Ls_dyna 沙漏控制考试试题

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LS-DYNA常见问题及解决策略 (2012年11月7日)

LS‐DYNA求解器
支持单机和并行计算支持Windows、Unix、Linux等系统有32位、64位版本有单精度、双精度版本
LS‐DYNA求解器
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湖南大学汽车车身先进设计制造国家重点实验室
LS‐DYNA基础
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汽车工业：碰撞分析、气囊设计、约束系统匹配、部件加工航空航天：鸟撞、飞机结构冲击动力分析、碰撞，坠毁、冲击爆炸及动态载荷、火箭级间分离模拟分析、宇宙垃圾碰撞、特种复合材料设计制造业：冲压、锻造、铸造、切割建筑业：地震安全、混凝土结构、爆破拆除、公路桥梁设计国防工业：内弹道和终点弹道、装甲和反装甲系统、穿甲弹与破甲弹设计、战斗部结构设计、空气，水与土壤中爆炸电子领域：跌落分析、包装设计、热分析、电子封装生物医学
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湖南大学汽车车身先进设计制造国家重点实验室
LS‐DYNA基础 LS‐DYNA基本分析流程
几何模型修正几何模型读取
湖南大学汽车车身先进设计制造国家重点实验室
LS‐DYNA基础
前处理软件
FEMB LS‐PREPOST HYPERMESH ANSYS PATRAN FEMAP
沙漏的产生
有限元计算的数值积分采用高斯积分方法
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湖南大学汽车车身先进设计制造国家重点实验室
Hourglass
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LSS-BB模拟试题

編號題目連結2确定项目选择及项目优先级是下列哪个角色的责任：黑带大师3在分析 X - R控制图时应：先分析R 图然后再分析X图5质量管理大师戴明先生在其著名的质量管理十四条中指出“停止依靠检验达成质量的做法”，这句话的含义是：决定客户需求10在质量功能展开(QFD, Quality Function Deployment) 中，首要的工作是：决定客户需求11在某检验点，对1000 个某零件进行检验，每个零件上有10 个缺陷机会，结果共发现16个零件不合格，合计32 个缺陷，则DPMO：14哪种工具可以用于解决下述问题：一项任务可以分解为许多作业，这些作业相互依赖和相互制约，团队希望把各项作业之间的这种依赖和制约关系清晰地表示出来，并通过适当的分析找出影响进度的关键路径，从而能进行统筹协调。

：箭条图(网络图)15下述团队行为标示着团队进入了哪个发展阶段？团队的任务已为其成员所了解，但他们对实现目标的最佳方法存在着分歧，团队成员仍首先作为个体来思考，并往往根据自己的经历做出决定。

这些分歧可能引起团队内的争论甚至矛盾。

16在界定阶段结束时，下述哪些内容应当得以确定？1、项目目标2、项目预期的财务收益3、项目所涉及的主要过程4、项目团队成员17在项目特许任务书(Team Charter)中，需要陈述“经营情况”（Business Case,也被称为项目背景）。

该项内容是为了说明：20劣质成本的构成是：28下表是一个分组样本, 则其样本均值X 近似为連結29在某快餐店中午营业期间内，每分钟顾客到来人数为平均值是8 的泊松（Poisson）分布。

若考虑每半分钟到来的顾客分布，则此分布近似为：平均值是4 的泊松（Poisson）分布30 一批产品分一、二、三级，其中一级品是二级品的二倍，三级品是二级品的一半，若从该批产品中随机抽取一个，此产品为二级品的概率是39在钳工车间自动钻空的过程中，取30 个钻空结果分析，其中心位置与规定中心点在水平方向的偏差值的平均值为1 微米，标准差为8 微米。

车工理论考试试题(含答案)ls

车工考试试题（含答案）一、单项选择题1．坐标系内某一位置的坐标尺寸上以相对于( C)一位置坐标尺寸的增量进行标注或计量的，这种坐标值称为增量坐标。

A、第B、后C、前D、左2．硬质合金是由( A )、碳化钛粉末，用钴作黏结剂，经高压成型、高温煅烧而成。

A、碳化钨B、碳化物C、氮化钨D、碳化铌3．工件原点设定的依据是：既要符合图样尺寸的标注( B )，又要便于编程。

A、规则B、习惯C、特点D、清晰4．几个定位点同时限制( C )自由度的，称为重复定位。

A、三个B、几个C、同一个D、全部5．若齿面锥角为26°33′54″，背锥角为66°29′23″，此时背锥面与齿面之间的夹角是( B )。

A、80°25′26″B、86°56′23″C、79°36′45″D、90°6．圆锥体( A )直径 D 可用公式: D = M— 2R（1+1/Cosα/2+tAnα/2）求出。

