Title page for ETD etd-01132005-132131


Document Type Master's Dissertation
Author Viljoen, Awie
URN etd-01132005-132131
Document Title Analysis and Optimum Design of stiffened shear webs in airframes
Degree MEng (Mechanical and Aeronautical Engineering)
Department Mechanical and Aeronautical Engineering
Supervisor
Advisor Name Title
Mr A G Visser Co-Supervisor
Prof A A Groenwold Supervisor
Keywords
  • genetic algorithm
  • structural optimization
  • FORTRAN program
  • shear web
  • aircraft structures
  • non-linear finite element analysis
  • NACA
  • diagonal tension
  • Grisham algorithm
  • post-buckling analysis
Date 2004-03-03
Availability unrestricted
Abstract
The analysis and optimum design of stiffened, shear webs in aircraft structures is addressed. The post-buckling behaviour of the webs is assessed using the interactive algorithm developed by Grisham. This method requires only linear finite element analyses, while convergence is typically achieved in as few as five iterations. The Grisham algorithm is extensively compared with empirical analysis methods previously used for aircraft structures and also with a refined, non-linear quasi-static finite element analysis.

The Grisham algorithm provides for both compressive buckling in two directions as well as shear buckling, and overcomes some of the conservatism inherent in conventional methods of analysis. In addition, the method is notably less expensive than a complete non-linear finite element analysis, even though global collapse cannot be predicted. While verification of the analysis methodology is the main focus of the stud, an initial investigation into optimization is also made. In optimizing stiffened thin walled structures, the Grisham algorithm is combined with a genetic algorithm. Allowable stress constraints are accommodated using a simple penalty formulation.

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  00front.pdf 2.84 Mb 00:13:08 00:06:45 00:05:54 00:02:57 00:00:15
  01chapter1.pdf 13.77 Mb 01:03:45 00:32:47 00:28:41 00:14:20 00:01:13
  02chapter2.pdf 7.96 Mb 00:36:50 00:18:56 00:16:34 00:08:17 00:00:42
  03chapter3.pdf 37.56 Mb 02:53:53 01:29:25 01:18:15 00:39:07 00:03:20
  04chapter4.pdf 785.96 Kb 00:03:38 00:01:52 00:01:38 00:00:49 00:00:04
  05chapter5.pdf 19.12 Mb 01:28:30 00:45:31 00:39:49 00:19:54 00:01:41
  06chapter6.pdf 3.61 Mb 00:16:43 00:08:36 00:07:31 00:03:45 00:00:19
  07chapter7.pdf 415.70 Kb 00:01:55 00:00:59 00:00:51 00:00:25 00:00:02
  08bibliography.pdf 205.64 Kb 00:00:57 00:00:29 00:00:25 00:00:12 00:00:01
  09appendices.pdf 3.08 Mb 00:14:14 00:07:19 00:06:24 00:03:12 00:00:16

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