Search results for "Finite Element"
showing 10 items of 892 documents
Competition between the buckling-driven delamination and wrinkling in compressed thin coatings
2012
Abstract The competition between two common failure modes of a thin coating under in-plane compression, the surface wrinkling and the buckling-driven delamination, is studied to assess the critical strain when the mechanical instability may occur at given geometrical and material parameters. A buckling map is constructed based on results of a finite element analysis, which relates the critical applied strain for the onset of instability to the interface adhesion and elastic properties of materials. An approximate scaling relation is derived for the energy release rate of buckling-driven delamination of a coating deposited on a compliant substrate.
INVESTIGATIONS OF STRAIN AND STRESS STATE AND CAPACITY IN SHORT CYLINDRICAL SHELLS UNDER INTERNAL PRESSURE
1989
In the paper it has been assumed that a triaxial stress and strain state occurs in a shell. The finite element method was used and owing to that digitization of the problem was possible. Such digitization was necessary for a numerical analysis of the moment stress state in the shell. On the ground of physical relations of the Prandtl-Reuss plastic flow theory an algorithm was formulated. The algorithm was a basis of calculating strains and stresses and determining capacity in a short cylindrical shell with rigid bottoms. The shell was subject to internal pressure. Experiments were carried out, as well. The results obtained with: equations of the membraneous shell theory, using plastic flow …
Finite element analysis in vertebrate palaeontology
2002
The Finite Element Analysis (FEA) is a numerical method which allows to analyse the static and dynamic behaviour of complex structures. A structure is substituted by a model consisting of a number of small, well-defined elements, each interconnected by nodes. Within the element attributes and material properties, the model can be exposed to static or dynamic loads. The displacements of the structure as the reaction to its loadings are calculated. Other data such as stress or strain at localized points in the structure are derived from these displacements. Originally developed for engineering, FEA soon was introduced to human medicine by modelling the behaviour of bone, teeth, cartilage and …
Recent advances in local probe techniques in corrosion research – Analysis of the role of stress on pitting sensitivity
2007
Local probe techniques have been largely applied to predict the spatial distribution of the electrochemical reactions and to quantify the corrosion rate. These local probe techniques are now being developed to capture the temporal information, in-situ and in real-time. Nevertheless only few works have been devoted to investigate with these local probes the role of stress on pitting sensitivity on passive materials. In this paper, a part of the most recent studies based on combination of local electrochemical measurements with finite element mapping of surface stress gradients are reported illustrating the role of inclusions under straining and the mechanical effect of surface preparation on…
Stress fields in general composite laminates
1996
A direct approach is employed to obtain a general boundary integral formulation for the analysis of composite laminates subjected to uniform axial strain. The integral equations governing the problem are directly deduced from the reciprocity theorem, employing the generalized orthotropic elasticity fundamental solutions expressly inferred. The solution is achieved by the boundary element method, which gives, once the traction-free boundary conditions and the interfacial continuity conditions are enforced, a linear system of algebraic equations. The formulation does not present restrictions with regard to the laminate stacking sequence and it does not require any aprioristic assumption. The …
FEM analysis of push-out test response of Hybrid Steel Trussed Concrete Beams (HSTCBs)
2015
Abstract Aiming to investigate the steel truss–concrete stress transfer mechanism in Hybrid Steel Trussed–Concrete Beams (HSTCBs), a three-dimensional (3D) nonlinear Finite Element (FE) model is developed. The constitutive relationship of the steel composing the plates and the rebars is modeled by means of a quadri-linear law, while the concrete behavior is defined by means of a Concrete Damaged Plasticity (CDP) model, suitable for modeling concrete and brittle materials. Two main failure mechanisms are considered, namely the tensile cracking and the compressive crushing. In order to accurately grasp the complicate dowel and bond phenomena arising at the steel–concrete interface, a 3D solid…
Numerical assessment of the thermomechanical behaviour of the DEMO Water-Cooled Lithium Lead inboard blanket equatorial module
2018
Abstract Within the framework of EUROfusion R&D activity, a research campaign has been carried out at the University of Palermo, in close cooperation with ENEA labs, in order to assess the thermo-mechanical performances of the DEMO Water-Cooled Lithium Lead (WCLL) inboard blanket equatorial module, whether properly integrated within its whole inboard segment. In particular, a detailed 3D model of this segment, including all the other modules, the back-supporting structure and the attachment system, has been considered in order to realistically simulate the boundary conditions affecting the equatorial module behaviour. The study has been focused on the investigation of the module thermo-mech…
Thermomechanical analysis supporting the preliminary engineering design of DONES target assembly
2018
Abstract The design of the Demo Oriented NEutron Source (DONES) is the main objective of the Work Package Early Neutron Source (WPENS) of EUROfusion Power Plant Physics and Technology (PPPT) programme. DONES is an IFMIF-based neutron source with the goal of testing and qualifying candidate materials to be used in DEMO and future fusion power plants. In the framework of these activities, a research campaign has been carried out at the University of Palermo, in close cooperation with ENEA labs, in order to assess the thermomechanical performances of the DONES target system, endowed with an integrated Target Assembly (TA) when it undergoes the thermomechanical loads typical of its nominal oper…
Theoretical and Experimental Model for the Analysis of a Cardan Cross
2015
The work presents the aproach of initial moddeling and calculus in order to prepare an finite element investigation of the cardan transmission joint. For this, it is necessary to develop a flexible informational system that would connect the constructive design of cardan transmissions to the technological design within a unitary structure. Due to the typodimensional diversity of cardan transmissions, the design and manufacturing of the various components for a certain application domain (medical aparature, dental and agricultural machines, lifting and transportation machines etc.) has been typified. In order to study the problems that occur in the practice of using cardan transmissions, the…
Structural analysis of the back supporting structure of the DEMO WCLL outboard blanket
2017
Abstract Within the framework of EUROfusion R&D activities an intense research campaign has been carried out at the University of Palermo, in close cooperation with ENEA Brasimone, in order to investigate the thermo-mechanical performances of the outboard segment Back-Supporting Structure (BSS) of the DEMO Water-Cooled Lithium Lead breeding blanket (WCLL). In particular, the configuration of the outboard segment BSS, purposely set-up by the WCLL project team during 2015 according to the blanket “multi-module system” concept, has been taken into account in order to study its steady state thermo-mechanical behaviour, paying attention to the simulation of both modules-BSS and BSS-vacuum vessel…