A、小端B、大端C、内孔D、中端7．正弦规是利用( A )函数关系，与量块配合测量工件角度和锥度的精密量具。

A、三角B、正弦C、余弦D、几何8．已知直角三角形一直角边为17.32mm，它与斜边的夹角为30°，另一直角边的长度是( B )mm 。

A、15B、10C、20D、309．用正弦规检验锥度的量具有检验平板、( A )规、量块、百分表、活动表架等。

A、正弦B、塞C、环D、圆10．车削非整圆孔工件的第二孔过程中，要检验( A )，若发现有误差，应及时调整。

A、中心距 B、外径 C、内径 D、平行度11．常用的夹紧装置有螺旋夹紧装置、( B )夹紧装置和偏心夹紧装置等。

A、螺钉B、楔块C、螺母D、压板12．曲轴:装夹方法主要采用一夹一顶和( D )装夹。

A、鸡心夹B、虎钳C、分度头D、两顶尖13．成型车刀的种类成型刀有普通成型刀、( B )成型刀和圆形成型刀。

A、矩形B、棱形C、六棱形D、三角形14．测量两平行非完整孔的中心距时，用内径百分表或杆式内径千分尺( D )测出两孔间的最大距离，然后减去两孔实际半径之和，所得的差即为两孔的中心距。

2023年版(北京)化工自动化控制仪表考试内部培训题库含答案

2023年版(北京)化工自动化控制仪表考试内部培训题库含答案1、【单选题】()适用于大口径、大流量、低压力、不干净三介质。

（C ）A、套筒阀B、单座阀C、蝶阀2、【单选题】CENTUMCS3000系统中,()是实时控制总线,用于连接系统中各站。

（B ）A、FCSB、V netC、HIS3、【单选题】CENTUMCS3000系统中,实时控制总线V net的传输速度是()。

（C ）A、100MbpsB、128MbpsC、10Mbps4、【单选题】CENTUMCS3000系统中,某回路的报警状态显示为LL,可知该回路发生了()报警。

（C ）A、MV值低低B、SV值低低C、PV值低低5、【单选题】CENTUMCS3000系统中的回路调整画面中,HH是()。

（B ）A、给定值B、高高报警设定值C、输出值6、【单选题】DCS系统本身只是一个软件、硬件的组合体,只有经过()以后才能成为真正适用于生产过程的应用控制系统。

（C ）A、程序编译B、程序下装C、软、硬件组态7、【单选题】D DZ-Ⅲ型仪表采用了集成电路和()型防爆结构,提高了防爆等级、稳定性和可靠性。

（B ）A、隔爆B、安全火花C、增安D、无火花8、【单选题】MY2型手提式1211灭火器的灭火射程是()m。

（A ）A、3B、2C、19、【单选题】一次仪表、电缆护套管、电缆的安装尽可能地远离高温工艺设备和工艺管道、对它们的影响较大的为()。

（B ）A、温差B、温度C、热量10、【单选题】一般情况下,控制器参数整定不合理会产生周期性的激烈振荡。

其中()引起振荡周期最短。

（A ）A、积分时间过小B、比例度过小C、微分时间过大11、【单选题】下面关于串级控制回路的描述中正确的是()。

（B ）A、主、副控制器串接工作,主控制器的输出直接操纵控制阀B、主、副控制器串接工作的双闭环负反馈控制系统C、主、副控制器串接工作,实现对副变量的定值控制12、【单选题】世界上第一台可编程序控制器是由()公司最先研制出来的。

埃斯顿试题——精选推荐

埃斯顿试题⼀．E系列（填空问答）1.E10数码管旁的指⽰LED灯亮时代表轴（未做单向定位）。

2. E10-s ⼯件计数参数的代码为（CNT）, ⽰校参数代码为（PAC）3. E10想要修改参数，需在PN-00处输⼊密码（14789）。

4. E20端⼝定义R代表（退让），x-ip代表（X轴到位），START 代表（换步信号）.5. E20需要修改两个轴的参数，需要输⼊密码进⼊参数界⾯，密码为（14789/36987）,进⼊⽰校参数密码为（1212）。

6. E200系统使⽤伺服驱动⽅式时，系统与伺服之间采取（CAN总线）⽅式传输命令。

7. E200输⼊信号MRDY代表（机床准备好），SRDY代表（系统准备好）。

8.E200系统带EDC,X轴，电机与丝杠之间传动⽐为1:1，丝杠螺距为5mm，X轴显⽰1位⼩数，相乘因⼦和相除因⼦为（2000/1）.9. E200电机驱动⽅式参数设为0，代表使⽤（伺服驱动），设为1，代表使⽤（变频驱动）。

