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首页LS-DYNA 971 用户手册 - 关键功能与指南
LS-DYNA 971 用户手册 - 关键功能与指南
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"LS-DYNA 971用户手册第一卷"
LS-DYNA是一款强大的非线性有限元分析软件,常用于模拟复杂的动态事件,如碰撞、爆炸、结构变形等。971版本是该软件的一个特定版本,可能包含了当时最新的功能和改进。本手册是针对LS-DYNA关键词用户的专业指导文档,旨在帮助用户理解和应用软件的各种功能。
手册的发布日期为2007年5月,由Livermore Software Technology Corporation (LSTC)出版。LSTC是一家专注于提供高级工程仿真解决方案的公司,其总部位于美国加利福尼亚州利弗莫尔。此外,手册还提供了公司的联系方式,包括电话、传真、电子邮件地址以及网站,以便用户在遇到问题或需要支持时能与LSTC取得联系。
LS-DYNA软件的使用涉及许多专业领域,包括但不限于机械工程、航空航天、汽车工业和材料科学。手册中的内容可能涵盖了关键字输入、网格生成、材料模型、求解器设置、后处理以及各种物理现象的模拟方法。这些关键字是LS-DYNA的核心部分,它们允许用户通过简洁的命令行输入来定义问题的各个方面,如几何、边界条件、材料属性和加载工况。
请注意,LS-DYNA的使用需要一定的专业知识,因为它的功能非常强大且灵活。手册中的信息和示例主要用于说明性的目的,可能并未包含所有可能的应用或选项。LSTC明确声明,他们不对手册中的信息或使用软件产生的结果承担任何责任,这提示用户在实际应用中需要根据具体情况进行适当的判断和验证。
此外,LS-DYNA的商标,如LS-OPT和LS-PrePost,分别代表了LSTC的优化工具和前/后处理软件,这些工具通常与LS-DYNA一起使用,以完成完整的分析流程,从模型创建到结果分析。所有其他商标、产品名称和品牌名称属于各自的所有者。
LS-DYNA 971用户手册是理解并有效利用这款软件进行非线性动力学分析的重要资源。它不仅包含了技术细节,还可能提供了案例研究和实践指南,有助于用户提升在相关工程问题上的仿真能力。
TABLE OF CONTENTS
xvi LS-DYNA Version 971
APPENDIX J
INTERACTIVE GRAPHICS COMMANDS.................................................................................J.1
APPENDIX K
INTERACTIVE MATERIAL MODEL DRIVER ........................................................................K.1
INTRODUCTION.........................................................................................................................K.1
INPUT DEFINITION ...................................................................................................................K.1
INTERACTIVE DRIVER COMMANDS ....................................................................................K.3
APPENDIX L
VDA DATABASE........................................................................................................................ L.1
APPENDIX M
COMMANDS FOR TWO-DIMENSIONAL REZONING..........................................................M.1
REZONING COMMANDS BY FUNCTION..............................................................................M.2
APPENDIX N
RIGID BODY DUMMIES............................................................................................................N.1
APPENDIX O
LS-DYNA MPP USER GUIDE....................................................................................................O.1
APPENDIX P
IMPLICIT SOLVER..................................................................................................................... P.1
INTRODUCTION......................................................................................................................... P.1
SETTING UP AN IMPLICIT SIMULATION ............................................................................. P.1
LINEAR EQUATION SOLVER .................................................................................................. P.2
NONLINEAR EQUATION SOLVER.......................................................................................... P.3
ELEMENT FORMULATIONS FOR IMPLICIT ANALYSIS..................................................... P.4
APPLYING LOADS DURING IMPLICIT ANALYSIS.............................................................. P.5
AUTOMATIC TIME STEP SIZE CONTROL............................................................................. P.5
IMPLICIT STRESS INITIALIZATION....................................................................................... P.6
TROUBLESHOOTING CONVERGENCE PROBLEMS............................................................ P.6
APPENDIX Q
USER DEFINED WELD FAILURE ............................................................................................Q.1
APPENDIX R
USER DEFINED COHESIVE MODEL.......................................................................................R.1
APPENDIX S
USER DEFINED BOUNDARY FLUX........................................................................................ S.1
INTRODUCTION
LS-DYNA Version 971 I.1 (INTRODUCTION)
LS-DYNA USER’S MANUAL
INTRODUCTION
CHRONOLOGICAL HISTORY
DYNA3D originated at the Lawrence Livermore National Laboratory [Hallquist 1976].
