在LS-Prepost建立sph模型地详细过程

LS_Prepost关键操作

1.模型建立

立方体模型

起始坐标

立方体

Part编号

沿三个坐标轴方向的节点数

起始节点号：该Part第一个节点号码

粒子密度

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球体模型

球心坐标

球体

沿三个坐标轴方向的节点数

球体半径

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圆柱体模型

圆柱 方向坐标

底部中心坐标

圆柱高

圆柱半径

径向节点数，一般设置相同

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轴向节点数

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圆台/锥模型

圆台/锥

方向坐标

底部中心坐标

圆台高

圆台底部半径

径向节点数，一般设置相同

圆台顶部半径

轴向节点数

2.参数定义

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*DATABASE_FORMAT计算结果输出格式

数据库

输出结 果格式

IFORM Output format for D3PLOT and D3THDT files

EQ.0: LS-DYNA database format (default), EQ.1: ANSYS database format,

EQ.2: Both LS-DYNA and ANSYS database formats.

IBINARY Word size of the binary output files (D3PLOT, D3THDT, D3DRLF and interface files for bit computer such as CRAY and NEC.

EQ.0: default bit format, EQ.1: 32 bit IEEE format Remarks:

1. This option is not available for every platform. Check LS-DYNA Banner upon

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executionof the program

2. By using this option one can reduce the size of the binary output files which are created by bits computer such as CRAY and NEC.二进制

*DATABASE_EXTENT_BINARY结果输出控制

数据库

输出二进制结果

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NEIPH Number of additional integration point history variables written to the binary data- base for solid elements. The integration point data is written in the same order that it is stored in memory-each material model has its own history variables that are stored. For user defined materials it is important to store the history data that is needed for plotting before the data which is not of interest.

给实体单元增加附加综合的点历史变量二进制数据库，综合点数据目的是储存记忆每个材料模型使它拥有自己的历史变量。对于使用者而言，定义材料对于储存历史数据是很重要的，在数据储存前需要对其进行描绘。

NEIPS Number of additional integration point history variables written to the binary data- base for both shell and thick shell elements for each integration point, see NEIPH above.

给薄壳和厚壳单元增加附加综合的点历史变量二进制数据库，看下面的NEIPH。

MAXINT Number of shell integration points written to the binary database, see also *INTE GRATION_SHELL. If the default value of 3 is used then results are output for the outermost (top) and innermost (bottom) integration points together with results for the neutral axis. If MAXINT is set to 3 and the element has 1 integration point then all three results will be the same. If a value other than 3 is used then results for the first MAXINT integration points in the element will be output. Note: If the element has an even number of integration points and MAXINT is not set to 3 then you will not get mid-surface results. See Remarks below.

壳单元附加综合的点历史变量二进制数据库，可以参看*INTE GRATION_SHELL.

如果采用默认值3，则结果输出的是最远（高）和最近（下）的综合点，结果包含中间轴坐标。如果设置为3，单元有一个综合点，则三个结果将相同。如果值超过3，则在单元中的第一个MAXINT综合点将会被输出。注意：如果单元拥有一系列综合点，而MAXINT没有被设置成3，则你将无法获得中间表面结果值，详见下面的附注。

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STRFLG Set to 1 to dump strain tensors for solid, shell and thick shell elements for plotting by LS-PREPOST and ASCII file ELOUT. For shell and thick shell elements two tensors are written, one at the innermost and one at the outermost integration point. For solid elements a single strain tensor is written.

SIGFLG Flag for including stress tensor in the shell LS-DYNA database:

EQ.1: include (default), EQ.2: exclude.

EPSFLG Flag for including the effective plastic strains in the shell LS-DYNA database:

EQ.1: include (default), EQ.2: exclude.

RLTFLG Flag for including stress resultants in the shell LS-DYNA database: EQ.1: include (default), EQ.2: exclude.

ENGFLG Flag for including shell internal energy density and thickness in the

LSDYNA database:

EQ.1: include (default), EQ.2: exclude.

