scholarly journals A plane-stress plasticity model for masonry for the explicit finite element time integration scheme

2020 ◽  
Vol 53 (3) ◽  
pp. 240-258
Author(s):  
Oliver Gustav Sebastian Lundqvist ◽  
Michael Chauhan
Keyword(s):  
Finite Element ◽  
Biaxial Loading ◽  
Time Integration ◽  
Material Model ◽  
Integration Scheme ◽  
Plasticity Model ◽  
Explicit Finite Element ◽  
Time Integration Scheme ◽  
Uniaxial And Biaxial Loading ◽  
Good Agreement

Masonry is a composite material and can be considered anisotropic on a macroscopic scale, i.e., masonry exhibits different properties in different directions, both in the elastic and inelastic range. Like other quasi-brittle materials, masonry exhibits softening and hardening behavior after failure for compression and tension. In this paper a smeared continuum plasticity model of masonry is presented as well as it numerical implementation in an explicit finite element time integration scheme, as such a material model does not exist for a commercial explicit finite element solver. The implementation is done by writing a user-defined material model (VUMAT) as a Fortran subroutine in the commercial software ABAQUS Explicit. The material model is tested both in uniaxial and biaxial loading against similar tests from earlier research. The results show good agreement with earlier research.

Transonic Flow Computations in Cascades Using Finite Element Method

1981 ◽  
Vol 103 (4) ◽  
pp. 657-664 ◽  
Author(s):  
H. U. Akay ◽  
A. Ecer
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Transonic Flow ◽  
Method Development ◽  
Time Integration ◽  
Integration Scheme ◽  
Complex Flow ◽  
Time Integration Scheme ◽  
Naca 0012 ◽  
Element Method

Analysis of transonic flow through a cascade of airfoils is investigated using the finite element method. Development of a computational grid suitable for complex flow structures and different types of boundary conditions is presented. An efficient pseudo-time integration scheme is developed for the solution of equations. Modeling of the shock and the convergence characteristics of the developed scheme are discussed. Numerical results include a 45 deg staggered cascade of NACA 0012 airfoils with inlet flow Mach number of 0.8 and angles of attack 1, 0, and −1 deg.

Time Integration of Impact Phenomena in Solid Mechanics: A One-Dimensional Model Problem

1996 ◽  
Author(s):  
V. Chawla ◽  
T. A. Laursen
Keyword(s):  
Finite Element ◽  
Solid Mechanics ◽  
Exact Analytical Solution ◽  
Time Integration ◽  
Dynamic Contact ◽  
Momentum Conservation ◽  
Integration Scheme ◽  
Mass System ◽  
Element Discretization ◽  
Time Integration Scheme

Abstract 1D impact between two identical bars is modeled as a simple spring-mass system as would be generated by a finite element discretization. Some commonly used time integrators are applied to the system to demonstrate defects in the numerical solution as compared to the exact analytical solution. Using energy conservation as the criterion for stability, a new time integration scheme is proposed that imposes a persistency condition for dynamic contact. Finite element simulation with Lagrange multipliers for enforcing the contact constraints shows exact energy and momentum conservation.

Numerical and Experimental Examination of Ballistic System Subjected to IED Explosion

2014 ◽  
Vol 224 ◽  
pp. 276-285 ◽  
Author(s):  
Paweł Dybcio ◽  
Wiesław Barnat
Keyword(s):  
Blast Wave ◽  
Experimental Validation ◽  
Computational Analysis ◽  
Time Integration ◽  
Numerical Data ◽  
Integration Scheme ◽  
Standard Level ◽  
Time Integration Scheme ◽  
Level 1 ◽  
Good Agreement

This article presents results of experimental validation of complex phenomenon of blast wave and fragment impact on protective panel. Protective panel was made of HTK900K steel and Dyneema HB50 polyethylene. Standard level 1 IED surrogate was used. Test was conducted with regards to NATO STANAG 4569 and NATO AEP 55 standardizations. Computational analysis was performed using LS-DYNA code using explicit time integration scheme. Properties of steel, polyethylene and glue were obtained during laboratory tests. Steel was modeled using simplified Johnson-Cook model whereas polyethylene was modeled as composite material. Both blast wave and fragment impact was implemented in simulation. Good agreement between experimental and numerical data was obtained.

