulare, ncepnd de la forma i amplasamentul acestora, pn la variaia parametrilor geometrici. Cercetrile au continuat cu determinarea forei capabile a jonciunilor sub solicitri compuse, respectiv modaliti de reducere a factorului concentratorilor de tensiune n jonciunile cu i fr guseu.

Ca parte integrant a acestui cercetri s-au realizat mai multe studii de caz, pentru diferite structuri puternic solicitate (fuselaj, suport motor, banchet pasageri sau suport armament acroat). n cadrul studiilor de caz s-au clarificat probleme precum: influena guseelor asupra comportamentului grinzilor plane i al unui schelet spaial, reproiectarea pentru mas minim, proiectarea bazat pe optimizarea topologic, respectiv o comparaie ntre concepte de proiect realizate prin diferite tehnologii de fabricaie.

Lucrarea de fa vine n ajutorul colectivelor de proiectani cu contribuii n domeniul proiectrii conceptuale, predimensionrii i calculului pentru mas structural minim i durabilitate maxim a structurilor sudate din domeniul aeronautic.***Most of the welded structures on aircrafts are latticed beams or complex shapes, having to withstand the certification loads for a minimum weight. After the documentation from dedicated literature, directly on aircrafts, and also by the activity of design and calculation of aircraft structures, it was found that only qualitative information about structural detail design are available. Starting from this point, a method based on the finite elements was developted and experimentaly validated. This, together with calculation methods of the tubular structures from civil industry, formed a tool for the lightweight welded structures.

Iut was studied the influence of the gussets over the stress concentration factor form tubular joints, taking into account shape, placement and all geoetrical parameters. The researches were continued with the capacity of mulltiloaded joints and methods to decrease the stress concentration factor of the joint with or without gusset.

As part of the research program, were few case studies for hevy loaded structures as a fuselage, an engine suport, a passenger seat or a weapon carrying system. There were clarified issues like the influence of the gussets over plane beams and spatial structures behavior, redesign of a structure for weight saving, design based on topology optimization and an assessment of some design concepts manufactured by different technologies.

The research program will asist engineering teams in conceptual design, dimensioning and calculation of the lightweight aircraft welded structures.

7873