10. 此诊断界⾯，哪个信号有输出，（X--,X+）,如需时Y-输出，该怎么做。

（光标移到Y-，按±键切换输出状态）11.E200带EDC，出现A65，A96报警，代表什么含义。

（通讯故障）12.⽬前市场上两种主流剪板机分别是：(摆式剪板机）和（闸式剪板机)。

13.E200系统和EDC的通讯线上⾯需要加⼀个120欧的电阻，这个电阻应该加在（通讯线的末端或者最远的⼀个EDC伺服上）。

14.恢复EDC系统出⼚值的参数符号是＿FN001＿。

15.E200系统带EDC伺服驱动，报警A.96的意思是＿E200和EDC伺服通讯不良＿。

16.E200系统的参考点输⼊⽅式有＿开机寻找参考点＿和＿⽰教当前位置＿。

17.埃斯顿数控系统编码器的接线在九针插头上Z/C相应焊在___3___ 号脚上。

18.E20+的换步信号应接在输⼊信号点上_____ START _____.。

19.E20+的X轴参数密码是_____ 36987_____。

LS-DYNA Solver Interface 8[1].0 Tutorials

e-mail hwsupport@ support@ francesupport@ hwsupport@altair.de support@
support@altairtorino.it support@altairjp.co.jp
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Geom/Mesh User Disp
QA/Model
Contains a set of macros related to working with model geometry, as well as a set for working with FE mesh.
In this tutorial, you will learn to understand the following components of the LS-Dyna interface:
• LS-DYNA FE input reader • LS-DYNA FE output template • LS-DYNA macro menu • LS-DYNA user profile • On-line help for the HyperMesh DYNA interface HyperMesh’s LS-Dyna FE input translator, FE output template, macro menu, and user profile sets the foundation for using LS -Dyna with HyperMesh.
HyperMesh 8.0 Tutorials – LS-DYNA Solver Interface 1
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LS-DYNA问答总结

1 如何处理LS-DYNA中的退化单元？在网格划分过程中，我们常遇到退化单元，如果不对它进行一定的处理，可能会对求解产生不稳定的影响。

在LS-DYNA中，同一Part ID 下既有四面体，五面体和六面体，则四面体，五面体既为退化单元，节点排列分别为N1，N2，N3，N4，N4，N4，N4，N4和N1，N2，N3，N4，N5，N5，N6，N6。

这样退化四面体单元中节点4有5倍于节点1-3的质量，而引起求解的困难。

其实在LS-DYNA的单元公式中，类型10和15分别为四面体和五面体单元，比退化单元更稳定。

所以为网格划分的方便起见，我们还是在同一Part ID下划分网格，通过*CONTROL_SOLID关键字来自动把退化单元处理成类型10和15的四面体和五面体单元。

2 LS-DYNA中对于单元过度翘曲的情况有何处理方法有两种方法：1. 采用默认B-T算法，同时利用*control_shell控制字设置参数BWC＝1，激活翘曲刚度选项；2. 采用含有翘曲刚度控制的单元算法，第10号算法。

该算法是针对单元翘曲而开发的算法，处理这种情况能够很好的保证求解的精度。

除了上述方法外，在计算时要注意控制沙漏，确保求解稳定。

3 在ANSYS计算过程中结果文件大于8GB时计算自动中断，如何解决这个问题？解决超大结果文件的方案:1. 将不同时间段内的结果分别写入一序列的结果记录文件；2. 使用/assign命令和重启动技术；3. ANSYS采用向指定结果记录文件追加当前计算结果数据方式使用/assign指定的文件，所以要求指定的结果记录文件都是新创建的文件，否则造成结果文件记录内容重复或混乱。

特别是，反复运行相同分析命令流时，在重复运行命令流文件之前一定要删除以前生成的结果文件序列。

具体操作方法和过程参见下列命令流文件的演示。

4关于梁、壳单元应力结果输出的说明问题：怎样显示梁单元径向和轴向的应力分布图（我作的梁单元结果只有变形图DOF SOLUTIN –Translation，但是没有stress等值线图，只有一种颜色）和壳单元厚度方向的应力、变形图（我们只能显示一层应力、变形，不知道是上下表层或中间层的结果）。

ansys上机考试题及参考答案

ansys上机考试题及参考答案一、选择题（每题2分，共20分）1. 在ANSYS中，以下哪个选项不是材料属性的参数？A. 弹性模量B. 泊松比C. 密度D. 摩擦系数答案：D2. ANSYS中，以下哪个命令用于定义几何体？A. /PREP7B. /POST1C. /SOLUD. /FINI答案：A3. 在ANSYS中，以下哪个选项不是施加载荷的方式？A. 压力B. 温度C. 重力D. 惯性答案：D4. ANSYS中，以下哪个选项不是网格划分的控制参数？A. 网格大小B. 网格形状C. 网格密度D. 材料属性答案：D5. 在ANSYS中，以下哪个选项不是边界条件？A. 固定支撑B. 压力载荷C. 位移约束D. 温度变化答案：B6. ANSYS中，以下哪个命令用于求解？A. /SOLUB. /PREP7C. /POST1D. /FINI答案：A7. 在ANSYS中，以下哪个选项不是后处理的功能？A. 查看应力分布B. 查看变形图C. 计算体积D. 定义材料属性答案：D8. ANSYS中，以下哪个命令用于退出求解器？A. /SOLUB. /FINIC. /PREP7D. /POST1答案：B9. 在ANSYS中，以下哪个选项不是网格划分的类型？A. 自由网格B. 映射网格C. 扫掠网格D. 材料属性答案：D10. ANSYS中，以下哪个命令用于退出前处理器？A. /PREP7B. /FINIC. /SOLUD. /POST1答案：B二、填空题（每空1分，共20分）1. 在ANSYS中，定义材料属性的命令是 _ 。