CMPFLG Orthotropic and anisotropic material stress and strain output in local material coordinate system for solids, shells and thick shells. EQ.0: global, EQ.1: local.

IEVERP Every plot state for “d3plot” database is written to a separate file. This option will limit the database to 1000 states: EQ.0: more than one state can be on each plotfile, EQ.1: one state only on each plotfile.

BEAMIP Number of beam integration points for output. This option does not apply to beams that use a resultant formulation.

DCOMP Data compression to eliminate rigid body data: EQ.1: off (default), no rigid body data compression, EQ.2: on, rigid body data compression active,

EQ.3: off, no rigid body data compression, but nodal velocities and accelerations are eliminated from the database.

EQ.4: on, rigid body data compression active and nodal velocities and accelerations are eliminated from the database. SHGE Output shell hourglass energy density:

EQ.1: off (default), no hourglass energy written, EQ.2: on.

STSSZ Output shell element time step, mass, or added mass: EQ.1: off (default),

EQ.2: output time step size,

EQ.3: output mass, added mass, or time step size. See remark 3 below. N3THDT Material energy write option for D3THDT database

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EQ.1: off, energy is NOT written to D3THDT database,

EQ.2: on (default), energy is written to D3THDT database. IALEMAT Output solid part ID list containing ale materials. EQ.1: on (default)

NINTSLD Number of solid element integration points written to the LS-DYNA database. The default value is 1. For solids with multiple integration points NINTSLD may be set to 8. Currently, no other values for NINTSLD are allowed. For solids with multiple integration points, an average value is output if NINTSLD is set to 1.

PKP_SEN Flag to output the peak pressure and surface energy computed by each contact interface into the interface force database. To obtain the surface energy, FRCENG, must be sent to 1 on the control contact card. When PKP_SEN=1, it is possible to identify the energies generated on the upper and lower shell surfaces, which is important in metal forming appli- cations. This data is mapped after each H-adaptive remeshing. EQ.0: No data is written

EQ.1: Output the peak pressures and surface energy by contact interface SCLP A scaling parameter used in the computation of the peak pressure. This parameter is generally set to unity (the default), but it must be greater than 0.

MSSCL Output nodal information related to mass scaling into the D3PLOT database. This option can be activated if and only if DT2MS < 0.0, see control card *CONTROL_TIMESTEP. This option is available starting with the second release of Version 971.

EQ.0: No data is written

EQ.1: Output incremental nodal mass

EQ.2: Output percentage increase in nodal mass

THERM Output of thermal data to d3plot. The use of this option (THERM>0) may make the database incompatible with other 3rd party software.

EQ.0: (default) output temperature EQ.1: output temperature

EQ.2: output temperature and flux

EQ.3: output temperature, flux, and shell bottom and top surface temperature Remarks:

1. If MAXINT is set to 3 then mid-surface, inner-surface and outer-surface stresses are output at the center of the element to the LS-DYNA database. For an even number of integration points, the points closest to the center are averaged to obtain the midsurface values. If multiple integration points are used in the shell plane, the stresses at the center of the element are found by computing the average of these points. For MAXINT equal to 3 LS-DYNA assumes that the data for the user defined integration rules are ordered from bottom to top even if this is not the case. If MAXINT is not equal to 3, then the stresses at the center of the element are output in the order that they are stored for the selected integration rule. If multiple points are used in plane the stresses are first

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averaged. 2. Beam stresses are output to the LS-DYNA database if and only if BEAMIP is greater than

zero. In this latter case the data that is output is written in the same order that the integration points are defined. The data at each integration point consists of the followingfive values for elastic-plastic Hughes-Liu beams: the normal stress, rr; the transverse shear stresses, rs and tr; the effective plastic strain, and the axial strain which is logarithmic. For beams that are not elastic-plastic, the first history variable, if any, is output instead of the plastic strain. For the beam elements of Belytschko and his coworkers, the transverse shear stress components are not used in the formulation. No data is output for the Belytschko-Schwer resultant beam.

