Maio 2014 vol. 1 num. 1 - 10th World Congress on Computational Mechanics

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OPTIMUM PRE-STRESS DESIGN FOR FREQUENCY REQUIREMENT OF TENSEGRITY STRUCTURES

Safaei, Seif Dalil ; Eriksson, Anders ; Tibert, Gunnar ;

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Structures composed of tension and compression elements in equilibrium are de- noted tensegrity structures. Stability of tensegrity structures is achieved through introducing initial member forces (pre-stress). The pre-stress design can be seen consisting of three differ- ent stages: (i) finding the bases of possible pre-stress states, (ii) finding admissible distribu- tions considering unilateral properties of the elements and stability of the structure, (iii) find- ing the optimum pre-stress pattern for certain magnitude from compatible pre-stress states. So far, no research has been carried out to connect the three steps, i.e. finding a suitable pre- stress pattern which also considers mechanical properties of the highly pre-stressed structure e.g. its natural frequencies. This paper aims at finding an optimum pre-stress pattern and level of pre-stress for the maximum frequency. The pre-stress problem is on a linear static level where no slackening is allowed. An optimization is performed to find the optimum pre- stress pattern from the self-stress modes obtained by a singular value decomposition (SVD) of the equilibrium matrix. The objective function is the first natural frequency of the struc- ture. Finite element analysis is employed for the linear analysis of the structure and a genetic algorithm for optimization i.e., a non-gradient method. The example considered is a double layer tensegrity grid consisting of 29 independent self-stress states. The method is applicable to complex asymmetric three-dimensional structures. The new aspect of this work is a link between the SVD analysis, finite element analysis and genetic algorithm.

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Palavras-chave: Tensegrity structures, Pre-stress, Finite element analysis, Genetic algorithm.,

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DOI: 10.5151/meceng-wccm2012-18317

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Como citar:

Safaei, Seif Dalil; Eriksson, Anders; Tibert, Gunnar; "OPTIMUM PRE-STRESS DESIGN FOR FREQUENCY REQUIREMENT OF TENSEGRITY STRUCTURES", p. 1258-1270 . In: In Proceedings of the 10th World Congress on Computational Mechanics [= Blucher Mechanical Engineering Proceedings, v. 1, n. 1]. São Paulo: Blucher, 2014.
ISSN 2358-0828, DOI 10.5151/meceng-wccm2012-18317

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