答案：MP2. 施加固定支撑的边界条件的命令是 _ 。

答案：D3. ANSYS中，查看应力分布的后处理命令是 _ 。

答案：PLNSOL, S4. 定义几何体的坐标系的命令是 _ 。

答案：CSYS5. 在ANSYS中，施加重力载荷的命令是 _ 。

答案：CE6. 退出后处理器并返回到前处理器的命令是 _ 。

[LS-DYNA]有限元仿真中的沙漏现象及其控制

总能量=内能+动能+滑移界面能+。

能量之间是可以相互转化的，但是对于动力学问题，总能量一般是不太变的。

也就是能量守恒原理。

沙漏模式也就零能模式，他在理论上是一种存在的一种变形模式，但是在实际模型中是不可能存上的。

零能模式就是指有变形，但是不消耗能量。

显然是一种伪变形模式，若不加以控制，计算模型会变得不稳定，并且计算出来的结果也是没有多大意义的。

要加抵制这种变形模式就得相应的消耗一定的能量，也就是沙漏能，如果这个比值太多，就说明模型和实际的变形有很大的差别，当然是不正确的。

这也是缩减积分所付出的代价。

用全积分单元可以解决这个问题，但是效率不高，有可能导致体积锁死，过刚的一些问题。

1. 沙漏的定义沙漏hourglassing一般出现在采用缩减积分单元的情况下：比如一阶四边形缩减积分单元，该单元有四个节点“o”，但只有一个积分点“*”。

而且该积分点位于单元中心位置，此时如果单元受弯或者受剪，则必然会发生变形，如下图a所示。

但是，现实的情况却是在这三种情况下，单元积分点上的主应力和剪应力状况都没有发生变化，也就是说该单元可以自由地在这三种形态之间转变而无需外力。

很小的扰动理论上可以让单元无限地变形下去，而不会消耗任何能量，这就是所谓的沙漏的零能量模式。

这时就要对沙漏进行控制，比如人为地给单元加上一定的刚度。

沙漏只影响实体和四边形单元，而四面体单元、三角形壳单元、梁单元没有沙漏模式，但四面体单元、三角形壳单元缺点是在许多应用中被认为过于刚硬。

沙漏的影响范围：当显式动态分析使用缩减积分单元时，应判断沙漏是否会显著的影响结果。

一般准则是，沙漏能量不能超过内能的10％。

沙漏影响的查看、判断：沙漏能量和内能的对比可在ASCⅡ文件GLSTAT和MATSDM中看出（这两个需要在前处理时设置，或在K文件中设置：在*control_energy卡片中设置HGEN＝2，而且用*database_glstat和*database_matsum卡分别输出系统和每一个部件的沙漏能），也可在POST20中画出。

2021IBM_L2考试真题模拟汇编

2021IBM_L2考试真题模拟汇编2021IBM_L2考试真题模拟03-181、以下关于TS3310磁带槽位数哪种说法是正确的（）。

（单选题）A. 30至396盒B. 20至256盒C. 24至360盒D. 36至396盒试题答案：A2、最多可由多少个节点组成一个SVC群集？（）（单选题）A. 2个B. 4个C. 8个D. 16个试题答案：C3、以下哪个产品的机械臂上带有冗余的双磁带抓取器，每个抓取器均可以访问到磁带库中的所有槽位？（）（单选题）A. IBM TS3310B. IBM TS3500C. SUN SL8500D. Quantum Scalar 10K试题答案：B4、IBM提供随需应变的IT解决方案是基于三个关键方面考虑，他们是（）。

（单选题）A. 存储整合、虚拟化、自动化B. 应用的可用性、系统优化、个人生产力C. 简化基础架构，信息生命周期，业务连续性D. 总体拥有成本，风险管理，法规遵从试题答案：C5、TSM实现LAN-Free方式需要购买如下哪个TSM组件（）。

（单选题）A. TSM for SANB. TSM for MailC. TSM for Database试题答案：A2021IBM_L2考试真题模拟03-191、IBMTPC（TotalStorage Productivity Center）如何提高个人的生产能力？（）（单选题）A. 防止文件系统和数据库空间使用的不足B. 提高在线备份数据库和应用C. 管理数据库、文件系统、目录和文件级分析D. 自动违规策略报告试题答案：D2、一个使用了EMCDMX-3的用户，现在正在寻找一个替换EMCDMX-3产品，基于性能和功能方面的考虑，哪个产品更适合这样一个机会？（）（单选题）A. DS8000B. DS6800C. DS3400D. DS5020试题答案：A3、XIV相比EMC存储家族，其独一无二的特性是（）。

