Properties of Twofold Tape Loops: The Influence of the Subtended Angle

2019 ◽  
Vol 11 (2) ◽  
Author(s):  
Marinus G. de Jong ◽  
Werner W. P. J. van de Sande ◽  
Just L. Herder
Keyword(s):  
Energy Distribution ◽  
Cross Section ◽  
Energy State ◽  
Linear Guide ◽  
Curvature Analysis ◽  
Transverse Curvature ◽  
Thin Walled Structures ◽  
Constant Radius ◽  
Thin Walled ◽  
Key Aspects

Tape springs are thin-walled structures with zero longitudinal and constant transverse curvature. Folding them twice and connecting both ends creates a tape loop which acts as a linear guide. At this time, there is insufficient understanding of the influence of the tape spring's cross section on its behavior. This study investigates the influence of the subtended angle on the tape spring's behavior, especially the energy distribution and the fold radius. First, some key aspects in the design of a twofold tape loop are discussed. By performing a curvature analysis of this folded geometry, the different regions within a tape spring are identified. This information is used to identify the influence of the subtended angle on the geometry and energy state of the tape loop. The fold radius and fold angle are determined by analyzing the geometry of the fold region. The analysis showed that the energy within the transition regions cannot be neglected. The energy within these regions and the length of the transition regions both increase with the subtended angle. It is also shown that the fold radius is not constant when the subtended angle is small. The subtended angle should be above 100 deg to ensure a constant radius.

Influence of the Subtended Angle on the Behavior of Folded Tape Springs

2018 ◽  
Author(s):  
Marinus G. de Jong ◽  
Werner W. P. J. van de Sande ◽  
Just L. Herder
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Strain Energy ◽  
Element Model ◽  
Constant Cross Section ◽  
Curvature Analysis ◽  
Thin Walled Structures ◽  
Constant Radius ◽  
Thin Walled ◽  
Force Generator

Tape springs are thin-walled structures with zero longitudinal and constant transverse curvature. Folding them twice and connecting both ends creates a tape loop which acts as a linear guide. When using a tape spring with a non-constant cross-section, a force generator can be created. At this time there is insufficient understanding of the influence of the tape spring’s cross-section on its behavior. This study investigates the influence of the subtended angle on the tape spring’s behavior, especially the energy distribution and the fold radius. A tape spring is once folded in a finite element model. By performing a curvature analysis of this folded geometry, the different regions within a tape spring are identified. This information is used to identify the amount of strain energy of each region. Finally, the fold radius and fold angle are determined by analyzing the geometry of the bent region. The analysis showed that the energy within the transition regions cannot be neglected. The energy within these regions as ratio of the total energy and the length of the transition regions both increase with the subtended angle. It is also shown that the fold radius is not constant when the subtended angle is small. Therefore, when designing a force generator using tape loops, the energy within the transition regions should be taken into account. The subtended angle should not be small to ensure a constant radius.

Numerical Investigation of Cross-Section on Aluminum A6063 Thin-Walled Structures under Low-Velocity Impact Loading

2014 ◽  
Vol 1019 ◽  
pp. 96-102
Author(s):  
Ali Taherkhani ◽  
Ali Alavi Nia
Keyword(s):  
Energy Absorption ◽  
Cross Section ◽  
Cross Sections ◽  
Peak Load ◽  
Circular Cross Section ◽  
Absorption Capacity ◽  
Energy Absorption Capacity ◽  
Thin Walled Structures ◽  
Thin Walled ◽  
Crush Strength

In this study, the energy absorption capacity and crush strength of cylindrical thin-walled structures is investigated using nonlinear Finite Elements code LS-DYNA. For the thin-walled structure, Aluminum A6063 is used and its behaviour is modeled using power-law equation. In order to better investigate the performance of tubes, the simulation was also carried out on structures with other types of cross-sections such as triangle, square, rectangle, and hexagonal, and their results, namely, energy absorption, crush strength, peak load, and the displacement at the end of tubes was compared to each other. It was seen that the circular cross-section has the highest energy absorption capacity and crush strength, while they are the lowest for the triangular cross-section. It was concluded that increasing the number of sides increases the energy absorption capacity and the crush strength. On the other hand, by comparing the results between the square and rectangular cross-sections, it can be found out that eliminating the symmetry of the cross-section decreases the energy absorption capacity and the crush strength. The crush behaviour of the structure was also studied by changing the mass and the velocity of the striker, simultaneously while its total kinetic energy is kept constant. It was seen that the energy absorption of the structure is more sensitive to the striker velocity than its mass.

scholarly journals Primary Response Assessment Method for Concept Design of Monotonous Thin-Walled Structures

10.14311/750 ◽  
2005 ◽  
Vol 45 (4) ◽  
Author(s):  
V. Zanic ◽  
P. Prebeg
Keyword(s):  
Cross Section ◽  
Response Assessment ◽  
Assessment Method ◽  
Primary Response ◽  
Concept Design ◽  
Fem Model ◽  
Feasibility Assessment ◽  
Thin Walled Structures ◽  
Thin Walled ◽  
The Cross

