scholarly journals A Genetic Algorithm Based Form-finding of Tensegrity Structures with Multiple Self-stress States

2017 ◽  
Vol 16 (1) ◽  
pp. 155-162 ◽  
Author(s):  
Seunghye Lee ◽  
Jaehong Lee ◽  
Joowon Kang
Keyword(s):  
Genetic Algorithm ◽  
Form Finding ◽  
Tensegrity Structures ◽  
Stress States

A Genetic Algorithm Approach for 2-D Tensegrity Form Finding

2014 ◽  
Vol 17 (11) ◽  
pp. 1669-1679 ◽  
Author(s):  
Shirko Faroughi ◽  
Mehdi Abdollahi Kamran ◽  
Jaehong Lee
Keyword(s):  
Genetic Algorithm ◽  
Objective Function ◽  
Stiffness Matrix ◽  
Equilibrium Configuration ◽  
Positive Definite ◽  
Connectivity Matrix ◽  
Form Finding ◽  
Numerical Examples ◽  
Tensegrity Structures ◽  
Genetic Algorithm Approach

This paper presents a novel and versatile method for finding 2-D tensegrity structures form finding. Using this method, different possibilities for the geometry of 2-D tensegrity structures can be found with little information about the structure. As opposed to most existing procedures this method only needs the number of each member prototype, the number of tensegrity nodes and connectivity at each node to be known. The form finding is done by minimizing objective function, which considers the rank deficiencies of the geometry, the prestress coefficients and the semi-positive definite condition of the stiffness matrix. Genetic algorithm as the global search is taken into account first for generating the connectivity matrix, initial prestress coefficients and also minimizing the objective function. Several numerical examples are given to demonstrate the competence and robustness of the current study in searching new different possibility self-equilibrium configuration of tensegrity structures.

Form-finding of free-form tensegrity structures by genetic algorithm–based total potential energy minimization

2016 ◽  
Vol 20 (5) ◽  
pp. 784-796 ◽  
Author(s):  
Fatih Uzun
Keyword(s):  
Genetic Algorithm ◽  
Potential Energy ◽  
Free Form ◽  
Stable Form ◽  
Equilibrium Form ◽  
Form Finding ◽  
Tensegrity Structures ◽  
Computational Performance ◽  
Stability Of Structures

Free-form tensegrities are composed of randomly connected cable and strut elements. The complexity of these structures causes determination of their self-equilibrium form to be a formidable task. There can be an infinite number of solutions with different forms, but it is difficult to identify the best form in terms of stability. Based on the fact that stability of structures is inversely proportional to potential energy, a genetic algorithm minimization process is developed to determine the self-equilibrium form of free-form regular tensegrity structures. The capability of the form-finding process on determination of the most stable form with minimum potential energy is investigated using two main parameters of free-form regular tensegrities which are cable–strut length ratio at rest and number of strut elements. The computational performance of the proposed method is also tested using free-form tensegrities with different number of structural elements.

scholarly journals A novel method for determining the feasible integral self-stress states for tensegrity structures

2021 ◽  
Vol 8 (1) ◽  
pp. 70-88
Author(s):  
Aguinaldo Fraddosio ◽  
Gaetano Pavone ◽  
Mario Daniele Piccioni
Keyword(s):  
Form Finding ◽  
Tensegrity Structures ◽  
Innovative Method ◽  
Symmetry Properties ◽  
Nodal Coordinates ◽  
Novel Method ◽  
Equilibrium Matrix ◽  
Stress States ◽  
Value Decomposition ◽  
External Loads

Abstract The form-finding analysis is a crucial step for determining the stable self-equilibrated states for tensegrity structures, in the absence of external loads. This form-finding problem leads to the evaluation of both the self-stress in the elements and the shape of the tensegrity structure. This paper presents a novel method for determining feasible integral self-stress states for tensegrity structures, that is self-equilibrated states consistent with the unilateral behaviour of the elements, struts in compression and cables in tension, and with the symmetry properties of the structure. In particular, once defined the connectivity between the elements and the nodal coordinates, the feasible self-stress states are determined by suitably investigating the Distributed Static Indeterminacy (DSI). The proposed method allows for obtaining feasible integral self-stress solutions by a unique Singular Value Decomposition (SVD) of the equilibrium matrix, whereas other approaches in the literature require two SVD. Moreover, the proposed approach allows for effectively determining the Force Denstiy matrix, whose properties are strictly related to the super-stability of the tensegrity structures. Three tensegrity structures were studied in order to assess and discuss the efficiency and accuracy of the proposed innovative method.

Novel Form-Finding of Tensegrity Structures Using Ant Colony Systems

2012 ◽  
Vol 4 (3) ◽  
Author(s):  
Yao Chen ◽  
Jian Feng ◽  
Yongfen Wu
Keyword(s):  
Ant Colony ◽  
Physical Models ◽  
Ant Colony System ◽  
Form Finding ◽  
Tensegrity Structures ◽  
Stress States ◽  
Feasible Solutions ◽  
The Stability ◽  
Ant Colony Systems ◽  
External Loads

Tensegrity structures have remarkable configurations and are drawing the attention of architects and engineers. They possess inextensional mechanisms and self-stress states at a static equilibrium configuration under no external loads. For geometry with its nodes fixed, different connectivity patterns of the compression bars and tension cables might bring some novel tensegrity structures. Thus, form-finding is the key to designing novel tensegrity structures. Here, we develop a discrete optimization model for the form-finding and convert it into a modified traveling salesman problem (TSP). The ant colony system (ACS) is used to search for feasible solutions, where all the predetermined nodes are taken as different cities in the network. An objective function that considers the stability and the relative stiffness is developed to obtain the optimized configurations of tensegrity structures. Examples based on some regular geometries (including a hexagon and two polyhedra) and two nonregular geometries are carried out using the proposed technique. Many different configurations of the pin-jointed assemblies are transformed into interesting tensegrity structures. To verify the proposed method, some physical models are constructed and compared to the tensegrity structures obtained from the form-finding process. We conclude that this novel algorithm can be applicable to the form-finding of both regular and nonregular tensegrity structures.

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