3. If mass scaling is active, the output of the time step size reveals little information about the calculation. If global mass scaling is used for a constant time step, the total element mass is output; however, if the mass is increased so that a minimum time step size is maintained (DT2MS is negative), the added mass is output. Also, see the control card *CONTROL _TIMESTEP.

*DATABASE_BINARY_D3PLOT结果输出时间步长

数据库

输出时间步长

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DT Time interval between outputs.

CYCL Output interval in time steps (a time step is a cycle). For the D3DRFL file a positive number 'n' will cause plot dumps to be written at every n'th convergence check interval speci- fied on the *CONTROL_DYNAMIC_RELAXATION card.

NR Number of Running Restart Files, RUNRSF, written in a cyclical fashion. The default number is one, i.e. the same file is overwritten each time.

LCDT Optional load curve ID specifying time interval between dumps. This option is only available for the D3PLOT, D3PART, D3THDT and INTFOR files. BEAM Option flag for *DATABASE_BINARY_D3PLOT or D3PART.

EQ.0: Discrete spring and damper elements are added to the D3PLOT or D3PART database where they are display as beam elements. The element global X, global Y, global Z and resultant forces are written to the database,

EQ.1: No discrete spring and damper elements are added to the D3PLOT or D3PART database. This option is useful when translating old LS-DYNA input decks to KEYWORD input. In older input decks there is no requirement that beam and spring elements have unique ID's, and beam elements may be created for the spring and dampers with identical ID's to exist- ing beam elements causing a fatal error. Contact interfaces which are based on part IDs of seat- belt elements will not be properly generated if this option is used. EQ.2: Discrete spring and damper elements are added to the D3PLOT or D3PART database where they are displayed as beam elements (similar to option 0). In this option the element resultant force is written to its first database position allowing beam axial forces and spring resultant forces to be plotted at the same time. This can be useful during some post-processing applications.

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NPLTC DT=ENDTIME/NPLTC applies to D3PLOT and D3PART only. This overrides the DT specified in the first field.

PSETID SET_PART ID for D3PART only.

IOOPT This option applies to the D3PLOT file only. Flag to govern behavior of the plot fre- quency load curve defined by LCDT:

EQ.1: At the time each plot is generated, the load curve value is added to the current time to determine the next plot time (this is the default behavior).

EQ.2: At the time each plot is generated, the next plot time T is computed so that T = the current time plus the load curve value at time T.

EQ.3: A plot is generated for each abscissa point in the load curve definition. The actual value of the load curve is ignored

*CONTROL_SPH

SPH

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NCBS Number of cycles between particle sorting 粒子分类搜索循环次数

BOXID SPH approximations are computed inside a specified BOX. When a particle has gone outside the BOX, it is deactivated. This will save computational time by eliminating particles that no longer interact with the structure.

指定BOX内的SPH粒子参与计算。当某个SPH粒子位于BOX之外时，该粒子失效，通过消除某些不再与结构发生作用的粒子，可以节省计算时间。

DT Death time. Determines when the SPH calculations are stopped. 粒子失效时间 IDIM Space dimension for SPH particles: SPH粒子的空间维数

3 for 3D problems 参数为3时，表示3维问题。

2 for 2D plane strain problems 参数为2时，表示2维问题。 -2 for 2D axisymmetric problems参数为-2时，表示轴对称问题。

When a value is not specified LS-DYNA determines the space dimension automatically by checking the use of 3D, 2D or 2D asisymmetric elements. 当这个值无法自动指定LS-DYNA的维数，程序通过核对使用3维、2维或轴对称的单元来确定空间维数。

MEMORY Defines the initial number of neighbors per particle. This variable is just for memory allocation of arrays during the initialization phase. During the calculation, some particles can request more neighbors and LS-DYNA will

automatically adapt the size of that variable. Default value should apply for most applications.

