-
Effects of Initial Geometrical Imperfection on Square Tube Collapse
Liang Xue, Zhongqin Lin, Zhengxu Jiang - Shanghai Jiao Tong University
-
Random geometric imperfections are natural in structures. The initial imperfections used to be
ignored in structure strength analysis and thus geometric-perfect models were used in most
case of numerical simulation. However, collapse of axially compressed square tubes is not
such a case. LS-DYNA is used to simulate the effects initial geometrical imperfection has on
square tube collapse. This study proves that dynamic progressive buckling of ...
-
Fan Blade Bird-Strike Analysis and Design
Thomas J. Vasko - Pratt & Whitney
-
Bird ingestion is a costly and difficult engine test to perform. It is also one of the most
challenging and complex analytical investigations in engine design. The capability to model
bird ingestion effects is, therefore, critical to the success of any competitive jet engine
program. LS-DYNA has been used in the design and analysis of fan blades for bird-strikes.
Descriptions of the bird and blade models used in the analyses along with the ...
-
Analysis of a Propane Tank Truck Impacting a Concrete Column Using LS-DYNA
Clayton F. Heberling - Pressure Sciences, Inc.
-
Pressure Sciences Inc. used LS-DYNA to model a propane tank truck colliding with a
concrete column. The analysis simulates an accident that occurred in 1994 in White Plains,
New York. Correlation between the accident and an LS-DYNA analysis of that crash is
described. The ultimate purpose of the analyses is to improve the crashworthiness of propane
semi-trailers.
To address the stiffening effect of the propane fluid, we correlated several ...
-
Comparison of Two Modeling Approaches for Thin-Plate Penetration Simulation
Norman F. Knight - Veridian-MRJ, USA
Navin Jaunky - Eagle Aeronautics, USA
Robin E. Lawson - FDC/NYMA, USA
Damodar R. Ambur - NASA Langley Research Center, USA
-
Modeling and simulation requirements for uncontained engine debris impact on fuselage
skins are described and assessed using the tied-nodes-with-failure (TNWF) approach and the
element-erosion (EE) approach for penetration simulation. The TNWF approach is based on
coincident nodes generated in selected regions of the target plate that are tied together using a
constraint relation and the target plate is modeled with shell elements. The EE ...
-
Making FEM Tire Model And Applying It For Durability Simulation
Masaki Shiraishi, Hiroshi Yoshinaga, Naoaki Iwasaki, Sumitomo Rubber Industries - LTD
Kimihiro Hayashi - The Japan Research Institute,Ltd
-
In recent years, CAE (Computer Aided Engineering) has become very popular for
effective development of many industrial products. In the development of automobile,
CAE has been applied in many fields. About endurance and fatigue analyses of
automobile, it is necessary to simulate the force by road input, and accurate tire model is
necessary for this. But the construction of tire is very complicated and its model is so
complicated that large ...
-
Accurate and Detailed LS-DYNA FE Models of the US- and EUROSID: A Review of the German FAT Project
Ulrich Franz, Oliver Graf - CAD-FEM GmbH, Grafing/ Munich, Germany
-
Finite element side impact dummy models of the USSID and EUROSID are of major interest
for industry, as more detailed models are required for better prediction capabilities, but still
efficiency has to be maintained to some degree. Both type of models, the so-called FAT-
USSID and FAT-EUROSID have been developed by CAD-FEM in cooperation with the
German Association for Automotive Research (FAT). The main objective was to achieve
highly ...
-
Study on the Effects of Numerical Parameters on the Precision of Springback Prediction
Zhongqin Lin, Gang Liu, Weili Xu, Youxia Bao - Shanghai Jiaotong University
-
Accurate prediction of springback is the precondition of controlling the springback. The
precision of springback prediction is affected by many parameters in both forming process and
springback process. The 2-D draw bending benchmark of NUMISHEET’93 is used as an
example to investigate the influencing of numerical parameters in LS-DYNA and LS-NIKE3D,
which includes solution approach, dynamic effect, number of the dies’ corner elements ...