A Newly Developed Algorithm for Treating the Coupled Dynamic Response of Robotic Fixtureless Assembly

1996 ◽  
Author(s):  
Genady Shagal ◽  
Shaker A. Meguid
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Equations Of Motion ◽  
Time Integration ◽  
Integration Scheme ◽  
The Finite Element Method ◽  
Coupled Equations ◽  
Time Integration Scheme ◽  
Implicit Approach ◽  
Cooperating Robots

Abstract The coupled dynamic response of two cooperating robots handling two flexible payloads for the purpose of fixtureless assembly and manufacturing is treated using a new algorithm. In this algorithm, the equations describing the dynamics of the system are obtained using Lagrange’s method for the rigid robot links and the finite element method for the flexible payloads. A new time integration scheme is developed to treat the coupled equations of motion of the rigid links for a given displacement of the flexible payloads. The finite element equations of the flexible payloads are then treated using an implicit approach. The new algorithm was verified using simplified examples and was later used to examine the dynamic response of two cooperating robot arms manipulating flexible payloads which are typical of the automotive industry.

Dynamic Behaviour of Delaminated Composite Plate Under Blast Loading

2017 ◽  
Author(s):  
Chetan Kumar Hirwani ◽  
Subrata Kumar Panda ◽  
Siba Sankar Mahapatra ◽  
Sanjib Kumar Mandal ◽  
Apurba Kumar De
Keyword(s):  
Finite Element ◽  
Composite Plate ◽  
Degrees Of Freedom ◽  
Dynamic Behaviour ◽  
Time Integration ◽  
Blast Loading ◽  
Element Model ◽  
Continuity Condition ◽  
Integration Scheme ◽  
Time Integration Scheme

In the present article, the dynamic behaviour of the delaminated composite plate subjected to blast loading has been investigated. For the investigation, a general finite element model using higher-order mid-plane kinematics has been developed. The model has been discretised using nine noded isoparametric Lagrangian elements having nine degrees of freedom at each node. The continuity in the laminated and delaminated section has been established using the intermittent continuity condition. The final governing equation has been solved by applying Newmark’s time integration scheme in conjunction with finite element steps. Further, the said responses have been evaluated by developing an in-house MATLAB code based on the proposed model. In order to illustrate the consistency and accuracy of the present model, convergence and comparison study has been conducted i.e. the responses are evaluated for different mesh sizes and compared them with those of responses of earlier published literature. Finally, various examples have been solved to illustrate the influence of the size and position of debonding, side to thickness ratio, aspect ratio and end condition on the dynamic response of composite structure and discussed in detail.

scholarly journals Transient Wave Propagation Dynamics with Edge-Based Smoothed Finite Element Method and Bathe Time Integration Technique

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Yingbin Chai ◽  
Yongou Zhang
Keyword(s):  
Finite Element ◽  
Wave Propagation ◽  
Time Integration ◽  
Numerical Dispersion ◽  
Integration Scheme ◽  
Transient Wave ◽  
Time Integration Scheme ◽  
Smoothed Finite Element Method ◽  
Transient Wave Propagation ◽  
Edge Based

In this work, the edge-based smoothed finite element method (ES-FEM) is incorporated with the Bathe time integration scheme to solve the transient wave propagation problems. The edge-based gradient smoothing technique (GST) can properly soften the “overly soft” system matrices from the standard finite element approach; then, the spatial numerical dispersion error of the calculated solutions for wave problems can be significantly reduced. To effectively solve the transient wave propagation problems, the Bathe time integration scheme is employed to perform the involved time integration. Due to the appropriate “numerical dissipation effects” from the Bathe time integration method, the spurious oscillations in the relatively large wave numbers (high frequencies) can be effectively suppressed; then, the temporal numerical dispersion error in the calculated solutions can also be notably controlled. A number of supporting numerical examples are considered to examine the capabilities of the present approach. The numerical results show that ES-FEM works very well with the Bathe time integration technique, and much more numerical solutions can be reached for solving transient wave propagation problems compared to the standard FEM.