定义每个粒子的初始相邻粒子的数量，该变量只是在初始化阶段调整内存分配。在计算中，如果某些粒子需要更多的相邻粒子，LS-DYNA会自动调整该变量设置。默认值适用于大部分问题。

FORM Particle approximation theory: 粒子近似理论

EQ. 0: default formulation, 默认公式

EQ. 1: remormalization approximation 重归-近似化

START Start time for particle approximation. Particle approximations will be

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computed when time of the analysis has reached the value defined in START. 粒子近似开始时间。当分析时间达到所设定的值时，粒子将开始计算。

MAXV Maximum value for velocity for the SPH particles. Particles with a velocity greater than MAXV are deactivated SPH粒子速度最大值，如果速度超过该值，质点将会失效。

CONT Defines the computation of the particle approximation between two different

SPH parts: 两个不同的SPH组之间粒子近似的计算设置。

EQ. 0: Particle approximation is defined (default)参数设为0 计算粒子近似

（默认值）

EQ. 1: Particle approximation is not computed. Two different SPH materials will not interact with each other and penetration is allowed. 参数设为1 不计算粒子近似，两种不同的SPH材料不会发生相互作用，允许相互穿透。

DERIV Time integration type for the smoothing length:光滑长度的时间积分类型。

d1(h(t))=h(t)div(v)(default)dtd

d1EQ.1:(h(t))=h(t)(div(v))1/3dtdEQ.0:

*CONTROL_CONTACT

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Card 3 is optional. The following parameters are the default values used by parts in

automatic contacts. These frictional coefficients apply only to contact types: SINGLE_SURFACE, AUTOMATIC_GENERAL, AUTOMATIC_SINGLE_ SURFACE, AUTOMATIC_NODES_TO_..., AUTOMATIC_SURFACE_..., and AUTOMATIC_

ONE_WAY_...., and ERODING_SINGLE_SURFACE. Also see *CONTACT and *PART.Note that these default values will override the values specified for these contact types in the*CONTACT section. 文案大全

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SLSFAC Scale factor for sliding interface penalties, SLSFAC:

EQ.0: default = .1. RWPNAL Scale factor for rigid wall penalties, which treat nodal points interacting with rigid walls, RWPNAL. The penalties are set so that an absolute value of unity should be optimal; however, this penalty value may be very problem dependent. If rigid/deformable materials switching is used, this option should be used if the switched materials are interacting with rigid walls. LT.0.0: all nodes are treated by the penalty method. This is required for implicit calcula- tions. Since seven (7) variables are stored for each slave node, only the nodes that may interact with the wall should be included in the node list.

EQ.0.0: the constraint method is used and nodal points which belong to rigid bodies are not considered. GT.0.0: rigid bodies nodes are treated by the penalty

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method and all other nodes are treated by the constraint method.

ISLCHK Initial penetration check in contact surfaces with indication of initial penetration in output files (see remarks below):

EQ.0: the default is set to 1, EQ.1: no checking,

EQ.2: full check of initial penetration is performed. SHLTHK Shell thickness considered in type surface to surface and node to surface type contact options, where options 1 and 2 below activate the new contact algorithms. The thick- ness offsets are always included in single surface, constraint method, and automatic surface to surface and node to surface contact types (See remarks below.):

EQ.0: thickness is not considered,

EQ.1: thickness is considered but rigid bodies are excluded, EQ.2: thickness is considered including rigid bodies.

PENOPT Penalty stiffness value option. For default calculation of the penalty value please refer to the LS-DYNA Theory Manual.

EQ.0: the default is set to 1,

EQ.1: minimum of master segment and slave node (default for most contact types),

EQ.2: use master segment stiffness (old way), EQ.3: use slave node value,

EQ.4: use slave node value, area or mass weighted,

EQ.5: same as 4 but inversely proportional to the shell thickness.This may require special scaling and is not generally recommended. Options 4 and 5 can be used for metalforming calculations.

THKCHG Shell thickness changes considered in single surface contact:

EQ.0: no consideration (default),

EQ.1: shell thickness changes are included.

ORIEN Optional automatic reorientation of contact interface segments during initialization:

EQ.0: default is set to 1.

EQ.1: active for automated (part) input only. Contact surfaces are given by *PART definitions.