A concept design methodology for monotonous, tapered thin-walled structures (wing/fuselage/ship/bridge) is presented including modules for: model generation; loads; primary (longitudinal) and secondary (transverse) strength calculations; structural feasibility (buckling/fatigue/ultimate strength criteria); design optimization modules based on ES/GA/FFE; graphics. A method for primary strength calculation is presented in detail. It provides the dominant response field for design feasibility assessment. Bending and torsion of the structure are modelled with the accuracy required for concept design. A ‘2.5D-FEM’ model is developed by coupling a 1D-FEM model along the ‘monotonity’ axis and a 2D-FEM model(s) transverse to it. The shear flow and stiffness characteristics of the cross-section for bending and pure/restrained torsion are given, based upon the warping field of the cross-section. Examples: aircraft wing and ship hull. 

scholarly journals Fem and Experimental Analysis of Thin-Walled Composite Elements Under Compression

2017 ◽  
Vol 22 (2) ◽  
pp. 393-402 ◽  
Author(s):  
P. Różyło ◽  
P. Wysmulski ◽  
K. Falkowicz
Keyword(s):  
Numerical Analysis ◽  
Cross Section ◽  
Numerical Models ◽  
Fem Analysis ◽  
Geometrical Parameters ◽  
Loss Of Stability ◽  
Composite Columns ◽  
Thin Walled Structures ◽  
Operating Stability ◽  
Thin Walled

Abstract Thin-walled steel elements in the form of openwork columns with variable geometrical parameters of holes were studied. The samples of thin-walled composite columns were modelled numerically. They were subjected to axial compression to examine their behavior in the critical and post-critical state. The numerical models were articulately supported on the upper and lower edges of the cross-section of the profiles. The numerical analysis was conducted only with respect to the non-linear stability of the structure. The FEM analysis was performed until the material achieved its yield stress. This was done to force the loss of stability by the structures. The numerical analysis was performed using the ABAQUS® software. The numerical analysis was performed only for the elastic range to ensure the operating stability of the tested thin-walled structures.

scholarly journals Numerical Models of the Connection of Thin-Walled Z-Profile Roof Purlins

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6573
Author(s):  
Přemysl Pařenica ◽  
Petr Lehner ◽  
Jiří Brožovský ◽  
Martin Krejsa
Keyword(s):  
Cross Section ◽  
Numerical Models ◽  
Element Model ◽  
Cross Sectional ◽  
Physical Test ◽  
Thin Walled Structures ◽  
Practical Design ◽  
Thin Walled ◽  
Bolt Connection ◽  
Experimental Preparation

High thin-walled purlins of Z cross-section are important elements in steel wide-span structures. Their behaviour is influenced by many variables that need to be examined for every specific case. Their practical design thus requires extended knowledge of their behaviour for the possible configurations and dimensions. Numerical analysis verified by experimental investigation can thus enrich such knowledge. Numerical models have the advantage of repeatability and the ability to offer parametric changes. The parametric study presented shows a detailed description of a finite element model of thin-walled cross-sectional roof purlins connected to other roof elements. Models include various approaches to modelling bolt connection. Two schemes of purlins, with and without cleats, are presented. The results of different approaches in numerical modelling are compared with the results of a physical test on a real structure. The article shows a significant agreement in the case of specific approaches and points out the differences with others. The results can be helpful in terms of how to approach the modelling of thin-walled structures and the effective approach to experimental preparation.

scholarly journals Applicability of thin-walled structures for energy-savings in steel construction

2019 ◽  
Vol 91 ◽  
pp. 02042
Author(s):  
Natalia D. Korsun ◽  
Daria A. Prostakishina
Keyword(s):  
Cross Section ◽  
Energy Savings ◽  
Effective Characteristics ◽  
Geometric Imperfections ◽  
Thin Walled Structures ◽  
Steel Construction ◽  
Full Cross Section ◽  
Initial Geometric Imperfections ◽  
Thin Walled ◽  
The Cross

The paper discusses the use of lightweight thin-walled structures which make it possible to save resources in steel construction. The highlighted challenges that this industry face in the Russian Federation involve insufficient development of the domestic standards. A thin-walled sigma-profile element with 300 mm in a section height has been studied. The element, its design diagram and loading have been chosen taking into account the structural performance of the columns and girders involved in CFS frameworks. The paper presents analysis technique for a thin-walled profile which performs under axial compression and axial bending compression. The structures have been calculated taking into account their main feature - the initial geometric imperfections. The analysis of the changed effective characteristics and stresses in the cross-section has revealed the significant influence of the initial geometric imperfections of the profiles and location of the extra eccentricity against the element’s initial curvatures. The elastic-plastic behaviour of material occurs when the stresses in the full cross-section achieve 0.71 Ryignoring the initial geometric imperfections, and 0.58 Ry– with regard to them. The paper substantiates the need to consider unevenness of the mechanical properties of steel distributed over the cross-section of the profile. Based on the experimental data obtained, conclusions have been drawn on the necessary adaptation of the indirect method for evaluating the strength characteristics of thin-walled samples.

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