Form-finding bending-active structures with temporary ultra-elastic contraction elements

2014 ◽  
Author(s):  
J. Lienhard ◽  
R. La Magna ◽  
J. Knippers
Keyword(s):  
Form Finding ◽  
Active Structures

scholarly journals Mechanical models in computational form finding of bending-active structures

2018 ◽  
Vol 33 (2) ◽  
pp. 86-97 ◽  
Author(s):  
Carlos Lázaro ◽  
Juan Bessini ◽  
Salvador Monleón
Keyword(s):  
Three Dimensional ◽  
Beam Theory ◽  
Task Type ◽  
Degree Of Freedom ◽  
Complex Nature ◽  
Dynamic Relaxation ◽  
Form Finding ◽  
Beam Elements ◽  
Active Structures ◽  
Computational Form

This article reviews the different aspects involved in computational form finding of bending-active structures based on the dynamic relaxation technique. Dynamic relaxation has been applied to form-finding problems of bending-active structures in a number of references. Due to the complex nature of large spatial deformations of flexible beams, the implementation of suitable mechanical beam models in the dynamic relaxation algorithm is a non-trivial task. Type of discretization and underlying beam theory have been identified as key aspects for numerical implementations. References can be classified into two groups depending on the selected discretization: finite-difference-like and finite-element-like. The first group includes 3- and 4-degree-of-freedom implementations based on increasingly complex beam models. The second gathers 6-degree-of-freedom discretizations based on co-rotational three-dimensional Kirchhoff–Love beam elements and geometrically exact Reissner–Simo beam elements. After reviewing and comparing implementation details, the advantages and drawbacks of each group have been discussed, and open aspects for future work have been pointed out.

Teaching Tension Structures

2002 ◽  
Vol 17 (2-3) ◽  
pp. 171-181
Author(s):  
Marijke Mollaert
Keyword(s):  
Physical Models ◽  
Real Case ◽  
Structural Systems ◽  
Form Finding ◽  
Active Structures ◽  
Tension Structures

The main purpose of the course “Form Active Structures” [6] is to waken the students' interest in the design of space and structural systems and to clarify the principles to obtain lightweight constructions. Concepts, calculation techniques, detailing and erection are first illustrated. The practical part linked to this course consists of four topics: building physical models, numerical form-finding and analysis, a study trip and the design for a real case. Especially in this last part the need to design both geometry and pretension together, and the consequences if this is not properly done, comes to the students' consciousness.

scholarly journals A fast and accurate dynamic relaxation approach for form-finding and analysis of bending-active structures

2019 ◽  
Vol 34 (1-2) ◽  
pp. 40-53
Author(s):  
Jef Rombouts ◽  
Geert Lombaert ◽  
Lars De Laet ◽  
Mattias Schevenels
Keyword(s):  
Computation Time ◽  
High Accuracy ◽  
Dynamic Relaxation ◽  
Time Step ◽  
Form Finding ◽  
Form Complex ◽  
Beam Elements ◽  
Active Structures ◽  
Newton Raphson ◽  
Raphson Method

Active bending is an increasingly popular construction technique that uses elastically bent structural members to form complex curved shapes. The design and analysis of bending-active structures requires an accurate simulation of the bending process, which is often complicated by the occurrence of large displacements. In this article, we propose to combine a previously developed implicit dynamic relaxation method with co-rotational beam elements to obtain a fast and accurate method for form-finding and analysis of bending-active structures. This approach is applied to four test cases. Implicit dynamic relaxation is compared to the classic Newton–Raphson method and conventional dynamic relaxation. The results show that the proposed implicit dynamic relaxation approach can be stabilized intuitively by changing the time step and damping ratio, making it more stable than the classic Newton–Raphson method. Moreover, the proposed approach converges fast compared to the conventional dynamic relaxation: the total computation time is considerably lower, even though the computation time per iteration is higher. Finally, a high accuracy is achieved due to the use of co-rotational beam elements. The combination of high accuracy and low computation time makes this approach well-suited for both form-finding and analysis of bending-active structures.

scholarly journals Floating-bending tensile-integrity structures

2021 ◽  
Vol 8 (1) ◽  
pp. 89-95
Author(s):  
Micol Palmieri ◽  
Ilaria Giannetti ◽  
Andrea Micheletti
Keyword(s):  
Structural Design ◽  
Membrane Systems ◽  
Limit States ◽  
Form Finding ◽  
Supported Membrane ◽  
Tensegrity Systems ◽  
Matlab Implementation ◽  
Diamond Type ◽  
Conceptual Work

Abstract This is a conceptual work about the form-finding of a hybrid tensegrity structure. The structure was obtained from the combination of arch-supported membrane systems and diamond-type tensegrity systems. By combining these two types of structures, the resulting system features the “tensile-integrity” property of cables and membrane together with what we call “floating-bending” of the arches, a term which is intended to recall the words “floating-compression” introduced by Kenneth Snelson, the father of tensegrities. Two approaches in the form-finding calculations were followed, the Matlab implementation of a simple model comprising standard constant-stress membrane/cable elements together with the so-called stick-and-spring elements for the arches, and the analysis with the commercial software WinTess, used in conjunction with Rhino and Grasshopper. The case study of a T3 floating-bending tensile-integrity structure was explored, a structure that features a much larger enclosed volume in comparison to conventional tensegrity prisms. The structural design of an outdoor pavilion of 6 m in height was carried out considering ultimate and service limit states. This study shows that floating-bending structures are feasible, opening the way to the introduction of suitable analysis and optimization procedures for this type of structures.

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