（单选题）A. 更低的成本B. 海量存储能力C. 使用FATA磁盘D. 快照无损性能试题答案：A4、一个光纤存储区域网环境中一定包括（）。

Ls-dyna_tutorial

A guide forSETTING UPA LS-DYNA MODEL INANSATable of Contents1. Introduction (3)1.1. Prerequisites (3)1.2. Problem description (3)1.3. Data files (4)2. Assembly & Welding management (5)2.1. Input the Ls-Dyna file (5)2.2. Read and Realize Connection Points (6)2.3. Creation of Nodal Rigid Bodies (10)3. Property and Material Validation (12)3.1. Prepare the Properties (12)3.2. Input the Material Database (13)3.3. Update the Materials through the Material Database (13)4. Mass Definition (15)4.1. Additional Mass to the structure (15)5. Adding the Barrier (17)5.1. Input and position the Barrier (17)6. Definition of FE-model Entities (19)6.1. Define the Boundary Conditions (19)6.1.1. Boundary Conditions for the barrier (19)6.1.2. Boundary Conditions for the structure (20)6.2. Define the Initial Velocity (20)6.3. Define the Gravity (21)6.4. Define the Contacts (22)6.5. Define Cross Sections (23)6.6. Add Time History Output Definitions (25)6.6.1. Time History Output Definitions on Nodes (25)6.6.2. Time History Output Definitions on Elements (28)7. Definition of Control Parameters (29)8. Final Steps (30)8.1. Clearing unused entities of the model (30)8.2. Checking the integrity of your model (30)8.3. Organizing your model in Includes (31)8.4. Deck Information report (33)9. Output the file (34)10. View and examine the results in μETA Post Processor (34)1. IntroductionThis tutorial presents all the steps taken, to model a front impact analysis, starting from a FE double box beam structure, to Ls-Dyna FE-model output.The following steps will be described:•Input the Ls-Dyna database containing the FE structure.•Obtain connectivity to the model by using DYNA SPOTWELDs, TIED_NODE_TO_SURFACE CONTACTs, and CONSTRAINED_NODAL_RIGID_BODYs.•Verify Properties and Materials of different parts.•Add to the structure an additional mass.•Input a barrier.•Define the boundary conditions, the initial velocity and the gravity.•Define contacts.•Create Cross Sections.•Add some Database History Output Definitions.•Define all the control parameters.•Delete unused entities.•Perform checks to verify the integrity of the model.•Obtain information for the model.•Create and arrange includes.•Output the .key file ready to be solved in Ls-Dyna.1.1. PrerequisitesReading the 4 pages of section 3. Getting Started of this Tutorial Guide, is recommended in order to obtain a familiarization with the ANSA interface and terminology. Also, reading the Chapters 14, 15, 16, 17, 18 of the ANSA User’s Guide, to obtain a familiarization with the terminology of pre-processing decks in general and the LS-DYNA, in particular. Some basic knowledge of the Ls-Dyna Solver is also suggested.1.2. Problem descriptionThe structure consists of two double metal sheet parts connected along their flanges with mesh-independent connection elements (e.g. DYNA SPOTWELDs). The two box beams are connected with a cylindrical traverse in the middle of their length, while in the front are connected with a double traverse structure. This assembly impacts on a rigid barrier with an initial velocity of 12mm/ms to the +X direction.Structure Properties:E=210.0 kg/mm.ms2ν=0.3v init =12 mm/msBarrier Properties:E=70.0 kg/mm.ms2ν=0.3The Properties with the proper characteristics (e.g. thickness, Material) should be assigned. The model entities have to be created, as well.Note that all the Ls-Dyna entities are displayed with specific symbols and colors so as to help the visual identification and selection.For convention reasons the “Ls-Dyna SECTION__/” entity is referred as “Property”, while the “ANSA Part” as “Part”.1.3. Data filesThe files required for this tutorial are:•One Ls-Dyna [*.key] file containing the double box beam structure.[tutorials/DECKS/lsdyna/tutorial_files/double_rail_initial.key.•One *.xml file containing the connection points [connections.xml].•One Ls-Dyna [*.key] “Material database” file [material_database.key].•One Ls-Dyna [*.key] file containing the barrier [barrier.key].•One Header Ls-Dyna [*.key] file [head er.key].2. Assembly & Welding management2.1. Input the Ls-Dyna fileStart ANSA and activate the FILE>INPUT>LS-DYNA function of the main menu, to read theLs-Dyna file. The File Manager windowappears. Navigate and select the filedouble_rail_initial.key.The ‘Input Parameters’ window appearswhere you can tune all the parametersaccording to your needs. Mind to check theflag button ‘Read Ansa Comments’, in order toretain the information regarding ANSA Parts.2.2. Read and Realize Connection PointsAn already defined file [connections.xml ] will be used for the connections. This file contains the information of the weldingpositions and the ANSA Parts (Module IDs) that will be connected.Read the *.xml file using the FILE>READ SPOTS>XML function in the main menu. The ‘File Manager ’ window appears. Navigate and select the appropriate file. In the READSPOTS Parameters windows press OK.As soon as the *.xml file is read the magenta colored Connection Points and Lines appear in the model. These points and lines already contain