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Civil-Comp Proceedings
ISSN 1759-3433 CCP: 77
PROCEEDINGS OF THE NINTH INTERNATIONAL CONFERENCE ON CIVIL AND STRUCTURAL ENGINEERING COMPUTING Edited by: B.H.V. Topping
Paper 31
Numerical Evaluation of Required Ductility and Load Bearing Capacity for Aluminium Alloy Continuous Beams M. Manganiello+, G. De Matteis*, R. Landolfo+ and F.M. Mazzolani*
+Department of Design, Rehabilitation and Control of Architectural Structures, University of Chieti-Pescara "G. d'Annunzio", Pescara, Italy
Full Bibliographic Reference for this paper
M. Manganiello, G. De Matteis, R. Landolfo, F.M. Mazzolani, "Numerical Evaluation of Required Ductility and Load Bearing Capacity for Aluminium Alloy Continuous Beams", in B.H.V. Topping, (Editor), "Proceedings of the Ninth International Conference on Civil and Structural Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 31, 2003. doi:10.4203/ccp.77.31
Keywords: plastic analysis, aluminium alloys, ductility, rotational capacity, strain hardening, internal forces redistribution.
Summary
Since the fifties, several authors have pointed out that the most economical and
rational structural design can be achieved using plastic analysis methods. In fact,
although linear elasticity theory may be appropriate for the computation of stresses
and strains under working loads, it is relatively meaningless as a measure of the
structural collapse. On the basis of such a consideration, plastic analysis methods,
able to define the resources of a system beyond the elastic range, were formulated
for civil structures [1].
In case of structures constituted by elastic-perfectly-plastic material, at the collapse
(when finite deformations of at least a part of the structure can occur without any
change in the loads) the internal bending moment distribution remains constant as
the structures deform. If the characteristics of the bending moment distribution at
collapse are defined, the classical theorems of limit analysis can be applied [2].
The main advantage of this methodology of analysis is its relative simplicity. In fact,
a rigorous method of analysis of structures loaded beyond the elastic limit should be
based on an incremental procedure by using a discretized model. However, such an
approach would be excessively burdensome and not compatible with practical
applications. For this reason, simpler methods, based on the concept of concentrated
plasticity are commonly adopted for the collapse analysis of structures. These
methods, which are tie tightly to the hypothesis of elastic-perfectly-plastic material,
have shown a satisfying precision in the prediction of the bearing capacity of steel
structures. In fact, in this case the material ductility allows the full development of
the plastic mechanism and the
In this paper, the results of an extensive numerical analysis devoted to the evaluation
of the inelastic behaviour of aluminium alloy beams are presented. For simple
structural systems as continuous beams, which are representative of the structural
applications of aluminium alloys, the flexural ductilities (available and required),
which must be compared when plastic analysis is carried out, are evaluated. The
parametric analysis is performed by using a numerical model implemented in the
implicit FE code ABAQUS/Standard [6] and calibrated against experimental tests.
The obtained results have allowed, on the hand an assessment of the influence of
mechanical (strain hardening) and geometrical (shape factor and flexural continuity)
parameters on the required rotational capacity and, on the other hand, a comparison
with the available rotational capacity depending on the material ductility.
On the basis of this results, a stress multiplier ( References
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