Please use this identifier to cite or link to this item: http://localhost:8081/jspui/handle/123456789/17501
Title: DYNAMIC ANALYSIS OF WRINKLING MEMBRANE STRUCTURE FOR SPACE APPLICATION
Authors: Patel, Vishal Kalubhai
Keywords: Architecture;Membrane Structures;Sails;Windmills
Issue Date: Jun-2013
Publisher: I I T ROORKEE
Abstract: In the field of Engineering and Architecture, Membrane structures play a vital role in many ways. Examples include textile covers and roofs, aircraft and space structures, parachutes, automobile airbags, sails, windmills, human tissues and long span structures. They are typically built with very light materials which are optimally used. These structures are characterized because they are only subjected to in-plane axial forces. A membrane is essentially a thin shell with no flexural stiffness. Consequently a membrane cannot resist any compression at all. However, membrane theory accounts for tension and compression stresses, and the need for a computational procedure that takes into account tension stresses only is needed. In membrane theory only the in-plane stress resultants are taken into account. The position of points on the two-dimensional surface in the Euclidean space gives the deformation state for a membrane. A numerical solution for membranes may be found using the finite element method. In this the modal analysis for the predicating the behavior of inflatable membrane structure of general shape with a thickness in millimeter using the various smart material which optimally within structural member subjected to various pre-stressed rather than bending or moments. A numerical solution for membranes may also be found using the finite element method. In this, flat thin membranes is chosen and analyzed its behavioral effect using different thickness of the material and different pre-stresses and compare the frequency, Eigen values and generalized mass, corresponding to mode of frequency. This analysis makes more effective in future to selects the geometry of the membrane in the space technology. Vibration analysis of arbitrary shape of membrane is also done using a finite element package, ABAQUS. The analysis shows good agreement between finite element and analytical solutions. Currently, there are a growing number of space missions that consider using membrane structures with a wide variety of shapes and sizes. These deployable structures consist of thin polymer films that offer a wider range of packaging configurations than structures with traditional deployment mechanisms. The material constitutive behavior and the analytical tools to analyze them are required to make advances in building cheaper, lighter and more reliable structures. A wrinkling algorithm is described to simulate realistic wrinkles on the membrane for large computational overheads. The membrane has very little in-plane deformations and most of the deformations come from buckling. The formulation of the deformed area due to symmetric loading uses the modulated method to ensure or characterize the user defined wrinkle pattern which is based on deformation of individual triangle. The methodology facilitates the use of small in-plane deformation stiffness's and a coarse mesh for the numerical simulation. This approach has been validated using the numerical simulation considering the different symmetric loading condition on the particular triangular shaped element. Moreover, the ability to design wrinkles (even on generalized deformable models) n-iakes this method more versatile. The minimal mass (ultra-light weight) and high packaging efficiency (stowage volume) are the most important factors which are associated with the space technology and hence become more attractive traits for getting larger bandwidth satellites on-orbit. Now days. maintaining the surface shape of pretension membrane to the instrument precision become a more challenging problem. Hence, membrane reflectors are getting more and more attentions for mission architectures that need extremely large in space deployable antennas. The finite-element (FE) investigation of a rectangular shape flat thin membrane using PVDF (PolyVinylidene Fluoride) piezo-actuated material as an actuators/sensor is presented. The passive effect of PVDF on the dynamics of an inflatable space-based rectangular shaped structure has been studied and trend in natural frequencies for various patch areas and thickness has been explored. Investigation shows that rather than using the various numbers of patches to the practical system for controlling their vibration behaviour, the single patch with the appropriate thickness can easily control the desire vibration behaviour. 1-lence the discrete sensor/actuators devices are to be preferred to realize lower weight and effective control authority for the modest values of actuators voltages for active vibration control of practical structures.
URI: http://localhost:8081/jspui/handle/123456789/17501
metadata.dc.type: Other
Appears in Collections:MASTERS' THESES (MIED)

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