Vol.3, No 13, 2003 pp. 729-738
UDC 629.73  624.042.1
COMPUTER SOFTWARE FOR THE STRESS ANALYSIS
OF REPAIRED AIRCRAFT STRUCTURES
WITH THE METHOD OF COMPOSITE PATCH REPAIR
George Tsamasphyros, Zaira Marioli-Riga, Chris Vrettos
Department of Mechanics, General Section, National Technical University of Athens
A computer program for the solution of fracture mechanics problems is presented. The software includes a mesh generator routine for the creation of the geometry and a finite element routine for the calculation of values under interest such as Stress Intensity Factors, Stresses etc. The program is capable of dealing with the stress analysis of cracked or corroded metallic aircraft structures. One of the most modern methods of repairing such types of damage is the composite patch repair method. The principal of the method is the application of a patch made of composite material (e.x. carbon, boron) over the damaged area. If the damage type is a crack the scope of the repair is the reduction of the Stress Intensity Factor in the metallic structure. In the case of a corrosion, the scope of the repair is the reduction of the Maximum Von Mises Stress in the metallic structure. The program described herein – assisted by its user friendly interface- is a tool for the quick analysis of the cases described above.
KOMPJUTERSKI SOFTVER ZA ANALIZU NAPONA POPRAVLJANIH VAZDUHOPLOVNIH STRUKTURA METODOM POPRAVKE MEŠOVITIM KRPLJENJEM
Prikazan je kompjuterski program za rešavanje problema mehanike loma. Softver uključuje rutinu okastog generatora za stvaranje geometrije, i rutinu konačnog elementa za izračunavanje vrednosti koje su ispod interesa, kao što su faktori intenziteta napona, naponi itd. Program je u stanju da se bavi analizom napona naprslih ili korodiranih metalnih vazduhoplovnih struktura. Jedna od najmodernijih metoda popravke takvih vrsta oštećenja je metoda mešovite popravke krpljenjem. Osnova metode je postavljanje zakrpe načinjene od mešovitog materijala (npr. ugljenik, bor) preko oštećene oblasti. Ako je vrsta oštećenja prslina, popravka se sastoji u smanjenju faktora intenziteta napona u metalnoj strukturi. U slučaju korozije, popravka se sastoji u smanjenju maksimalnog Von Mizes napona u metalnoj strukturi. Ovde opisani program – uz pomoć njegovog user friendly okruženja- orudje je za brzu analizu gore opisanih slučajeva.