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| Comment on classical theory of stability analysis for truss structures |
| Revised:September 19, 2003 |
| View Full Text View/Add Comment Download reader |
| DOI：10.7511/jslx20053063 |
| KeyWord:truss,stability,critical load,buckling theory |
| SUN Huan-chun~* WANG Yue-fang |
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| Abstract: |
| The classical theory of stability analysis for truss structures is investigated in details. It points out that the critical load obtained from the classical theory is unreasonably too larger than the one from the local buckling theory. It showed that the problem is due to the basic assumptions of the classical theory: (1)the axial compressive internal force is considered uniquely proportional to the external loading till a buckling happens, (2)the members remain in straight lines before the buckling, (3) the buckling is developed by a large deformation, causing the structure to lose its load-carrying capacity, and (4) the critical load is unrelated to the cross-sectional moment as well as the absolute length of the members. The authors point out that the above mentioned assumptions should be modified. Based on the local buckling theory a new approach is developed for computation on the critical loads of the structures. In this approach, the load of an initially small value is increased to a certain amount that makes a set of members locally buckle. The internal forces of the buckled members are kept fixed in following load increment procedures. The load is added further till the whole structure becomes a mechanism or totally loses its load-bearing capacity. The final load will be the critical load of the global stability problem. |
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