Emeritus Professor Hoshyar Nooshin started his academic career in May 1963 when he joined the Department of Civil Engineering of the Battersea College of Advanced Technology (predecessor of the University of Surrey) as an Assistant Lecturer. Subsequently, he held the positions of Lecturer, Reader and Professor, and carried on with his academic activities after retirement, as a part-time Professor. He became an Emeritus Professor in 2008, but he continues to be active in teaching and research. Currently, he is involved in the supervision of 4 research students. Also, the number of PhD Degrees awarded to his research students in the past is 36, with the main area of his research being the computer aided design of spatial structures.
Professor Nooshin was born in 1934 in Tehran, Iran. He received his first degree in Civil Engineering from the Faculty of Engineering of University of Tehran. Subsequently, he obtained a postgraduate degree of DIC in Structural Engineering from Imperial College, UK, and a Degree of PhD in the field of Spatial Structures from the University of London.
Professor Nooshin was the Director of the Space Structures Research Centre of the University of Surrey for 28 years. He was the Chief Editor of the International Journal of Space Structures for 20 years. Also, he was a member of the executive council of the International Association for Shell and Spatial Structures (IASS), as well as a member of the Advisory Board of this association for a number of years.
He is the originator of the concepts of formex algebra and has many publications in this area. His interests are mainly in the fields of structural engineering, mathematics and philosophy.
" What are the metric properties for a lattice structure and how can these be evaluated?
" What is the definition of regularity for lattice structures and how can this be quantified?
" How could the regularity of a lattice structure be improved?
The Author is an architect and structural engineer who has been involved in the design and construction of lattice spatial structures for 20 years. The experience of the actual construction over the years has shown that there are advantages in keeping the number of different types of structural components small. In another front, the study of regularity of forms for lattice structures may involve the ?visual aspects?, ?arrangements of elements? or ?structural components?. The first two aspects are subjective matters and the latter one, that is the focus of the present work, is an objective matter. The present research shows that the metric properties of structural forms are fundamental for the study of component regularity. There are considerable benefits in terms of the construction of structures which have a high degree of regular components. The benefits include savings in time and cost of construction, as well as a reduction in probability of having a wrong arrangement during assembly. In this sense, the present work could be considered as a research of fundamental importance which provides a basis for the knowledge in this field. Most of the examples in the Thesis are single layer lattice structures with straight elements and further research on other types of lattice structures is recommended.
This thesis consists of six chapters, the first of which entitled ?Introduction? provides background information about the research and discusses the research aims. Chapter 2 on the ?Literature Review? concerns the few available publications relevant to the research. The third chapter entitled ?Metric Properties? defines a number of geometrical parameters which are being used to generate the geometrical information. Also, the mathematics involved for the necessary calculations are discussed. This chapter is a major contribution of the thesis and to the available knowledge in terms of introduction a set of well defined geometrical parameters for design and construction of lattice spatial structures. Chapter 4 is dedicated to discussion of different aspects of ?Regularity? of lattice structures. To begin with, the idea of regularity is elaborated upon and then the concept of ?regularity indicators? are discussed. These indicators help to quantify regularity of components. Here again, this chapter presents a novel idea in the field of lattice spatial structures. Another major contribution of this thesis to the general knowledge is Chapter 5 entitled ?Sphere Packing?. This is a particular technique for configuration processing developed by the Author to improve the member length regularity of lattice structures. An example of the application of the technique for configuration processing of spherical domes is also discussed in details. Moreover, a comparison on the variation of the member lengths of different dome configurations is discussed which shows that around 50% of the members
Dynamic behaviour of single-layer lattice domes is complicated and fundamentally differs from conventional building structures. Their response to dynamic excitation is characterised by the contribution of several vibration modes throughout a wide range of frequencies. Furthermore, due to large deformations associated with a possible development of plasticity within the structure, seismic response of single-layer lattice domes to severe earthquakes is normally highly nonlinear. So far, in the absence of a practical equivalent static seismic loading scheme, realistic seismic response evaluation of single-layer lattice domes still relies on nonlinear dynamic time-history analysis.
Herein, a new analytical method for estimating the nonlinear seismic response of different types of single-layer lattice domes is presented, as the main contribution of this research. The method is based on ?Modal Pushover Analysis? (MPA) concept which conveniently accounts for the participation of higher vibration modes in the seismic response, and is consistent with the inherent dynamic characteristics of single-layer lattice domes. The efficiency and accuracy of the proposed method is verified through comparison between the MPA results and those obtained from a full geometrically and materially nonlinear time-history dynamic analysis. It is shown that the proposed method yields accurate results for all types of single-layer lattice domes with different geometrical properties, and effectively removes the necessity of performing nonlinear time-history earthquake response analysis.
Moreover, dynamic characteristics of single-layer lattice domes is sensitive to the geometrical particulars of the structural system. Accordingly, the importance of various geometrical particulars of single-layer lattice domes on their dynamic characteristics has been carried out by means of parametric studies, as the other contribution of this research. The particulars studied include ?span?, ?rise-to-span-ratio?, ?pattern of the configuration?, and ?relative stiffness of the supports?. It is concluded that ?rise-to-span-ratio? and ?relative stiffness of the supports? are two important parameters which significantly influence the dynamic behaviour, the effects of other properties on dynamic characteristics of single-layer lattice domes are less important.