The early applications were primarily for the stress analysis of structures subjected to a variety of
impact loading. These applications required what was then significant computer resources, and
the need for a much faster version was immediately obvious. Part of the speed problem was
related to the inefficient implementation of the element technology which was further aggravated
by the fact that supercomputers in 1976 were much slower than today’s PC. Furthermore, the
primitive sliding interface treatment could only treat logically regular interfaces that are
uncommon in most finite element discretizations of complicated three-dimensional geometries;
consequently, defining a suitable mesh for handling contact was often very difficult. The first
version contained trusses, membranes, and a choice of solid elements. The solid elements
ranged from a one-point quadrature eight-noded element with hourglass control to a twenty-
noded element with eight integration points. Due to the high cost of the twenty node solid, the
zero energy modes related to the reduced 8-point integration, and the high frequency content
which drove the time step size down, higher order elements were all but abandoned in later
versions of DYNA3D. A two-dimensional version, DYNA2D, was developed concurrently.
A new version of DYNA3D was released in 1979 that was programmed to provide near
optimal speed on the CRAY-1 supercomputers, contained an improved sliding interface
treatment that permitted triangular segments and was an order of magnitude faster than the
previous contact treatment. The 1979 version eliminated structural and higher order solid
elements and some of the material models of the first version. This version also included an
optional element-wise implementation of the integral difference method developed by Wilkins
et al. [1974].
The 1981 version [Hallquist 1981a] evolved from the 1979 version. Nine additional
material models were added to allow a much broader range of problems to be modeled including
explosive-structure and soil-structure interactions. Body force loads were implemented for
angular velocities and base accelerations. A link was also established from the 3D Eulerian code,
JOY [Couch, et. al., 1983] for studying the structural response to impacts by penetrating
projectiles. An option was provided for storing element data on disk thereby doubling the
capacity of DYNA3D.
The 1982 version of DYNA3D [Hallquist 1982] accepted DYNA2D [Hallquist 1980]
material input directly. The new organization was such that equations of state and constitutive
models of any complexity could be easily added. Complete vectorization of the material models
had been nearly achieved with about a 10 percent increase in execution speed over the 1981
version.
In the 1986 version of DYNA3D [Hallquist and Benson 1986], many new features were
added, including beams, shells, rigid bodies, single surface contact, interface friction, discrete
springs and dampers, optional hourglass treatments, optional exact volume integration, and
VAX/ VMS, IBM, UNIX, COS operating systems compatibility, that greatly expanded its range
of applications. DYNA3D thus became the first code to have a general single surface contact
algorithm.
In the 1987 version of DYNA3D [Hallquist and Benson 1987] metal forming simulations
and composite analysis became a reality. This version included shell thickness changes, the
Belytschko-Tsay shell element [Belytschko and Tsay, 1981], and dynamic relaxation. Also
INTRODUCTION
I.2 (INTRODUCTION) LS-DYNA Version 971
included were non-reflecting boundaries, user specified integration rules for shell and beam
elements, a layered composite damage model, and single point constraints.
New capabilities added in the 1988 DYNA3D [Hallquist 1988] version included a cost
effective resultant beam element, a truss element, a C
0
triangular shell, the BCIZ triangular shell
[Bazeley et al. 1965], mixing of element formulations in calculations, composite failure
modeling for solids, noniterative plane stress plasticity, contact surfaces with spot welds, tie
break sliding surfaces, beam surface contact, finite stonewalls, stonewall reaction forces, energy
calculations for all elements, a crushable foam constitutive model, comment cards in the input,
and one-dimensional slidelines.
By the end of 1988 it was obvious that a much more concentrated effort would be
required in the development of this software if problems in crashworthiness were to be properly
solved; therefore, Livermore Software Technology Corporation was founded to continue the
development of DYNA3D as a commercial version called LS-DYNA3D which was later
shortened to LS-DYNA. The 1989 release introduced many enhanced capabilities including a
one-way treatment of slide surfaces with voids and friction; cross-sectional forces for structural
elements; an optional user specified minimum time step size for shell elements using elastic and
elastoplastic material models; nodal accelerations in the time history database; a compressible
Mooney-Rivlin material model; a closed-form update shell plasticity model; a general rubber
material model; unique penalty specifications for each slide surface; external work tracking;
optional time step criterion for 4-node shell elements; and internal element sorting to allow full
vectorization of right-hand-side force assembly.
During the last ten years, considerable progress has been made as may be seen in the
chronology of the developments which follows.