EQ.2: active for manual (segment) and automated (part) input. EQ.3: inactive for non-forming contact. EQ.4: inactive for forming contact.

ENMASS Treatment of the mass of eroded nodes in contact. This option affects all contact types where nodes are removed after surrounding elements fail. Generally, the removal of eroded nodes makes the calculation more stable; however, in problems where erosion is impor- tant the reduction of mass will lead to incorrect results.

EQ.0: eroding nodes are removed from the calculation.

EQ.1: eroding nodes of solid elements are retained and continue to be active in contact.

EQ.2: the eroding nodes of solid and shell elements are retained and continue

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to be active in contact.

USRSTR Storage per contact interface for user supplied interface control subroutine, see Appendix F. If zero, no input data is read and no interface storage is permitted in the user subroutine. This storage should be large enough to accommodate input parameters and any history data.This input data is available in the user supplied subroutine.

USRFRC Storage per contact interface for user supplied interface friction subroutine, see Appendix G. If zero, no input data is read and no interface storage is permitted in the user subroutine. This storage should be large enough to accommodate input parameters and any history data. This input data is available in the user supplied subroutine.

NSBCS Number of cycles between contact searching using three dimensional bucket searches. Defaults recommended.

INTERM Flag for intermittent searching in old surface-to-surface contact using the interval specified as NSBCS above:

EQ.0: off, EQ.1: on.

XPENE Contact surface maximum penetration check multiplier. If the small penetration checking option, PENCHK, on the contact surface control card is active, then nodes whose penetration then exceeds the product of XPENE and the element thickness are set free, see *CONTACT_OPTION_...:

EQ.0: default is set to 4.0. SSTHK Flag for using actual shell thickness in single surface contact logic-types4, 13, 15 and 26. See remarks 1 and 2 below.

EQ.0: Actual shell thickness is not used in the contacts. (default),

EQ.1: Actual shell thickness is used in the contacts. (sometimes recommended for metal forming calculations).

ECDT Time step size override for eroding contact:

EQ.0: contact time size may control Dt.

EQ.1: contact is not considered in Dt determination.

TIEDPRJ Bypass projection of slave nodes to master surface in types: *CONTACT_TIED_NODES_TO_SURFACE,

*CONTACT_TIED_SHELL_EDGE_TO_SURFACE, and

*CONTACT_TIED_SURFACE_TO_SURFACE tied interface

options:

EQ.0: eliminate gaps by projection nodes,

EQ.1: bypass projection. Gaps create rotational constraints which can substantially affect results.

SFRIC Default static coefficient of friction (see *PART_CONTACT) DFRIC Default dynamic coefficient of friction (see *PART_CONTACT) EDC Default exponential decay coefficient (see *PART_CONTACT) VFC Default viscous friction coefficient (see *PART_CONTACT) TH Default contact thickness (see *PART_CONTACT)

TH_SF Default thickness scale factor (see *PART_CONTACT)

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PEN_SF Default local penalty scale factor (see *PART_CONTACT)

IGNORE Ignore initial penetrations in the *CONTACT_AUTOMATIC options. In the SMP contact this flag is not implement for the AUTOMATIC_GENERAL option. “Initial” in this context refers to the first timestep that a penetration is encountered. This option can also be specified for each interface on the third optional card under the keyword, *CONTACT. The value defined here will be the default.

EQ.0: move nodes to eliminate initial penetrations in the model definition. EQ.1: allow initial penetrations to exist by tracking the initial penetrations.

EQ.2: allow initial penetrations to exist by tracking the initial penetrations. However, penetration warning messages are printed with the original coordinates and the recommended coordinates of each slave node given. FRCENG Flag to activate the calculation of frictional sliding energy:

EQ.0: do not calculate,

EQ.1: calculate frictional energy in contact and store as “Surface Energy Density” in the binary INTFOR file. Convert mechanical frictional energy to heat when doing a coupled thermal-mechanical problem. When PKP_SEN=1 on the keyword card *DATABASE_

EXTENT_BINARY, it is possible to identify the energies generated on the upper and lower shell surfaces, which is important in metal forming applications. This data is mapped after each H-adaptive remeshing.

