Dynamic Testing of an Inflatable, Self-Supporting,  Unpressurized Thin-Film Torus

Haiping, Song; Smith, Suzanne; Main, John A.

doi:10.2514/1.16509

Cited by 16 publications

(5 citation statements)

References 6 publications

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“…Song et al [7] did the dynamic testing of a self-supporting inflatable torus. The excitation was provided by a loud speaker and the output was measured using a laser displacement vibrometer.…”

Section: Introductionmentioning

confidence: 99%

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Dynamic Testing of a Pre-stretched Flexible Tube for Identifying the Factors Affecting Modal Parameter Estimation

Unnikrishnan¹,

Rajan²,

Raghunathan³

et al. 2016

J. Inst. Eng. India Ser. C

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Experimental modal analysis is the primary tool for obtaining the fundamental dynamic characteristics like natural frequency, mode shape and modal damping ratio that determine the behaviour of any structure under dynamic loading conditions. This paper discusses about a carefully designed experimental method for calculating the dynamic characteristics of a pre-stretched horizontal flexible tube made of polyurethane material. The factors that affect the modal parameter estimation like the application time of shaker excitation, pause time between successive excitation cycles, averaging and windowing of measured signal, as well as the precautions to be taken during the experiment are explained in detail. The modal parameter estimation is done using MEscopeVESTM software. A finite element based pre-stressed modal analysis of the flexible tube is also done using ANSYS ver.14.0 software. The experimental and analytical results agreed well. The proposed experimental methodology may be extended for carrying out the modal analysis of many flexible structures like inflatables, tires and membranes.

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Section: Introductionmentioning

confidence: 99%

“…Though the references [6][7][8][9][10][11][12] describe the EMA of flexible structures, the case of a stretched horizontal flexible tube is not properly addressed in any of these papers. The present paper details the EMA of a polyurethane tube with 2 % pre-stretch.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Testing of a Pre-stretched Flexible Tube for Identifying the Factors Affecting Modal Parameter Estimation

Unnikrishnan¹,

Rajan²,

Raghunathan³

et al. 2016

J. Inst. Eng. India Ser. C

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“…Flint et al [7,8] examined doubly curved form-stiffened thin-film shells in which the membrane is manufactured such that, without adding mass, the final surface had permanent depth and curvature. Song et al [9] investigated a membrane torus with a 1.8 m ring diameter and a 0.2 m tube diameter. Unlike similar tori investigated by Griffith and Main [10] and Ruggiero et al [11], a regular pattern of convex hexagonal domes (8 mm side to side and 3.5 mm high) was formed into the polyimide film from which the torus was constructed.…”

Section: Introductionmentioning

confidence: 99%

Global Static Testing and Model Validation of Stiffened Thin-Film Polyimide Panels

Black

Leifer

Smith

2008

Journal of Spacecraft and Rockets

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Nomenclature E app = apparent modulus of a hollow beam E s = modulus of elasticity for the solid material E x = modulus of elasticity along the major axis E y = modulus of elasticity along the minor axis E 1 = modulus of elasticity along the 1 axis E 2 = modulus of elasticity along the 2 axis G 12 = shear modulus l = hexagon edge length t = hexagonal void spacing " i = strain along the i axis = internal angle of the hexagon ij = generic Poisson's ratio = volumetric density i = stress along the i axis

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“…This experiment motivated the researchers and industries for the development of lightweight inflatable structures for space applications. The ground-based experimental studies on torus structure were carried out by many researchers using different combination of actuators and sensors such as electromagnetic shaker and PVDF patch, 21 impact hammer and accelerometer, 22 loudspeaker and laser sensor, 23 electromagnetic shaker and macro-fiber composite patch, 24 etc., respectively. Later on, the free vibration analysis of torus using Galerkin method was performed to demonstrate the importance of geometric non-linearity and the direct action of pressure force on the torus, by comparing the results from different approximate shell theories.…”

Section: Introductionmentioning

confidence: 99%

Parameter estimation of butyl rubber aided with dynamic mechanical analysis for numerical modelling of an air-inflated torus and experimental validation using 3D-laser Doppler vibrometer

Sharma

Bhattacharya

2019

Journal of Low Frequency Noise, Vibration and Active Control

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Over the few decades, there has been an exponential growth in the application of inflated torus system in the field of space deployable antenna design, solar propulsion, and aerodynamic deceleration system. However, such a system is inherently susceptible to mechanical vibration and hence requires precise modal analysis to produce stable inflatable structures. This paper summarizes all the necessary steps to be followed for dynamic analysis of inflatable structures. With this objective, a butyl rubber-based inflated torus system with dynamic material properties has been considered in this work. On performing mechanical tests of the rubber sample, properties like Prony series parameters, complex modulus, and damping values were obtained. Using laser Doppler vibrometry, the modal behavior of a butyl rubberbased air-inflated torus with free-free boundary condition was studied. The results achieved from experimental modal analysis and simulation involving fluid-structure interaction were found to be in close proximity. It is envisaged that the test template integrated with numerical validation can lay the foundation for designing complex inflatable torus structures.

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Dynamic Testing of an Inflatable, Self-Supporting, Unpressurized Thin-Film Torus

Cited by 16 publications

References 6 publications

Dynamic Testing of a Pre-stretched Flexible Tube for Identifying the Factors Affecting Modal Parameter Estimation

Dynamic Testing of a Pre-stretched Flexible Tube for Identifying the Factors Affecting Modal Parameter Estimation

Global Static Testing and Model Validation of Stiffened Thin-Film Polyimide Panels

Parameter estimation of butyl rubber aided with dynamic mechanical analysis for numerical modelling of an air-inflated torus and experimental validation using 3D-laser Doppler vibrometer

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