-
ADAPTIVE FINITE ELEMENT SIMULATION OF SHEET METAL FORMING PROCESSES USING GRADIENT BASED INDICATORS
Ramin Moshfegh, Xiangdong Li, Larsgunnar Nilsson, Ramin Moshfegh -Linköping Institute of Technology
-
Two mesh refinement indicators based on the gradients of effective stresses (GSIG) and
effective plastic strains (GEPS), respectively, are proposed for adaptive finite element
analysis of the large deformation, quasi-static or dynamic response of shell structures.
The mesh refinement indicators are based on equi-distributing the variation of stresses or
plastic strains over the elements of the mesh. A program module is developed ...
-
Computer Simulation of Sheet Metal Forming and Drawbead Effects Using eta/DYNAFORM
Yinghong Peng, Zhaoyuan Wang, Xiongfei Yin, Xueyu Ruan - Shanghai Research Institute of Tool & Die
-
The kernel technology of a computer simulation system and the general procedure of
dynamic simulation in sheet metal forming are presented. As an example, processing
parameters of the experimental die of a car inner door panel were optimized with
eta/DYNAFORM software. The appropriate round corner of punch, BHF and the correct
layout of the drawbead were obtained.
-
Micromechanics Based Composite Material Model for Impact and Crashworthiness Explicit Finite Element Simulation
Ala Tabiei, Quing Chen - University of Cincinnati
-
A micro-mechanical model is developed for laminated composite materials and implemented
in the explicit finite element method. The objective of this study is to get an accurate and
simple micro-model, which can be used in the displacement-based nonlinear explicit finite
element code DYNA3D. The micro-mechanical model implemented in the explicit finite
element code can be used for simulating the behavior of composite structures under ...
-
USE OF LS-DYNA SHELL ELEMENTS IN THE ANALYSIS OF COMPOSITE PLATES WITH UNBALANCED AND UNSYMMETRIC LAYUPS
Saiphon Charoenphan, Lawrence C. Bank, Michael E. Plesha - University of Wisconsin-Madison
-
In order to obtain the desired coupling between deformation modes that can occur in
composite material plates having unbalanced and/or unsymmetric lamination schemes, the
appropriate shell element formulation must be selected from the available formulations in LS-
DYNA. An investigative study was conducted to determine which of the shell element
formulations in LS-DYNA 950 can be used for modeling such plates prior to performing in-
depth ...
-
Eight-Node Solid Element for Thick Shell Simulations
Yong Guo - Livermore Software Technology Corporation
-
An eight-node hexahedral solid element is incorporated into LS-DYNA to simulate thick
shell structure. The element formulations are derived in a corotational coordinate system
and the strain operator is calculated with a Taylor series expansion about the center of the
element. Special treatments are made on the dilatational strain component and shear strain
components to eliminate the volumetric and shear locking. The use of consistent ...
-
NEW FORMULATION FOR COMPOSITE SANDWICH SHELL FINITE ELEMENT
Romil Tanov, Ala Tabiei - University of Cincinnati
-
A new homogenization procedure for Finite Element (FE) analysis of
sandwich shells was recently developed and presented by the authors. To
the authors’ knowledge all present FE approaches to sandwich structures are
incorporated into the FE formulation on the element formulation level.
Unlike other formulations the present approach works on the constitutive
level. A homogenization of the sandwich shell is performed at each call of
the ...
-
A SIMPLE CORRECTION TO THE FIRST ORDER SHEAR DEFORMATION SHELL FINITE ELEMENT FORMULATIONS
Romil Tanov, Ala Tabiei - University of Cincinnati
-
The present work concentrates on the development of correct representation of
the transverse shear strains and stresses in Mindlin type displacement based
shell finite elements. The formulation utilizes the robust standard first order
shear deformation shell finite element for implementation of the proposed
representation of the transverse shear stresses and strains. In this manner the
need for the shear correction factor is eliminated. In ...
-
Teraflops and Beyond
Robert F. Lucas - Lawrence Berkeley National Laboratory
-
-
Anisotropic Behaviors and Its Application on Sheet Metal Stamping Processes
Weilong Hu, Jeanne He - ETA-Engineering Technology Associates, Inc.
