1,721,150 research outputs found
Performance of Confinement on Masonry
No full textMost of the confinement models for masonry, empirical in nature, have been calibrated against their own sets of experimental data or they are simply derived from concrete. Masonry confinement is still highly correlated to concrete confinement, so that extensive experimental and theoretical studies are still needed to assess more reliable mechanical models of masonry confinement.
Due to the extremely large variability in masonry performance, general equations cannot always be provided that are equally suitable for every masonry type. In this paper a novel approach is proposed, based on a mechanically based strength theory. In this way it is possible to differentiate various masonries based on the mechanical properties of the masonry as a whole.
The proposed model is able to account also for non uniform confining stress fields, i.e. as it is found in non circular cross sections, so that the key innovative aspect is the different contribution of confining stress field not equal in the two transverse directions x and y.
The effect of confinement is evaluated explicitly considering a plasticity model under triaxial compression. According to this model it is possible to assess the sensitivity of the confinement performance as a function of characteristic mechanical properties of masonry, and in particular those that potentially provide differences in the behaviour of different masonry materials
Structural optimization of free-form reciprocal structures
No full textThis paper presents an optimization algorithm for the design of structurally efficient free-form reciprocal structures. Because of the geometric complexity of reciprocal structures, only a few structural studies have been carried out so far, and we have a limited knowledge of the relation between geometry and structural behaviour in reciprocal structures. This study takes advantage of the preceding work carried by the author on the Reciprocalizer, a software tool for the generation of reciprocal geometries. The Reciprocalizer has been included into a structural optimization algorithm for the generation of structurally efficient free-form reciprocal structures
Accurate Finite Element Modelling of Chipboard Single-Stud Floor Panels subjected to Dynamic Loads
No full textIn multi-storey buildings, the use of lightweight material has many advantages. The low weight, the low energy consumption and the sustainability of the material are some attractive benefits from using lightweight materials. Compared with heavier structures i.e. concrete the challenge in constructing a building compliant with building codes vis-a-vis the propagation of sound and vibrations within the structure is a challenge. Focusing on junctions in a multi-storey lightweight buildings, a modular finite element model is developed to be used for analyses of vibration transmission in lightweight buildings subjected to different types of loads
Knowledge-Based Assistance for the Analysis, Design and Optimization of Civil Structures
No full textAn on-going project is described which has as its goal
the development of an Al-based software package to assist
in structural analysis and optimal design while explicitly
treating uncertain risks. For preliminary design
of a proposed structural system, it is desirable to search
through a large design space to evaluate possible choices
on the basis of multiple criteria, so that the most promising
choice can be selected for detailed design. The goal of
this project is to increase efficiency, fully integrate, and partially automate the design/build decision process by
using AI- based methodologies such as knowledge-base expert
systems, object-oriented programming, fuzzy reliability,
multi-criteria decision theory and stochastic optimization.
The methodology developed in this 11tudy allows
the user to rapidly evaluate and improve a proposed
conceptual design while taking into account the major
factors affecting decisions related to design, construction,
and operation in the presence of uncertain risk. These factors
include not only structural engineering criteria, but
also social, political, legal, and economic considerations.
The first stage of this on-going project involved the development
of a working prototype of an interfaced suite
of knowledge-base expert systems consisting of analysis,
design and optimization tools with user interactive features.
The second stage of the project involves extending
the capabilities of the software tools and introducing au
explicit treatment of risk
Accuracy of Dynamic and Acoustic Analysis of Lightweight Panel Structures:a comparison of ABAQUS and ANSYS
No full textCurrently there is an increasing focus on the transmission of low frequency sound in buildings, as sources such as road and air traffic or even home theatre subwoofers become part of everyday life for many people. Hence, development of efficient and accurate methods for prediction of sound in such buildings is important. In the lowfrequency range, prediction of sound and vibration in building structures may be achieved by finite-element analysis (FEA). The aim of this paper is to compare the two commercial codes ABAQUS and ANSYS for FEA of an acoustic-structural coupling in a timber lightweight panel structure. For this purpose, modal analyses are carried out employing a fully coupled model of sound waves within an acoustic medium and vibrations in the structural part. The study concerns the frequency range 50–250 Hz
An Efficient Implementation of Non-Linear Limit State Analysis Based on Lower-Bound Solutions
No full textLimit State analysis has been used in design for decades e.g. the yield line theory for concrete slabs or slip line solutions in geotechnics. In engineering practice manual methods have been dominating but in recent years the interest in numerical methods has been increasing. In this respect it is mandatory to formulate the methods using the well-known finite element concept in order to interface with other types of analysis
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