On modeling and optimal design of beam - bridge structures

• Autorzy: Pedersen P. , Pedersen N. L.
• Języki publikacji: EN

Abstrakty

EN

To obtain black and white solutions (material or non-material) penalizations are applied, and due to problems of low density we can see a clear tendency toward solutions which more or less are truss or frame structures. Often, the accuracy of the finite element models for the continuum is then at its limits. For multiple load cases the formulation with a combination of individual load cases is in reality just as simple as for single load cases, but the design solution naturally depends on the selected combination factors, and we can illustrate this by a 3 D bridge example. It is still possible to obtain solutions by simple optimality criterion iterations which to a large extend, are used in this study. At first, the purpose of the presented paper is to make a comparison between optimal designs found by known methods for topology optimization of continuum structures and optimal designs of structures modeled as trusses. For a statically determined truss each bar can be designed independently and therefore must be fully stressed in an optimal design. We want to focus on the basic knowledge which gives an optimality criterion for single load eases with only a single constraint. Truss and continuum examples are analyzed, optimized, and evaluated to get further insight into the influence from the basic modeling, being truss or continuum. Stiffness as well as strength are important aspects of an optimal design.

Słowa kluczowe

EN

optimal design; truss; continuum; penalization; 3D bridge

PL

konstrukcja optymalna; kratownica; most

• Wydawca: Wydawnictwo Politechniki Poznańskiej
• Czasopismo: Foundations of Civil and Environmental Engineering
• Rocznik: 2006
• Tom: No. 7
• Strony: 273--291
• Opis fizyczny: Bibliogr. 10 poz.

Twórcy

autor

Pedersen P.

autor

Pedersen N. L.

• Department of Mechanical Engineering, Solid Mechanics Technical University of Denmark Nils Koppels Alle, Building 404, DK-2800 Kgs.Lyngby, Denmarka Tel.: [phone]; fax: [phone],

Bibliografia

• 1. Beckers, M. (1999). Topology optimization using a dual method with discrcte variables. Structural Optimization 17:14—24.
• 2. Diaz, A. R., and Bcndsee, M. P. (1992J. Shape optimization of structures for multiple loading conditions using a homogenization method. Stntctural Optimization 4:17-22.
• 3. Dorn, W. S., Gomory, R. E., and Grecnberg, H. J. (1964). Automatic design of optimal structures. J. de Mechaniąite 3:25-52.
• 4. Fleron, P. (1964). The minimum weight of trusses. Bygningsstatiske Medde!elser3>5:&\-96.
• 5. Gass, S. I. (1964). Linear Programmmg. Tokyo, Japan: McGraw-Hill, second edition. 280pages.
• 6. Hadley, G. (1964). Nonlinear and Dynamic Programmming. Addison-Wesley. 484 pages.
• 7. Pedersen, N. L., and Nielsen, A. K. (2003). Optimization of practical trusses with constraints on eigenfrequcncies, displacements, stresses and buckling. Struci. Multidisc. Optim. 25(5-6):436^45.
• 8. Pedersen, P. (1998). Some generał optimal design results using anisotropic power law non-linear elasticity. Structural Optimization 15:73-80.
• 9. Pedersen, P. (2003). Optimal Designs - Structures and Materials - Problems and Tools -. http://www.fam.web.mek.dtu.dk/pp.html. 314 pages.
• 10. Wasiutynski, Z. (1960). On the congruency of the forming according to thc minimum potential energy with that according to eąual strength. Buli. de 1'Academie Polonaise des Sciences, Serie des Sciences Techniąues 8(6):259-268.