-
Basic behaviors of anisotropic properties of materials, relating to sheet metal forming
processes, are discussed. The R-value is used to describe some forming problems including
wrinkles and thinning failures. According to the analysis results, to point out that the
anisotropic behaviors of materials affect the formability of blanks in some cases is very
serious. Finally, a numerical example is presented to discuss this property further.
-
The Effects of Forming and Parameter Mapping on Further Simulation
Brian Cowell, Anthony Kellicut, Adam Fisher - Tower Automotive
-
This paper describes the effects of forming simulation results on crash and durability
performance and the impact of the method of transferring results from one simulation to the
next. Forming simulation may not always result in a mesh that is ideally suited for static or
crash analysis. Tower Automotive has developed software to map forming simulation results
from the formed mesh to an entirely different LS-DYNA or NASTRAN mesh of the ...
-
Springback in High Strength Anisotropic Steel
Oladipo Onipede, Carlos J. Gomes - University of Pittsburgh
-
This paper presents the finite element analysis and results of springback in a U-shape cross
section made of high strength anisotropic steel. The results are compared with those obtained
from two isotropic materials that have the same yield stresses as those of the principal
directions of the anisotropic steel sheet. The principal directions are the directions of the sheet
that have the largest and smallest yield stresses respectively. The ...
-
Input Parameters for Metal Forming Simulation Using LS-DYNA
Bradley N. Maker, Xinhai Zhu - Livermore Software Technology Corporation
-
LS-DYNA has been widely used to study automotive crash. Default input parameters are
generally chosen to give efficient, accurate crash simulation results. These defaults are not
necessarily optimal for metal forming simulations. The following presents a standard
procedure for conducting metal forming simulations with LS-DYNA. Recommended input
parameters are identified in boldface type and included in boxed keyword input syntax for
quick ...
-
Finite Element Modeling of Co-Mingled Glass/Thermoplastic Fabrics for Low-Cost/High-Volume Composites Manufacturing
Patricia P. Buso, James A. Sherwood, Julie Chen - University of Massachusetts-Lowell
-
The stamping of co-mingled glass/thermoplastic textiles for manufacturing relatively low-
cost/high-volume structural composite automotive parts, e.g. truck beds and floor pans, is
extremely attractive. These textile materials have yarns comprised of polymer fibers
interwoven with the structural fibers, e.g. fiberglass. By heating the textiles in an oven, the
polymer fibers melt and infuse the yarn, thereby removing the need to apply the ...
-
Smooth Particle Hydrodynamics (SPH): A New Feature in LS-DYNA
Jean Luc LACOME - DYNALIS
-
A new particle element has been added to LS-DYNA. It is based on Smoothed Particle
Hydrodynamics theory. SPH is a meshless lagrangian numerical technique used to model
the fluid equations of motion. SPH has proved to be useful in certain class of problems
where large mesh distortions occur such as high velocity impact, crash simulations or
compressible fluid dynamics.
First, we introduce the basis principles of the SPH method. Then the ...
-
NEW NONLINEAR HIGHER ORDER SHEAR DEFORMATION SHELL ELEMENT FOR METAL FORMING AND CRASHWORTHINESS ANALYSIS: PART II. PERFORMANCE VALIDATION THROUGH STANDARD TESTS
Ala Tabiei, Romil Tanov - University of Cincinnati
-
This work presents the results from a set of verification shell problems used
to assess the performance of the higher order shear deformation shell
elements formulated in part I of the present study. The developed element
has been added to the element library of the nonlinear dynamic explicit
finite element code DYNA3D. Several standard verification test problems
are performed using the code DYNA3D with the developed shell element.
Results ...
-
NEW NONLINEAR HIGHER ORDER SHEAR DEFORMATION SHELL ELEMENT FOR METAL FORMING AND CRASHWORTHINESS ANALYSIS: PART I. FORMULATION AND FINITE ELEMENT EQUATIONS
Ala Tabiei, Romil Tanov - University of Cincinnati
-
This work presents the finite element formulation of a higher order shear
deformation shell element for nonlinear dynamic analysis with explicit time
integration scheme. A corotational approach is combined with the velocity
strain equations of a general third order theory in the formulation of a four-
noded quadrilateral element with selectively reduced integration. A bilinear
isoparametric formulation is utilized in the shell plane ...
