Mesh independent modelling of tensile failure in laminates using mixed-time integration in explicit analysis

2021 ◽  
pp. 108113
Author(s):  
Jagan Selvaraj ◽  
Luiz F. Kawashita ◽  
Stephen R. Hallett
Keyword(s):  
Time Integration ◽  
Tensile Failure ◽  
Explicit Analysis

scholarly journals NUMERICAL SIMULATION OF A MASSIVE IMPACTOR FALLING ONTO A REINFORCED CONCRETE BEAM

2020 ◽  
Vol 82 (1) ◽  
pp. 5-15
Author(s):  
S.M. Gertsik ◽  
Yu.V. Novozhilov
Keyword(s):  
Finite Elements ◽  
Concrete Beam ◽  
Time Integration ◽  
Volumetric Strain ◽  
Failure Criteria ◽  
Tensile Failure ◽  
Low Velocity Impact ◽  
Isotropic Hardening ◽  
Elastoplastic Material ◽  
Low Velocity

The paper presents the results of numerically modeling the dynamics of a concrete beam reinforced by longitudinal rods and transversal frames of rods under the effect of a falling massive impactor. The dynamic behavior of the material of concrete is described using the Holmquist - Johnson - Cook model. The reinforcement of the beam is modeled by beam elements, using the bilinear model of elastoplastic material with isotropic hardening. Binding between the reinforcement and concrete is described by introducing additional kinematic equations that couple degrees of freedom of the related nods of the beam and volumetric finite elements. The mathematical model makes it possible to introduce additional failure criteria to predict propagation of tensile cracking. Pressure lower than the minimal one (failure only in the tension zone) and volumetric strain higher than the threshold value are taken as a criterion of tensile failure. Failure is modeled by removing elements from the computational pattern, when the above failure criteria are satisfied. The effect of accounting for failure on the response of the beam is analyzed. Numerical modeling is done using the finite-element method with explicit time integration in the LOGOS and LS-DYNA systems. Concrete is modeled using linear four-node finite elements with one integration point. The impactor is modeled as an absolutely solid body with a detailed description of the impacting end. The obtained results are compared with experimental data. It is demonstrated that the Holmquist - Johnson - Cook material model developed for analyzing high-velocity impacts can also be applied to problems of low-velocity impact.

Tensile Failure of 55-Nitinol Wire

1975 ◽  
Vol 33 ◽  
pp. 46-47
Author(s):  
F. I. Grace
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Stoichiometric Composition ◽  
Tensile Failure ◽  
Initial State ◽  
Initial Shape ◽  
Nitinol Wire ◽  
Cscl Type ◽  
Shear Transformation

An interest in NiTi alloys with near stoichiometric composition (55 NiTi) has intensified since they were found to exhibit a unique mechanical shape memory effect at the Naval Ordnance Laboratory some twelve years ago (thus refered to as NITINOL alloys). Since then, the microstructural mechanisms associated with the shape memory effect have been investigated and several interesting engineering applications have appeared.The shape memory effect implies that the alloy deformed from an initial shape will spontaneously return to that initial state upon heating. This behavior is reported to be related to a diffusionless shear transformation which takes place between similar but slightly different CsCl type structures.

Advances and Challenges in Time-Integration of PDE's

2003 ◽  
Author(s):  
David Gottlieb ◽  
Jan Hesthaven
Keyword(s):  
Time Integration

Inverse agreement in Hungarian

2017 ◽  
Author(s):  
András Bárány
Keyword(s):  
First Person ◽  
Personal Pronouns ◽  
Second Person ◽  
Morphological Effect ◽  
Object A ◽  
Feature Sets ◽  
Explicit Analysis ◽  
The Subject ◽  
Agreement Morphology ◽  
Object Agreement

This chapter turns to object agreement with personal pronouns in Hungarian. Pronouns are interesting because they do not always trigger agreement with the verb: first person objects never trigger object agreement (morphology), and second person pronouns only do with first person singular subjects. It is proposed that the distribution of object agreement is a morphological effect and argues that all personal pronouns do in fact trigger agreement, but agreement is not always spelled out. This means that Hungarian has an inverse agreement system, where the spell-out of agreement is determined by the relative person feature (or person feature sets) of the subject and the object. A formally explicit analysis of the syntax and the morphological spell-out of agreement is provided.

scholarly journals A Fully Implicit Finite Volume Scheme for a Seawater Intrusion Problem in Coastal Aquifers

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1639
Author(s):  
Abdelkrim Aharmouch ◽  
Brahim Amaziane ◽  
Mustapha El Ossmani ◽  
Khadija Talali
Keyword(s):  
Finite Volume ◽  
Coastal Aquifers ◽  
Nonlinear Partial Differential Equations ◽  
Time Integration ◽  
Mass Conservation ◽  
Coupled System ◽  
Finite Volume Scheme ◽  
Time Step ◽  
Volume Scheme ◽  
Fully Implicit

We present a numerical framework for efficiently simulating seawater flow in coastal aquifers using a finite volume method. The mathematical model consists of coupled and nonlinear partial differential equations. Difficulties arise from the nonlinear structure of the system and the complexity of natural fields, which results in complex aquifer geometries and heterogeneity in the hydraulic parameters. When numerically solving such a model, due to the mentioned feature, attempts to explicitly perform the time integration result in an excessively restricted stability condition on time step. An implicit method, which calculates the flow dynamics at each time step, is needed to overcome the stability problem of the time integration and mass conservation. A fully implicit finite volume scheme is developed to discretize the coupled system that allows the use of much longer time steps than explicit schemes. We have developed and implemented this scheme in a new module in the context of the open source platform DuMu X . The accuracy and effectiveness of this new module are demonstrated through numerical investigation for simulating the displacement of the sharp interface between saltwater and freshwater in groundwater flow. Lastly, numerical results of a realistic test case are presented to prove the efficiency and the performance of the method.

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