the information of the parts to be connected. Therefore it is very important that the Module IDs are correctly assigned to the ANSA parts.The generation of theconnection elements isachieved through the Connection Manager,which is invoked by the functionASSEMBLY>REALIZE in the General Buttons menu.Firstly, the Connection Selection Assistant appears. Here, several filters and selection options can be used to select the desired Connection Points. Press ‘Select ’ button and middle click on the screen to proceed.REALIZESpot Weld PointsAll Spot Weld Points are going to be realized as DYNA SPOTWELDs. The target is to have different Properties for those located at the top and those at the bottom flanges.Deselect the Spot Welds of the bottom flangeswith right click box selection. Now, the weld spots located at the top flanges are only highlighted on the screen and in the list ofConnection Manager.DYNA SPOTWELDIn the field ‘PBEAM ID’ in the connectionmanager type a question mark (?).Notice that only properties compatible with BEAMs (e.g. SECTION_BEAM) can be created in this way. Inside the Property Card set the ELFORM type to 9 S-W.Set the outer and inner diameter for the Beam Property TS1, TS2, TT1, TT2 as shown in image.Inside the MID field type a question mark (?).The 'MATERIAL HELP' window appears. Press NEW>MAT_100 MAT SPOTWELD to create a new Material for the Spotwelds.In the Material Card that appears press OK to create it and then double click on the newly created material inside the Material List in order to assign it to the new Property that you create.Now inside the Property Card the correct Material is assigned with Id 3, that was just created.Press OK in Property Card and then double click on the newly created Property inside the Property List in order to assign it to the Spotwelds that will be realized.In the connection manager, the PBEAM ID field is updated with the ID of the newly created Property. Also, insert 5 for ‘Search Dist’.Spot Weld Points are now ready to be realized. Press the ‘Apply’ button in the Connection Manager.Follow the same procedure to realize the Spot Weld Points located at the bottom flanges. Make sure you will create a different Propertyfor them.Realize all the Seam Lines by selecting for FE Representation ‘CONTACT’. Insert 1.5 for‘Search Dist’.NOTE:- To visualize the generated contact mind to enable the corresponding entity (CONTACT)visibility flag in the Database Browser.2.3. Creation of Nodal Rigid Bodies For the assembly of the two box beams with the Cylindrical Traverse, we aregoing to use elements of type CONSTRAINED_NODAL_RIGID_BODY.Activate the CONSTRAINED>ND_R_BD>2 NODES function in the LS-DYNA deck menu. The ‘ELEMENTS’ DEFINITIONPARAMETERS ’ window appears. Switch the Pick mode to ‘Node Sets’.Select for the first set of nodes,those of the traverse plate that are highlighted with white color, as shown in the image.You can use any feature selection tool to assist you with the node selections. Press middle click to confirm.Proceed with the selection of the second set of nodes. Pick those nodes of the Inner Left Rail that are highlighted with yellow color, as shown in the image.Press middle click to confirm.The Parts Manager appears and the Part where the elements of the Nodal Rigid Body will belongcan be selected.2 NODESND_R_BDAs soon as the Part is selected, the‘CONSTRAINED_NODAL_RIGID_BODY’ entity card appears. Leave the default values, and press the ‘OK’ button.Proceed in the same manner to produce Nodal Rigid Bodies between the hole perimeter of the traverse plate and the Inner Left Rail.When finished dothe same actions,to define NodalRigid Bodiesbetween theTraverse and theInner Right RallOnce the railshave beenassembled withthe cylindricaltraverse, themodel should looklike the one in theimage.The assembly isnow ready in orderto proceed with theProperty andMaterial Validationof the model.3. Property and Material Validation3.1. Prepare the PropertiesAt this step the assignment of the correct Material and Thickness value is made for each Property. Use the following table to assign to the Properties the right names as they appear, a valid thickness and a Material with the given name.Material NameProperty Name ThicknessFront_Plates 2.7St34Outer_Left_Rail 1.5St37Outer_Right_Rail 1.5St37Inner_ Right _Rail 1.5St37Inner_ Left _Rail 1.5St37Cylindrical_Traverse8St34Front_Traverse3St34Traverse_Plates 3.5St34Top_Side_PBAR_Property-Top_Side_PBAR_MatBottom_Side_PBAR_Property-Bottom_Side_PBAR_MatIn order to quickly assign some of the above values, advantage of the modify functionality that is available in all lists can be taken. For example, the 1.5 thickness value can be assigned to the four Properties of the two box beams in one shot:-Mind having included a column for the thickness (“T1”) in the Properties list window.-Select the properties whose thickness will be modified.-Right-click on the “T1” column header.