Capabilities added in 1989-1990:
• arbitrary node and element numbers,
• fabric model for seat belts and airbags,
• composite glass model,
• vectorized type 3 contact and single surface contact,
• many more I/O options,
• all shell materials available for 8 node thick shell,
• strain rate dependent plasticity for beams,
• fully vectorized iterative plasticity,
• interactive graphics on some computers,
• nodal damping,
• shell thickness taken into account in shell type 3 contact,
• shell thinning accounted for in type 3 and type 4 contact,
• soft stonewalls,
• print suppression option for node and element data,
• massless truss elements, rivets – based on equations of rigid body dynamics,
• massless beam elements, spot welds – based on equations of rigid body dynamics,
• expanded databases with more history variables and integration points,
• force limited resultant beam,
• rotational spring and dampers, local coordinate systems for discrete elements,
• resultant plasticity for C
0
triangular element,
• energy dissipation calculations for stonewalls,
• hourglass energy calculations for solid and shell elements,
• viscous and Coulomb friction with arbitrary variation over surface,
• distributed loads on beam elements,
• Cowper and Symonds strain rate model,
• segmented stonewalls,
• stonewall Coulomb friction,
• stonewall energy dissipation,
• airbags (1990),
INTRODUCTION
LS-DYNA Version 971 I.3 (INTRODUCTION)
• nodal rigid bodies,
• automatic sorting of triangular shells into C
0
groups,
• mass scaling for quasi static analyses,
• user defined subroutines,
• warpage checks on shell elements,
• thickness consideration in all contact types,
• automatic orientation of contact segments,
• sliding interface energy dissipation calculations,
• nodal force and energy database for applied boundary conditions,
• defined stonewall velocity with input energy calculations,
Capabilities added in 1991-1992:
• rigid/deformable material switching,
• rigid bodies impacting rigid walls,
• strain-rate effects in metallic honeycomb model 26,
• shells and beams interfaces included for subsequent component analyses,
• external work computed for prescribed displacement/velocity/accelerations,
• linear constraint equations,
• MPGS database,
• MOVIE database,
• Slideline interface file,
• automated contact input for all input types,
• automatic single surface contact without element orientation,
• constraint technique for contact,
• cut planes for resultant forces,
• crushable cellular foams,
• urethane foam model with hysteresis,
• subcycling,
• friction in the contact entities,
• strains computed and written for the 8 node thick shells,
• “good” 4 node tetrahedron solid element with nodal rotations,
• 8 node solid element with nodal rotations,
• 2x2 integration for the membrane element,
• Belytschko-Schwer integrated beam,
• thin-walled Belytschko-Schwer integrated beam,
• improved TAURUS database control,
• null material for beams to display springs and seatbelts in TAURUS,
• parallel implementation on Crays and SGI computers,
• coupling to rigid body codes,
• seat belt capability.
Capabilities added in 1993-1994:
• Arbitrary Lagrangian Eulerian brick elements,
• Belytschko-Wong-Chiang quadrilateral shell element,
• Warping stiffness in the Belytschko-Tsay shell element,
• Fast Hughes-Liu shell element,
• Fully integrated thick shell element,
• Discrete 3D beam element,
• Generalized dampers,
• Cable modeling,
• Airbag reference geometry,
• Multiple jet model,
• Generalized joint stiffnesses,
• Enhanced rigid body to rigid body contact,
• Orthotropic rigid walls,
INTRODUCTION
I.4 (INTRODUCTION) LS-DYNA Version 971
• Time zero mass scaling,
• Coupling with USA (Underwater Shock Analysis),
• Layered spot welds with failure based on resultants or plastic strain,
• Fillet welds with failure,
• Butt welds with failure,
• Automatic eroding contact,
• Edge-to-edge contact,
• Automatic mesh generation with contact entities,
• Drawbead modeling,
• Shells constrained inside brick elements,
• NIKE3D coupling for springback,
• Barlat’s anisotropic plasticity,
• Superplastic forming option,
• Rigid body stoppers,
• Keyword input,
• Adaptivity,
• First MPP (Massively Parallel) version with limited capabilities.
• Built in least squares fit for rubber model constitutive constants,
• Large hysteresis in hyperelastic foam,
• Bilhku/Dubois foam model,
• Generalized rubber model,
Capabilities added in 1995:
• Belytschko - Leviathan Shell
• Automatic switching between rigid and deformable bodies.
• Accuracy on SMP machines to give identical answers on one, two or more processors.
• Local coordinate systems for cross-section output can be specified.
• Null material for shell elements.
• Global body force loads now may be applied to a subset of materials.
• User defined loading subroutine.
• Improved interactive graphics.
• New initial velocity options for specifying rotational velocities.
• Geometry changes after dynamic relaxation can be considered for initial velocities..
• Velocities may also be specified by using material or part ID’s.
• Improved speed of brick element hourglass force and energy calculations.
• Pressure outflow boundary conditions have been added for the ALE options.
• More user control for hourglass control constants for shell elements.
• Full vectorization in constitutive models for foam, models 57 and 63.
• Damage mechanics plasticity model, material 81,
• General linear viscoelasticity with 6 term prony series.
• Least squares fit for viscoelastic material constants.
• Table definitions for strain rate effects in material type 24.
• Improved treatment of free flying nodes after element failure.
• Automatic projection of nodes in CONTACT_TIED to eliminate gaps in the surface.
• More user control over contact defaults.
• Improved interpenetration warnings printed in automatic contact.
• Flag for using actual shell thickness in single surface contact logic rather than the
default.
• Definition by exempted part ID’s.
• Airbag to Airbag venting/segmented airbags are now supported.
• Airbag reference geometry speed improvements by using the reference geometry for
the time step size calculation.
• Isotropic airbag material may now be directly for cost efficiency.
• Airbag fabric material damping is specified as the ratio of critical damping.
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