1,721,020 research outputs found
A novel approach to model differential settlements and crack patterns in masonry structures
No full textThe present paper introduces a novel methodology for accurately modelling differential settlements beneath the foundations of masonry structures and the resulting crack patterns. In contrast to standard strategies, which typically impose predefined settlements at the structure's base, the proposed approach directly accounts for the soil–structure interaction by coupling the mechanical responses of masonry and soil. Specifically, the mechanical behaviour of the masonry is accurately modelled using an elastic no-tension approach, while the soil is represented as an elastic half-plane. The solution to the coupled mechanical problem, satisfying both equilibrium and compatibility conditions, is obtained through an iterative optimisation-based procedure. Several 2D numerical applications, considering different geometries and loading conditions, are provided to demonstrate the proposed procedure's effectiveness and performance and highlight its potential
Limit analysis of masonry structures: upper bound approach based on homogenization and local mesh refinement
No full textWe present an upper bound limit analysis tool for plane stress problems in masonry. A given masonry construction is discretized into planar rigid-perfectly plastic finite elements, whose kinematics is described by rigid body velocities and plastic strain rates. To properly represent the collapse behaviour of the heterogeneous masonry material, the plastic strain rates must follow the homogenized kinematic conditions derived for running bond masonry textures. For a given load configuration, a rigid-plastic limit analysis problem can be defined and solved to find a mechanism and an associated collapse load. Local mesh refinement is finally applied to optimize the representation of the mechanism and minimize the collapse load
Elastostatic analysis by BEM-NURBS approach.
No full textIn the present paper the Boundary Element Method is developed in the framework of the Computer Aided Design softwares in two-dimensional elastostatics. The B-splines, commonly used to reproduce the geometry of the model, are here adopted to model the field variables and, thus, to solve the structural model under static loads
Reliability-based bottom-up manufacturing cost optimisation for composite aircraft structures
No full textA novel methodology is presented for the reliability-based manufacturing cost optimisation of composite aircraft structures. A comprehensive bottom-up costing approach is employed, enabling precise manufacturing cost estimation in terms of material, machine, labour, tooling, and indirect costs. This approach splits the manufacturing process into many individual activities, which can be combined in many different ways, allowing the proposed optimisation methodology to be applied to a wide range of composite aircraft structures. A genetic algorithm (GA) is coupled with a deep neural network (DNN) to efficiently determine the optimal composite ply stacking sequence for every part of an assembled structure. A numerical example featuring a composite-stiffened aircraft fuselage panel is investigated. The reliability of the panel is measured in terms of its buckling resistance, and its manufacturing cost is estimated based on the individual costs of over 20 activities. The labour times for each activity were estimated based on data collected from an aerospace company specialising in the manufacture of advanced composite aircraft structures. Results indicate that material, machine, labour, and tool costs can vary significantly depending on the level of structural reliability required, demonstrating the importance of accounting for non-material costs when designing composite aircraft structures
Flaw identification in elastic solids; theory and experiments
No full textIn this work the problem of identification flaws or voids in elastic solids is addressed both from a theoretical and experimental point of view. Following a so called “inverse procedure”, which is based on appropriately devised experiments and a particular bounding of the strain energy, a “gap functional” for flaw identification is propose
On Boundary Integral approach for the Identification of Structural defect: Theory and experiments
No full textBuckling analysis of Levy-type orthotropic stiffened plate and shell based on different strain-displacement models
No full textIn the present work a model able to predict the buckling behavior of thin, orthotropic, stiffened plates and shells subject to axial compression is proposed. In the context of the Kirchhoff-Love plate theory and making use of different strain-displacement models - namely the von Kármán model, the Koiter-Sanders shell model, an Enhanced von Kármán model and a spurious model
commonly adopted in literature - the equilibrium equations have been solved by the Levy-type approach. The results obtained highlight the influence of each non linear strain-displacement term and show that the von Kármán model can noticeably overestimate the buckling load when the critical mode involves significant in-plane displacements
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