Selective mass scaling for explicit finite element analyses

2005 ◽  
Vol 63 (10) ◽  
pp. 1436-1445 ◽  
Author(s):  
Lars Olovsson ◽  
Kjell Simonsson ◽  
Mattias Unosson
Keyword(s):  
Finite Element ◽  
Finite Element Analyses ◽  
Explicit Finite Element ◽  
Mass Scaling

scholarly journals An Efficient and General Finite Element Model for Double-Sided Incremental Forming

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Newell Moser ◽  
David Pritchet ◽  
Huaqing Ren ◽  
Kornel F. Ehmann ◽  
Jian Cao
Keyword(s):  
Finite Element ◽  
Incremental Forming ◽  
Mesh Size ◽  
Element Model ◽  
Explicit Finite Element ◽  
Fully Integrated ◽  
Shell Elements ◽  
Mass Scaling ◽  
Element Simulation ◽  
Element Type

Double-sided incremental forming (DSIF) is a subcategory of general incremental sheet forming (ISF), and uses tools above and below a sheet of metal to squeeze and bend the material into freeform geometries. Due to the relatively slow nature of the DSIF process and the necessity to capture through-thickness mechanics, typical finite element simulations require weeks or even months to finish. In this study, an explicit finite element simulation framework was developed in LS-DYNA using fully integrated shell elements in an effort to lower the typical simulation time while still capturing the mechanics of DSIF. The tool speed, mesh size, element type, and amount of mass scaling were each varied in order to achieve a fast simulation with minimal sacrifice regarding accuracy. Using 8 CPUs, the finalized DSIF model simulated a funnel toolpath in just one day. Experimental strains, forces, and overall geometry were used to verify the simulation. While the simulation forces tended to be high, the trends were still well captured by the simulation model. The thickness and in-plane strains were found to be in good agreement with the experiments.

scholarly journals Simulating Extraocular Muscle Dynamics. A Comparison between Dynamic Implicit and Explicit Finite Element Methods

Mathematics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1024
Author(s):  
Jorge Grasa ◽  
Begoña Calvo
Keyword(s):  
Finite Element ◽  
Time Integration ◽  
Biological Tissues ◽  
Computational Time ◽  
Range Of Movement ◽  
Explicit Finite Element ◽  
Mass Scaling ◽  
Muscle Dynamics ◽  
Important Amount ◽  
Implicit And Explicit

The finite element method has been widely used to investigate the mechanical behavior of biological tissues. When analyzing these particular materials subjected to dynamic requests, time integration algorithms should be considered to incorporate the inertial effects. These algorithms can be classified as implicit or explicit. Although both algorithms have been used in different scenarios, a comparative study of the outcomes of both methods is important to determine the performance of a model used to simulate the active contraction of the skeletal muscle tissue. In this work, dynamic implicit and dynamic explicit solutions are presented for the movement of the eye ball induced by the extraocular muscles. Aspects such as stability, computational time and the influence of mass-scaling for the explicit formulation were assessed using ABAQUS software. Both strategies produced similar results regarding range of movement of the eye ball, total deformation and kinetic energy. Using the implicit dynamic formulation, an important amount of computational time reduction is achieved. Although mass-scaling can reduce the simulation time, the dynamic contraction of the muscle is drastically altered.

Survivability of Railroad Tank Car Top Fittings in Rollover Scenario Derailments

2010 ◽  
Author(s):  
Robert S. Trent ◽  
Anand Prabhakaran ◽  
Francisco Gonza´lez ◽  
Vinaya Sharma ◽  
Srinivas Chitti
Keyword(s):  
Finite Element ◽  
Impact Energy ◽  
Longitudinal Velocity ◽  
Nonlinear Material ◽  
Protective Structure ◽  
Finite Element Analyses ◽  
Explicit Finite Element ◽  
Damage And Failure ◽  
Concrete Barrier ◽  
Validation Testing

Railroad tank car top fittings are susceptible to damage and failure in rollover derailments, which might result in release of hazardous material lading to the environment. In this paper, we propose and analyze five protective structure concepts designed to eliminate or reduce damage to these top fittings in a rollover derailment, using explicit finite element analyses incorporating nonlinear material and geometry models. Three different rollover scenarios are studied; a nominal rollover, a more severe rollover with greater impact energy, and a rollover combined with longitudinal velocity, with the tank car impacting a concrete barrier. The results from these analyses as well as plans for validation testing are presented in the paper.

Prediction of Tread Pattern Wear by an Explicit Finite Element Model3

2007 ◽  
Vol 35 (4) ◽  
pp. 276-299 ◽  
Author(s):  
J. C. Cho ◽  
B. C. Jung
Keyword(s):  
Finite Element ◽  
Wear Rate ◽  
Tangential Stress ◽  
Rate Equation ◽  
Constitutive Equations ◽  
Slip Velocity ◽  
Test Results ◽  
Explicit Finite Element ◽  
Driving Condition ◽  
Driving Conditions

Abstract Tread pattern wear is predicted by using an explicit finite element model (FEM) and compared with the indoor drum test results under a set of actual driving conditions. One pattern is used to determine the wear rate equation, which is composed of slip velocity and tangential stress under a single driving condition. Two other patterns with the same size (225/45ZR17) and profile are used to be simulated and compared with the indoor wear test results under the actual driving conditions. As a study on the rubber wear rate equation, trial wear rates are assumed by several constitutive equations and each trial wear rate is integrated along time to yield the total accumulated wear under a selected single cornering condition. The trial constitutive equations are defined by independently varying each exponent of slip velocity and tangential stress. The integrated results are compared with the indoor test results, and the best matching constitutive equation for wear is selected for the following wear simulation of two other patterns under actual driving conditions. Tens of thousands of driving conditions of a tire are categorized into a small number of simplified conditions by a suggested simplification procedure which considers the driving condition frequency and weighting function. Both of these simplified conditions and the original actual conditions are tested on the indoor drum test machines. The two results can be regarded to be in good agreement if the deviation that exists in the data is mainly due to the difference in the test velocity. Therefore, the simplification procedure is justified. By applying the selected wear rate equation and the simplified driving conditions to the explicit FEM simulation, the simulated wear results for the two patterns show good match with the actual indoor wear results.

Tire Cornering Simulation Using an Explicit Finite Element Analysis Code

1998 ◽  
Vol 26 (2) ◽  
pp. 109-119 ◽  
Author(s):  
M. Koishi ◽  
K. Kabe ◽  
M. Shiratori
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Test System ◽  
Experimental Results ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Explicit Finite Element Analysis ◽  
Element Method

Abstract The finite element method has been used widely in tire engineering. Most tire simulations using the finite element method are static analyses, because tires are very complex nonlinear structures. Recently, transient phenomena have been studied with explicit finite element analysis codes. In this paper, the authors demonstrate the feasibility of tire cornering simulation using an explicit finite element code, PAM-SHOCK. First, we propose the cornering simulation using the explicit finite element analysis code. To demonstrate the efficiency of the proposed simulation, computed cornering forces for a 175SR14 tire are compared with experimental results from an MTS Flat-Trac Tire Test System. The computed cornering forces agree well with experimental results. After that, parametric studies are conducted by using the proposed simulation.

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