Stressed-skin plastic pyramids as elements of double layer grids

This thesis is concerned with the structural behaviour of thin walled plastics pyramids which form a shear resisting medium between the upper and lower elements of double layer grids. The several aspects of the work are described under separate headings in seven chapters. In Chapter 1 the various ty...

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Main Author: Robak, Daniel
Published: University of Surrey 1970
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624
Online Access:https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.751760
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spelling ndltd-bl.uk-oai-ethos.bl.uk-7517602019-03-05T15:41:41ZStressed-skin plastic pyramids as elements of double layer gridsRobak, Daniel1970This thesis is concerned with the structural behaviour of thin walled plastics pyramids which form a shear resisting medium between the upper and lower elements of double layer grids. The several aspects of the work are described under separate headings in seven chapters. In Chapter 1 the various types of construction are discussed and the properties of the most important structural plastics materials reviewed. Chapters 2, 3 and 4 contain a description of the experimental work undertaken on single pyramids and on a roof model consisting of sixteen pyramids. The behaviour of pyramids both before and after initial buckling is investigated and conclusions are drawn whenever appropriate. Chapters 5, 6 and 7 are devoted to the theoretical treatment of stressed-skin pyramids and comparison of the observed quantities with those obtained from calculations. The theoretical part is of a fundamental nature and constitutes the author's own and original contribution. The stress distribution is determined by superimposing on the stresses existing in an infinite pyramid a linear combination of corrective solutions, each satisfying the boundary conditions at the inclined edges of the pyramid walls. By this means any type of simple or mixed boundary conditions at the base and cap can be satisfied. The displacements are derived by introducing displacement functions from which both the stress and displacement components can be determined. A finite difference approach is used for calculating buckling loads, while the ultimate load-carrying capacity is assessed by modifying the known semi-empirical formulae for rectangular plates. The theoretical part includes computer programs, which are essential for the understanding of the numerical analysis. The results for typical cases are reproduced in Appendices A and B. Design aspects and practical considerations have been taken into account throughout the work.624University of Surreyhttps://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.751760http://epubs.surrey.ac.uk/847946/Electronic Thesis or Dissertation
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topic 624
spellingShingle 624
Robak, Daniel
Stressed-skin plastic pyramids as elements of double layer grids
description This thesis is concerned with the structural behaviour of thin walled plastics pyramids which form a shear resisting medium between the upper and lower elements of double layer grids. The several aspects of the work are described under separate headings in seven chapters. In Chapter 1 the various types of construction are discussed and the properties of the most important structural plastics materials reviewed. Chapters 2, 3 and 4 contain a description of the experimental work undertaken on single pyramids and on a roof model consisting of sixteen pyramids. The behaviour of pyramids both before and after initial buckling is investigated and conclusions are drawn whenever appropriate. Chapters 5, 6 and 7 are devoted to the theoretical treatment of stressed-skin pyramids and comparison of the observed quantities with those obtained from calculations. The theoretical part is of a fundamental nature and constitutes the author's own and original contribution. The stress distribution is determined by superimposing on the stresses existing in an infinite pyramid a linear combination of corrective solutions, each satisfying the boundary conditions at the inclined edges of the pyramid walls. By this means any type of simple or mixed boundary conditions at the base and cap can be satisfied. The displacements are derived by introducing displacement functions from which both the stress and displacement components can be determined. A finite difference approach is used for calculating buckling loads, while the ultimate load-carrying capacity is assessed by modifying the known semi-empirical formulae for rectangular plates. The theoretical part includes computer programs, which are essential for the understanding of the numerical analysis. The results for typical cases are reproduced in Appendices A and B. Design aspects and practical considerations have been taken into account throughout the work.
author Robak, Daniel
author_facet Robak, Daniel
author_sort Robak, Daniel
title Stressed-skin plastic pyramids as elements of double layer grids
title_short Stressed-skin plastic pyramids as elements of double layer grids
title_full Stressed-skin plastic pyramids as elements of double layer grids
title_fullStr Stressed-skin plastic pyramids as elements of double layer grids
title_full_unstemmed Stressed-skin plastic pyramids as elements of double layer grids
title_sort stressed-skin plastic pyramids as elements of double layer grids
publisher University of Surrey
publishDate 1970
url https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.751760
work_keys_str_mv AT robakdaniel stressedskinplasticpyramidsaselementsofdoublelayergrids
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