1,721,532 research outputs found
A robust integration-algorithm for a finite-strain shape-memory-alloy superelastic model
No full textA viscoplastic constitutive equation bounded between two generalized plasticity models
No full textThe present work addresses a new rate-dependent inelastic constitutive equation, whose response Is always bounded between two distinct rate-independent generalized plasticity models. Main features of the proposed model are the following: (1) it approaches the two rate-independent generalized plasticity models for the case of fast and slow loading conditions, respectively; (2) it properly describes loading-unloading-reloading conditions for any loading rate; (3) it reproduces the experimentally observed difference between the dynamic and the static yielding conditions. These are all properties to be taken into account to obtain an accurate modeling for many different classes of materials, such as metals, polymers, geomaterials, shape-memory alloys. Both the time-continuous and the time-discrete version of the model are discussed. Moreover, a solution algorithmic within a return map setting as well as the form of the discrete consistent tangent tensor are addressed. Finally, some numerical simulations illustrate the performance of the proposed constitutive model
Three-dimensional modeling of shape-memory materials
No full textESOMAT 2000, Fifth European Conference on Martensitic Transformations and Shape Memory Alloys, Como, Settembre 200
Augmented Lagrangian finite-elements for plate contact problems
No full textThe present work investigates the unilateral frictionless contact between a plate and a rigid obstacle. Two sets of problems are studied: a plate constrained through unilateral edge supports and a plate seating in its undeformed configuration at a given distance from a rigid support. The attention is concentrated on two augmented Lagrangian formulations. The algorithmic implementation within a finite‐element scheme is presented and discussed. The importance of using appropriate plate elements for the discretization of the structure is stressed. New gap elements compatible with a robust plate element are derived. Computational aspects are emphasized. A simple and effective numerical integration for the determination of the gap stiffnesses in partial contact with the support is proposed. Numerical results are carried out and compared with analytical solutions. The convergence to the solution of the perfectly constrained problem is numerically investigated. The inadequacy of the penalty method and the satisfactory performance obtained from only one augmented Lagrangian procedure are emphasized
Shape Memory Alloys: Material Modeling and Device Finite Element Simulations
No full textThe use of shape memory alloys (SMA) in an increasing number of applications in many fields of engineering, such as biomedical engineering, is leading to a growing interest toward an exhaustive modeling of their macroscopic behavior in order to construct reliable simulation tools for SMA devices. In this paper we review a robust three-dimensional model able to reproduce both pseudo-elastic and shape-memory behaviors and we report numerical studies where it is used for the simulation of SMA-based biomedical devices
On the enhanced strain technique for elasticity problems
No full textThe enhanced strain technique is considered in the context of incompressible elasticity problems. A new triangular element is proposed and proved to be convergent and stable when applied to linear analysis. Moreover, a model problem arising from large deformations is presented. Such a model is used to develop some theoretical considerations about the use of enhanced strain methods in nonlinear elasticity
3D printing: Clinical applications in orthopaedics and traumatology
No full textAdvances in image processing have led to the clinical use of 3D printing technology, giving the surgeon a realistic physical model of the anatomy upon which he or she will operate.Relying on CT images, the surgeon creates a virtual 3D model of the target anatomy from a series of bi-dimensional images, translating the information contained in CT images into a more usable format.3D printed models can play a central role in surgical planning and in the training of novice surgeons, as well as reducing the rate of re-operation
Partial selective reduced integration schemes and kinematically linked interpolations for plate bending problems
No full textA One-Dimensional Model Describing Stress-Induced Solid Phase Transformation with Residual Plasticity
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