Year

1982

Degree Name

Doctor of Philosophy

Department

Department of Civil and Mining Engineering

Abstract

This dissertation presents the results of theoretical investigations of the large deflection elastic analyses of plates and multiplate systems arid elasto-plastic analysis of plates. The finite strip method has been extended to the geometrically nonlinear analyses of plates (with initial imperfections),and folded plate structures including box-girders. Also included are the finite strip solutions ot material and combined material and geometrically nonlinear plate problems. The loading considered includes uniformly distributed, patch type and concentrated loads acting transversely.

The formulations of the geometric and combined nonlintar problems are based on the theory of minimum total potential energy. For the sake of convenience independent formulations have been made to deal with individual nonlinearities( i.e. geometric and/or material).

in the large deflection elastic analysis of plate and plated structures, both incremental and combined incremental and iterative solution procedures have been adopted. The iterative procedure has been implemented in some special cases. The salient feature of this analysis is characterised by the use of Marguerre's shallow shell theory in order to analyse plates with or without initial imperfections. Thus, a plate can be simulated by a number of shallow shell strips and the adopted procedure, unlike others, does not require displacement transformations between the local and global axes, which would otherwise be necessary for large deformations or possible initial imperfections.

The large deflection elastoplastic analysis is based on von Mise's yield criterion and the solution procedure employs a piece-wise linear incremental approach.

A number of examples related to plates and plated structures have been solved in order to prove the validity of the proposed finite strip method in the area of geometric nonlinearity while its applicability to combined nonlinear problems has been tested by solving some plate bending problems. The variation of deflections and stresses have been plotted against load and compared with existing solutions where available. Elasto-plastic analysis has been carried out on a number of simply supported and fixed plates and the progressive yielding of the structures, over the volume has been traced and the collapse load has been predicted.

The problems have been formulated in matrix algebra and solved on the Wollongong University UNIVAC-1106 Computer System. The plotting of graphs and elasto-plastic maps have been prepared on a Tektronix 4025 and Calcomp plotters using graphics packages implemented on the UNIVAC Computer. The main part of this dissertation has been prepared on the UNIVAC Computer and processed by DOC Processor which provides the output in a Thesis Format. There is one limitation in the computer processed output that, there will be some unwanted spaces near the regions where equations are required to be inserted externally. Figures and tables are located at the end of Chapter 9.

Comments

Accompanying microfiche can be consulted with the hard copy of the thesis in the Archives Collection, call no. is 624.17765/3

Share

COinS