-
Evaluation of Performance, Reliability, and Consistency of MPP Version of LS-DYNA
Cing-Dao Kan - The George Washington University
Yih-Yih Lin - Hewlett-Packard Company
-
This paper reports the on-going evaluation of the current distributed memory (MPP)
versions of LS-DYNA by using set of large size vehicle finite element models with
number of elements ranging from 200,000 to 380,000. The evaluation focuses on the
scaling performance, reliability, and consistency of the MPP code.
-
Message Passing and Advanced Computer Architectures
Brian Wainscott, Jason Wang - Livermore Software Technology Corporation
-
The emergence of distributed memory and cluster based computers is a recognized trend, with
obvious cost/performance benefits. Here we discuss strategies for efficient utilization of
these architectures on industrial problems. Results are presented which investigate the
communication bandwidth and latency requirements for production environments.
-
Design Optimization of the Beagle II Mars Lander Airbags Through Explicit Finite Element Analysis – An Update
Anthony P. Taylor - Irvin Aerospace Inc
-
The Beagle II Mars Lander is a portion of the European Space Agency (ESA) Mars Express
program. Irvin Aerospace Limited, on contract to Martin Baker Aerospace Ltd., will provide
the parachutes and airbags for the probe’s landing system. The purpose of the Beagle II
Lander is to deliver scientific equipment, which will perform atmospheric and soil
experiments focused on identifying signs of life on the Red Planet.
To reduce development ...
-
Shape Optimization Of Instrument Panel Components For Crashworthiness Using Distributed Computing
Alex Akkerman , Ravi Thyagarajan - Ford Motor Company,
Mike Burger, Nielen Stander - Livermore Software Technology Corp.,
Bob Kuhn, Hrabri Rajic - Kuck & Associates, Inc.
-
The ability to quickly design new vehicles with optimal crashworthiness is a goal of
automotive manufacturers. This paper takes steps towards that goal by automating manual
design iterations. The crashworthiness of an instrument panel was enhanced using LS-OPT
and LS-DYNA. It is shown that:
• LS-OPT can modify the shape of non-styled parts in the instrument panel in order to
• The design was generated several times faster than with ...
-
Global and Local Coupling Analysis for Small Components in Drop Simulation
Jason Wu - Motorola
-
The failure induced in radio/phone drop often associate with the damage of inside small
components or its tiny substructures. The difficulty to detect the failure in drop simulation is:
i) the right drop-induced shock at the components must come from the simulation at whole-
phone model; ii) the required output at the small components needs very fine local mesh,
which causes unbearable CPU cost and make the simulation impossible. ...
-
Preliminary Study of the Behavior of Composite Material Box Beams Subjected to Impact
Jason R. Smith, Lawrence C. Bank, Michael E. Plesha - University of Wisconsin-Madison
-
LS-DYNA 940.2 was used to study the response of composite box beams subjected to
oblique (or inclined) impacts by a rigid cylinder. The square cross-section composite beams
were 1000 mm long with 50 mm by 50 mm nominal cross-sectional dimensions. The rigid
cylinder had a 50 mm diameter and a 100 mm length and impacted the box beam on the top
panel. The composite box beam and the cylinder were modeled with 3 mm thick Belytschko-
Tsay shell ...
-
Implementation of Constitutive Equations for Viscoplasticity with Damage and Thermal Softening into the LS-DYNA Finite Element Code, with Application to Dynamic Fracture of Ring- Stiffened Welded Structures
Ricardo F. Moraes, David W. Nicholson - University of Central Florida
-
Constitutive equations for a viscoplastic model with damage and thermal softening are
implemented in the Finite Element (FE) code LS-DYNA using a User Defined Subroutine
UMAT. A modified Johnson-Cook constitutive model, UMAT 15, which accounts for strain rate
viscoplastic effects, is used. The Continuum Damage Mechanics (CDM) is based on Bonora
formulation (Bonora, 1997). The combined material model, named UMAT 41, is added to the
program ...
