Publication detail

Research of Effects of Defects on Stability Failures of Semi-monocoque Stiffeners

KATRŇÁK, T. JURAČKA, J. JEBÁČEK, I.

Czech title

Výzkum vlivu vad na ztráty stability výztuh poloskořepinových konstrukcí

English title

Research of Effects of Defects on Stability Failures of Semi-monocoque Stiffeners

Type

journal article in Scopus

Language

en

Original abstract

This article presents further results of the research of effects of model defects on the local buckling of compressed stiffeners in nonlinear finite element (FE) analyses. The main outcomes are confirmation of trends for 10 sets of profile dimensions, final validations of various sets of FE simulations, and designs of practical types of defects with appropriate ratio values. A single node defect and then complex types of defects with alternating distributions of node shifts along one edge, two free flange edges, one flange surface and both flange surfaces are analyzed in this research project. First parts of this paper describe designed FE models with defects, their effects on simulation results, colored graphic visualizations with stress scales and determinations of the sudden failure of stability in the local mode. Then, particular results of FE analyses are validated by a comparison with the results of analytical methods of stability failure. Final detail comparisons of analytical and FE simulation results with data of experimental tests confirm predicted critical buckling forces. The validation of results and design parameters together with the knowledge of effects of model defects on buckling behaviors allows more accurate simulations of internal stiffeners of thin-walled semi-monocoque structures.

Czech abstract

Tento článek prezentuje topometrickou optimalizaci kritické poloskořepinové konstrukce křídla dopravního letounu v kategorii pro sběrnou dopravu podle leteckého předpisu CS-23 (EASA 2012). Při výpočtech jsou použity moderní optimalizační metody konečných prvků. Hlavním výsledkem je významná úspora hmotnosti frézovaného integrálního spodního panelu křídla pomocí optimalizace tloušťky každého segmentu potahu. V tomto článku je popsána validace MKP modelu pomocí analytického softwaru a výběr konstrukčních omezení a požadavků na optimalizaci. Také závěrečná pevnostní kontrola a komplexní kontrola únosnosti konstrukce potvrdily požadované vlastnosti navržených konstrukčních modifikací s optimálním rozložením napětí. Následně byla provedena vyhodnocení hmotnostních úspor a prodloužení únavové životnosti podle metodologie s přípustným poškozením (Damage tolerance).

English abstract

This article presents further results of the research of effects of model defects on the local buckling of compressed stiffeners in nonlinear finite element (FE) analyses. The main outcomes are confirmation of trends for 10 sets of profile dimensions, final validations of various sets of FE simulations, and designs of practical types of defects with appropriate ratio values. A single node defect and then complex types of defects with alternating distributions of node shifts along one edge, two free flange edges, one flange surface and both flange surfaces are analyzed in this research project. First parts of this paper describe designed FE models with defects, their effects on simulation results, colored graphic visualizations with stress scales and determinations of the sudden failure of stability in the local mode. Then, particular results of FE analyses are validated by a comparison with the results of analytical methods of stability failure. Final detail comparisons of analytical and FE simulation results with data of experimental tests confirm predicted critical buckling forces. The validation of results and design parameters together with the knowledge of effects of model defects on buckling behaviors allows more accurate simulations of internal stiffeners of thin-walled semi-monocoque structures.

Keywords in Czech

ztráta stability; stabilita; porucha; pevnostní kontrola; metoda konečných prvků; výztuha; imperfekce

Keywords in English

buckling; stability; failure; stress analysis; finite element methods; stiffener; imperfection

Released

22.01.2020

Publisher

Vilnius Gediminas Technical University (VGTU) Press

Location

Vilnius, Litevská republika

ISSN

1648-7788

Volume

23

Number

3

Pages from–to

83–90

Pages count

8

BIBTEX


@article{BUT163580,
  author="Tomáš {Katrňák} and Jaroslav {Juračka} and Ivo {Jebáček},
  title="Research of Effects of Defects on Stability Failures of Semi-monocoque Stiffeners",
  year="2020",
  volume="23",
  number="3",
  month="January",
  pages="83--90",
  publisher="Vilnius Gediminas Technical University (VGTU) Press",
  address="Vilnius, Litevská republika",
  issn="1648-7788"
}