Modeling of 3D Magnetostrictive Systems with Application to Galfenol and Terfenol-D Actuators

2012 ◽  
Vol 77 ◽  
pp. 11-28
Author(s):  
Marcelo J. Dapino ◽  
Suryarghya Chakrabarti
Keyword(s):  
Finite Element ◽  
Time Integration ◽  
Three Dimensional ◽  
Nonlinear Dynamic System ◽  
Element Model ◽  
Implicit Time ◽  
Integration Scheme ◽  
Modeling Framework ◽  
Time Integration Scheme ◽  
Parametric Analyses

This work presents a unified approach to model three dimensional magnetostrictive transducers. Generalized procedures are developed for incorporating nonlinear coupled constitutive behavior of magnetostrictive materials into an electro-magneto-mechanical finite element modeling framework. The finite element model is based on weak forms of Maxwell's equations for electromagnetics and Navier's equations for mechanical systems. An implicit time integration scheme is implemented to obtain nonlinear dynamic system responses. The model is implemented into a finite element (FE) solver and applied to two case studies, a Galfenol unimorph actuator and a magnetohydraulic Terfenol-D actuator for active engine mounts. Model results are compared with experiments, and parametric analyses are conducted which provide guidelines for optimization of actuator design.

scholarly journals An improved finite element model for vibration and control simulation of smart composite structures with embedded piezoelectric sensor and actuator

2001 ◽  
Author(s):  
◽  
Marino Kekana
Keyword(s):  
Finite Element ◽  
Active Control ◽  
Potential Field ◽  
Time Integration ◽  
Piezoelectric Sensor ◽  
Control Model ◽  
Integration Scheme ◽  
Time Integration Scheme ◽  
Piezoelectric Control ◽  
And Control

This thesis details a study conducted to investigate the dynamic stability of an existing active control model (ACFl) of a composite structure embedded with a piezoelectric sensor and actuator for the purpose of vibration measurement and control. Criteria for stability are established based on the second method of Lyapunov which considers the energy of the system. Results show that ACFl is asymptotically stable although piezoelectric control effects persist when the feedback gain is set to zero. Meanwhile, it is required that there should be no control effects occurring through the piezoelectric actuator when the gain is set to zero. In this study, a new active control model (ACF2) is developed to satisfy the stability criteria, which satisfies the requirement of no piezoelectric control effects when the gain is set to zero. In ACF2 - as well as ACFl - the displacement and potential fields are discretised using the finite element method. In light of the locking phenomena associated with discrete displacements - which is expected to be pronounced in the case of discrete potentials due to their element geometry, ACF2-mixed is developed. ACF2 and ACF2-mixed control methodologies are similar except that in ACF2 both the displacement and potential field are discretised whereas in ACF2-mixed, only the displacement field is discretised and the potential field is continuous. Consequent to ACF2 and ACF2-mixed, stability analysis of the resulting time integration scheme is investigated as well. The results show that the damping forces due to the piezoelectric effect do not add energy to the structure. Hence, asymptotic stability is achieved. The time integration scheme yielded a small error, consistent with the literature. Numerical results revealed that ACFl exhibits a high degree of locking which is relaxed in ACF2 whereas ACF2-mixed exhibits envisaged results when compared with the other two models. Therefore, the ACF2 and ACF2-mixed will provide engineers with an alternative simulation model to solve actively controlled vibration problems hitherto.

scholarly journals Validation of a New Finite Element for Incremental Forming Simulation Using a Dynamic Explicit Approach

2007 ◽  
Vol 344 ◽  
pp. 495-502 ◽  
Author(s):  
Christophe Henrard ◽  
Chantal Bouffioux ◽  
Laurent Duchêne ◽  
Joost R. Duflou ◽  
Anne Marie Habraken
Keyword(s):  
Finite Element ◽  
Incremental Forming ◽  
Time Integration ◽  
Computation Time ◽  
New Method ◽  
Integration Scheme ◽  
Forming Process ◽  
Forming Simulation ◽  
Time Integration Scheme ◽  
Mesh Density

A new method for modeling the contact between the tool and the metal sheet for the incremental forming process was developed based on a dynamic explicit time integration scheme. The main advantage of this method is that it uses the actual contact location instead of fixed positions, e.g. integration or nodal points. The purpose of this article is to compare the efficiency of the new method, as far as accuracy and computation time are concerned, with finite element simulations using a classic static implicit approach. In addition, a sensitivity analysis of the mesh density will show that bigger elements can be used with the new method compared to those used in classic simulations.

Sign in / Sign up

Export Citation Format

Share Document