SKIPRWG Flag not to display stationary rigid wall by default.

EQ.0: generate 4 extra nodes and 1 shell element to visualize stationary planar rigid wall.

EQ.1: do not generate stationary rigid wall.

OUTSEG Flag to output each beam spot weld slave node and its master segment for contact type: *CONTACT_SPOTWELD into the D3HSP file.

EQ.0: no, do not write out this information. EQ.1: yes, write out this information.

SPOTSTP If a spot weld node or face, which is related to a *MAT_SPOTWELD beam or solid element, respectively, cannot be found on the master surface, should an error termination occur?

EQ.0: no, continue calculation,

EQ.1: yes, print error message and terminate,

EQ.2: no, delete unconstrained weld and continue calculation.

SPOTDEL If the nodes of a spot weld beam or solid element are attached to a shell element that fails and are deleted, then the attached spot weld element is deleted if this flag is on. There is a small cost penalty related to this option on non-vector processors. On vector processors, however, this option can

significantly slow down the calculation if many weld elements fail since the vector lengths are reduced.

EQ.0: no, do not delete the spot weld beam or solid element,

EQ.1: yes, delete the weld elements when the attached shells on one side of the element fail.

SPOTHIN Optional thickness scale factor. If active, define a factor greater than

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zero, but less than one. Premature failure of spot welds can occur due to contact of the spot welded parts in the vicinity of the spot weld. This contact creates tensile forces in the spot weld. Although this seems physical, the compressive forces generated in the contact are large enough to fail the weld in tension before failure is observed in experimental test. With this option, the thickness of the parts in the vicinity of the weld are automatically scaled, the contact forces do not

develop, and the problem is avoided. We recommend setting the IGNORE option to 1 or 2 if SPOTHIN is active. This option applies only to the AUTOMATIC_SINGLE_SURFACE option.

ISYM Symmetry plane option default for automatic segment generation when contact is defined by part ID’s:

EQ.0: off,

EQ.1: do not include faces with normal boundary constraints (e.g.,segments of brick elements on a symmetry plane).This option is important to retain the correct boundary conditions in themodel with symmetry. NSEROD Flag to use one-way node to surface erosion

EQ.0: use two-way algorithm EQ.1: use one-way algorithm

RWGAPS Flag to add rigid wall gap stiffness, see parameter RWGDTH below.

EQ.1: add gap stiffness

EQ.2: do not add gap stiffness RWGDTH Death time for gap stiffness. After this time the gap stiffness is no longer added.

RWKSF Rigid wall penalty scale factor for contact with deformable parts during implicit calculations. This value is independent of SLSFAC and RWPNAL. If RWKSF is also specified in *RIGIDWALL_PLANAR,the stiffness is scaled by the product of the two values.

ICOV Invokes the covariant formulation of Konyukhov and Schweizerhof in the FORMING contact option. This option is available in the third revision of version 971, but is not recom- mended since it is still being implemented.

EQ.0: standard formulation (default) EQ.1: covariant contact formulation.

SWRADF Spot weld radius scale factor for neighbor segment thinning

EQ.0: neighbor segments not thinned (default)

GT.0: The radius of beam spot welds are scaled by SWRADF when searching for close neighbor segments to thin.

ITHOFF Flag for offsetting thermal contact surfaces for thick thermal shells

EQ.0: No offset, if thickness is not included in the contact the heat will be transferred between the mid-surfaces of the corresponding contact segments (shells).

EQ.1: Offsets are applied so that contact heat transfer is always between the outer surfaces of the contact segments (shells).

