Behaviour And Design Of Aluminium Alloy Structural Elements

This dissertation, "Behaviour and Design of Aluminium Alloy Structural Elements" by Meini, Su, 蘇玫妮, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Aluminium alloys are nonlinear metallic materials with continuous stress-strain curves that are not well represented by the simplified elastic, perfectly plastic material model used in most existing design specifications. The aims of this study are to develop a more efficient design method for aluminium alloy structures by rationally exploiting strain hardening. The key components of this study include laboratory testing, numerical modelling and development of design guidance for aluminium alloy structures. As part of the present study, the experimental programme included tests on 11 stub columns, 40 simply supported beams, 46 continuous beams and corresponding tensile coupon tests. Numerical investigations of aluminium alloy simply supported beams and continuous beams were also conducted. The validated finite element models were used for extensive parametric studies, generating 96 results for beams under three-point bending, 96 under four-point bending and 210 for continuous beams. The experiments and numerical simulations have shown the following key features of the inelastic behaviour of aluminium alloy structural elements: (1) the significance of strain hardening, indicated by the ultimate stress over the yield stress, could be up to 50%; (2) non-slender section capacities could be generally up to 40% higher than the yield limits in compression, and 50% greater than the plastic moments in bending; (3) the experimental and numerical ultimate loads of continuous beams on non-slender sections go beyond the calculated loads corresponding to the occurrence of the first hinge by more than 10%. Previous experimental data on aluminium alloy stub columns and simply supported beams were also collected. These collected test data were used together with the newly generated experimental and numerical results obtained from this study, totalling about 900 data, to assess the design predictions of the American, Australian/New Zealand and European specifications. On average, the existing design methods under-estimated the capacity of aluminium alloy stub columns by around 15% 22%, simply supported beams by around 18% 40% and continuous beams by around 27% 50%. Existing section classification limits in Eurocode 9 (2007) were also assessed, and while they were found to be safe, some improved limits were proposed. The combined experimental and numerical results were used to develop and calibrate a new design method, termed the continuous strength method (CSM). Two key components of the CSM - a base curve and a bi-linear material model for aluminium alloys have been proposed in this study. Global plastic analysis allowing for moment redistribution has also been adopted in the CSM. Unlike current practices, the CSM has the merits of adopting the continuous treatment for the cross-section deformation response, rationally exploiting the available capacity beyond the yield limit and reasonably allowing for redistributing the internal forces. The capacity predictions of aluminium alloy structural members have been improved by more than 30% using the CSM. Reliability analyses have also been performed to assess the reliability level of different design methods according to the American Institute of Steel Construction (2010) and European Standard EN1990 (2002) approaches. The CSM has been shown to be safe, efficient and consistent for aluminium alloy structural members. DOI: 10.5353/th_b5328036 Subjects:

The subject of the book is the design of aluminium alloys structures. The subject is treated from different points of view, like technology, theory, codification and applications. Aluminium alloys are successfully employed in the transportation industry; A parallel trend has been observed in the last decades in civil engineering structures, where aluminium alloys compete with steel (long-span roofing, bridges, hydraulic structures, offshore superstructures). This volume collects the lectures of out-standing international experts, who are all involved in the codification activity of Eurocode 9 on Aluminium Structural Design. It illustrates, with particular reference to the fields of transportation and civil engineering, the basic design principles from the material properties and the technological aspects of their application, to the evaluation of the resistance of the structural elements (member and plates) under static, dynamic and fatigue loading conditions.

"This book discusses the use of aluminium in structural and non-structural applications and provides an introduction to designing structures made from aluminium or aluminium alloy elements. It provides a complete ready reference to the material properties and behavior of aluminium, and its use in structural design.

This dissertation, "Behaviour and Design of Aluminum Alloy Structural Members" by Jihua, Zhu, 朱繼華, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled BEHAVIOUR AND DESIGN OF ALUMINIUM ALLOY STRUCTURAL MEMBERS Submitted by ZHU JIHUA for the Degree of Doctor of Philosophy at The University of Hong Kong in September 2006 The behaviour and design of aluminum alloy structural members are investigated in this study. The research focused on aluminum columns, beams, and beam-columns of square, rectangular and circular hollow sections. Both experimental and numerical investigations were performed and reported. The effects of transverse welds on column strengths were also investigated. Design rules for aluminum columns with and without transverse welds were proposed. The experimental study included column, beam and beam-column tests. The test specimens were fabricated by extrusion using normal strength aluminum alloy 6063- T5 and high strength aluminum alloy 6061-T6. Both the non-welded and welded material properties were obtained from different coupon tests. The local and overall geometric imperfections were measured. The test program for fixed-ended columns was conducted on 70 column specimens that included 50 columns with both ends welded to aluminum end plates and 20 columns without welding of end plates. The column length ranged from 300 to 3000 mm in order to obtain a column curve for each test series. The test program for beams and beam-columns included 6 pure bending tests and 44 beam-column tests of five different cross-sections. Pure bending tests were conducted for each test series to determine the bending capacities of the specimens. The beam-column specimens were compressed between pinned ends at different eccentricities in order to obtain an interaction curve for each series of test. The test strengths were compared with the design strengths calculated using the American, Australian/New Zealand and European specifications for aluminum structures. A numerical investigation of fixed-ended aluminum alloy tubular columns of square, rectangular and circular hollow sections is also presented. An accurate finite element model was developed. The initial local and overall geometric imperfections were incorporated in the model. The non-welded and welded material nonlinearities were considered in the analysis. The welded columns were modeled by dividing the columns into different portions along the column length, so that the heat-affected zone softening at both ends of the welded columns was included in the simulation. The nonlinear finite element model was verified against the experimental results. It is shown that the calibrated model provided accurate predictions of the experimental loads and failure modes of the tested columns. Hence, the model was used for an extensive parametric study of cross-section geometry. The parametric study included 248 column specimens that covered a wide range of column length and cross-section dimensions. The heat-affected zone softening factors have been proposed for square and circular hollow sections based on the results obtained from the parametric study. Design approaches for aluminum alloy tubular columns with and without transverse welds were proposed. Column strengths predicted by the finite element analysis were compared with the design strengths calculated using the current American, Australian/New Zealand and European specifications for aluminum structures. In addition, the direct strength method, which was originally developed fo

The aim of this book is to provide a practical and simplified guide to the design of structural elements in aluminium, using the British Standards, especially BS 8118 'Structural use of aluminium', as its basis. The book is intended to give a broad introduction to the subject; there are more advanced books treating the research and theoretical aspects of aluminium, its alloys, temper designations, but none that consider the design of aluminium structures using BS 8118. The book is written as a text for undergraduate and postgraduate students of building, civil and structural engineering, especially those studying aluminium design; as familiarization material for consultant, contracting engineers and technicians, who design in aluminium or who check design calculations; and as a reference for those working on aluminium structures in the aerospace, offshore and marine industries.