-Left-click of the <modify> field, type the new value and press ENTER.3.2. Input the Material DatabaseHaving prepared the Properties and the Material Names, the Material Database should be input.Open the Material Database, by applyingMaterial DB>List in the MATERIAL listwindow.The Material Database window appears, andthere are no Materials inside. Use the ‘ReadDB’button, with the option ‘From File(s)’, toinput a new Material Database. Navigatethrough the File Manager and select the file[material_database.key].As soon as the *.key file is selected you cansee in the ‘Material Database’ window theinput Materials.3.3. Update the Materials through the Material DatabaseHaving input the appropriate Materials through the Material Database, you are ready to use them in the model. This will be achieved through the functionality of the ‘Copy to List’ button in the‘Material Database’ window.Select all the Materials to be highlighted in thelist and press the ‘Copy to List’ button with theoption ‘Update by NAMEs’. This option willcopy the selected Materials in the M.LISTtaking into account their Names. A cross checkis taking place between the selected materialsof the MATDB and the M.LIST materials. In thecase that a material with the same Name isfound in the M.LIST, its ID remains intact andits fields are updated by the MATDB Material’sfields.The ‘COPY TO M.LIST PARAMETERS’ window appears providing options to overwrite or not the ‘comments’, ‘colors’ and/or‘unmatched’ of the MATDB Materials to the M.LIST Materials.Press OK to confirm.A report of the actions taken is given in theAnsa Info Window.NOTES:- It is very important to ensure that the names of the Materials in Material List have been assigned correctly in the previous step, since for the Update by Name procedure the Material names in the model have to beexactly the same as the ones in the MATDB.MASSSet4. Mass Definition4.1. Additional Mass to the structure In this step some additional masses will be added to the whole structure.Firstly, a mass of 60 kg will be added to the cylindrical traverse.Activate the ELEMENT>MASS>Set function of the LS-DYNA DECK menu. The ‘SETS HELP ’ window appears. This means that for this action a set should be created, on which the mass will be defined. Press the ‘NEW ’ button of the ‘SETS HELP’ window.The ‘Modifying SET:...’ window appears. Select the ‘PROPERTY ’ and pick the cylindrical traverse from the screen. The Property is highlighted. Press middle mousebutton to finish selection.The ‘SET ’ entity card appears. Give a name to the set, that should be easy to distinguish and press ‘OK ’.The set is now created and ready for use. Double click on its name in the ‘SETS HELP ’window, to select it.The Parts Manager appears in order to select in which Part the mass is going to belong.As soon as a Part is selected, the ‘MASS ’ entity card appears. Give an appropriate Name to the entity.In the ‘TYPE ’ drop down menu select the option ‘ADDMASS ’ and in the 'MASS ' field input a value of 60.Press OK to confirm.Proceed in the same manner to create a mass of type ‘ADDMASS’ and amount of 390 kg, assigned to the rest of the structure. That means that a new SET has to be created that will contain the following Properties. (“Outer_Left_Rail”, “Inner_Left_Rail”, “Outer_Right_Rail”, “Inner_Right_Rail”, “Front_Plates”, “Front_Traverse”, “Bottom_Side_PBAR_Property”, “Top_Side_PBAR_Property”).NOTES:- To visualize the generated element massmind to enable the visibility flag of thecorresponding entity (MASS) in the DatabaseBrowserIMPACTOR5. Adding the Barrier5.1. Input and position the Barrier.For the input and positioning of the barrier which is essential for the crashanalysis, you will use the IMPACTOR tool of the LS-DYNA DECK menu.Activate the AUXILIARIES>IMPACTOR function of the LS-DYNA DECK menu.The ‘IMPACTORS ’ window appears. Press the ‘NEW ’ button to begin the procedure.The ‘Impactor positioning ’ window appears where all the essential information can be defined.Enter a name next to the ‘Impactor ’ field. Press the ‘Browse ’ button next to the ‘file ’ field to select the appropriate file. Navigate through the File Manager and select the [barrier.key ] file.Press the ‘Browse ’ button next to the ‘set ’ field to define a set for the ‘Body ’.The ‘SETS HELP ’ window appears where by pressing the ‘NEW ’ button a new set can be created. Create a set containing all the Properties of the structure and give anappropriate name. Double click to select that set.In the ‘Initial Rotation Options’ drop down menu select ‘plane to plane ’. Impactor plane should be set as xmin and body plane as xmax .In the ‘Initial Translation Options’ drop down menu select ‘overlap, height ’, and input: ‘overlap=1.05’ and ‘height=50’.All these definitions will position the barrier to the right position according to the model.Press ‘OK ’ button.The barrier is positioned and the model should look like in the picture below.The IMPACTOR function places the barrier to the desired position by creating the appropriate DEFINE_TRANSFORMATION_/ keyword. This transformation is defined on an ‘Include’ file (the imported barrier.key).SPCSet6. Definition of FE-model EntitiesIn this section the rest of FE-model entities that are essential in this crash analysis are defined. 