SHLEDG Flag for assuming edge shape for shells when measuring penetration. This is available for segment based contact (see SOFT on *CONTACT)

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EQ.0: Shell edges are assumed round (default), EQ.1: Shell edges are assumed square. Remarks:

1. The shell thickness change option must be activated in CONTROL_SHELL control input

(see ISTUPD) and a nonzero flag specified for SHLTHK above before the shell thickness changes can be included in the surface-to-surface contact types. An additional flag must be set, see THKCHG above, if thickness changes are included in the single surface contact algorithms. The contact algorithms that include the shell thickness are relatively recent and are now fully optimized and parallelized. The searching in these algorithms is considerably more extensive and therefore slightly more expensive.

2. In the single surface contacts types SINGLE_SURFACE, AUTOMATIC_SINGLE_ SURFACE, AUTOMATIC_GENERAL, AUTOMATIC_GENERAL_INTERIOR and

ERODING_SINGLE_SURFACE, the default contact thickness is taken as the smaller of two values -- the shell thickness or 40% of the minimum edge length. This may create unexpected difficulties if it is the intent to include thickness effects when the in-plane shell element dimen- sions are less than the thickness. The default is based on years of experience where it has been observed that sometimes rather large nonphysical thicknesses are specified to achieve high stiffness values. Since the global searching algorithm includes the effects of shell thicknesses, it is possible to slow the searches down considerably by using such nonphysical thickness dimensions. 3. The initial penetration check option is always performed in v. 950 irregardless of the value of ISLCHK. If you do not want to remove initial penetrations then set the contact birth time (see *CONTACT_...) so that the contact is not active at time 0.

4. Automatic reorientation requires offsets between the master and slave surface segments.The reorientation is based on segment connectivity and, once all segments are oriented consistently based on connectivity, a check is made to see if the master and slave surfaces face each other based on the right hand rule. If not, all segments in a given surface are reoriented. This proce- dure works well for non-disjoint surfaces. If the surfaces are disjoint, the AUTOMATIC contact options, which do not require orientation, are recommended. In the FORMING contact options automatic reorientation works for disjoint surfaces.

5. If SPOTHIN is greater than zero and SWRADF is greater than zero, a neighbor segment thinning option is active. The radius of a beam spot weld is scaled by SWRADF, and then a search is made for shell segments that are neighbors of the tied shell segments that are touched by the weld but not tied by it.

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*CONTROL_TERMINATION

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ENDTIM Termination time. Mandatory.

ENDCYC Termination cycle. The termination cycle is optional and will be used if the specified cycle is reached before the termination time. Cycle number is identical with the time step number.

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DTMIN Reduction (or scale) factor for initial time step size to determine minimum time step, TSMIN. TSMIN=DTSTART*DTMIN where DTSTART is the initial step size determined by LS-DYNA. When TSMIN is reached, LS-DYNA terminates with a restart dump.

ENDENG Percent change in energy ratio for termination of calculation. If undefined, this option is inactive.

ENDMAS Percent change in the total mass for termination of calculation. This option is relevant if and only if mass scaling is used to limit the minimum time step size, see *CONTROL_TIMESTEP variable name “DT2MS”. Remarks:

1. Termination by displacement may be defined in the *TERMINATION section. 2. If the erosion flag on *CONTROL_TIMESTEP is set (ERODE=1), then the shell elements and solid elements with time steps falling below TSMIN will be eroded.

*BOUNDARY_SPH_SYMMETRY_PLANE

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VTX x-coordinate of tail of a normal vector originating on the wall (tail) and

terminating in the body (head) (i.e., vector points from the symmetry plane into the body).对称边界面的法向向量尾的X坐标，向量尾起始于对称平面，向量头指向SPH粒子内部

VTY y-coordinate of tail 法向向量尾Y坐标 VTZ z-coordinate of tail 法向向量尾Z坐标 VHX x-coordinate of head 法向向量头X坐标 VHY y-coordinate of head 法向向量头Y坐标 VHZ z-coordinate of head 法向向量头Z坐标 Remarks:

1. A plane of symmetry is assumed for all SPH elements defined in the model. 一个对称平面假设用来定义模型所有的SPH单元

2. The plane of symmetry has to be normal to either the x,y or z direction 对称平面必须得有正常的X,Y或Z指向

*CONTACT_ERODING_NODES_TO_SURFACE

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