6.1. Define the Boundary Conditions.Two kinds of Boundary Conditions are needed for the analysis. One to fix the barrier at its position,and one to allow only x-directional movement for the structure.6.1.1. Boundary Conditions for the barrierActivateBOUNDARY>SPC>Setfunction of the LS-DYNA DECK menu.The ‘SETS HELP ’ window appears. Press the ‘NEW ’ button to create a new set. Use the Feature Angle selection tool for assistance, and create a set with the shell elements of the back of the barrier as shown in the image.Middle click to finish the selections. Give to the set a name and press ‘OK ’ to create it. Double click on it to use it for the Boundary Condition.The ‘BOUNDARY_SPC ’ card appears. Make sure that in the field ‘c ’, where the degrees of freedom are defined, all DOFs are fixed e.g 123456. Give a Name and press ‘OK ’ to create the Boundary Condition.The Boundary Condition has been created and you can visualize it by activating thecorresponding keyword (BOUNDARY_SPC) in the Database Browser.VELOCITYSet6.1.2. Boundary Conditions for the structureIn the same manner proceed to define the boundary conditions for the structure. The target is to constrain the two box beams in such way that their move will follow the x-direction. For the creation of theBOUNDARY_SPC use a set containing only the end nodes of the box beams, as shown in the image.Finally, in the BOUNDARY_SPC card define all dofs, except translation in x-axis, to be fixed e.g 23456.6.2. Define the Initial VelocityThe initial velocity for this analysis will be of amount 12 mm/ms (43.2 km/h) and will be applied onall nodes of the structure.For the definition of the Initial Velocity a set containing all the nodes of the structure is needed.Activate the INITIAL>VELOCITY>Set function of the LS-DYNA DECK menu. The‘VELOCITY ’ card appears. Type a question mark (?) inside the 'NSID ' field and select the set containing all the Properties of thestructure as it was created in previous step.The ‘VELOCITY ’ entity card is now updated with the appropriate set. Input a Name and fill the proper field with the amount of 12mm/sec. Press ‘OK ’ to confirm.LOADSet6.3. Define the GravityIt is essential for this analysis to define the existence of gravity. This is achieved through the definition of an acceleration applied on all nodes of the structure.For the definition of the Gravity, a new set containing all the nodes of the structure and the barrier will be used.Activate the LOAD>LOAD>Set function of the LS-DYNA DECK menu. The ‘SETS HELP ’ window appears. Create a new set containing all the nodes of the structure and the barrier. Name the set accordingly and proceed by a double click on it.In the ‘LOAD ’ entity card that appears, give a Name. Now a curve according to which the acceleration will be applied has to be defined. Type a question mark (?) inside the 'LCID ' field. The ‘DEFINE_HELP ’ window appears where you can select an already defined curve, if any, or create a new one. Press the ‘NEW ’ button to create a new curve.A new curve is generated and you can edit its points, name, etc. Name it accordingly and edit its points as it is shown in the image. Press‘OK ’ button to accept it.The curve is created and listed in the'DEFINE_HELP' window. Double click on it toselect it.The 'LOAD' card is now updated. In the 'SF'field input the value -1 to reverse the directionon which the load is applied, and according tothe 'DOF' field the direction should be in the Zdirection.Press OK to confirm.NOTE:- While defining the curve, It is crucial to inputsuch a value in the x-axis (e.g. time) that willbe equal or greater to the total analysis time,since the gravity must exist throughout thewhole solution.6.4. Define the ContactsTwo kinds of contact must be defined. One ‘self’ contact for the whole structure, andone contact for the structure against the barrier.Activate the AUXILIARIES>CONTACTfunction of the LS-DYNA DECK menu. The‘CONTACTS’ window appears. There arealready two contacts listed in the window, onecreated by the realization of Seam Lines, andthe other is the self contact of the barrier whichwas predefined along with the barrier itself.Press the ‘NEW’ button and select the ‘SingleSurface’ option from the drop down menu.The ‘CONTACT’ entity card appears.Define a set for the self contact definition.Type a question mark (?) inside thecorresponding field (SSID). The ‘SETS HELP’window appears. Select the set containing allthe Properties of the structure as it wasdefined in previous step. Double click on thenewly created set to update the field in the‘CONTACT’ entity card.Make sure that the TYPE of contact is set toAUTOMATIC_SINGLE_SURFACE and theSSTYP is set to 2:Part Set.Press ‘OK’ to create the contact.CONTACTDATABASECROSS_SECTIONThe ‘CONTACTS ’ window remains open. Being still in the function proceed in the same manner to create a ‘Surface to Surface ’contact. Press the ‘NEW ’ button and select the 'Surface to Surface ’ option from the drop down menu. The ‘CONTACT ’ entity card appears. For this type of contact two sets are needed, the master and the slave set.Type a question mark in the ‘SSID ’ field, which corresponds to the slave set. The ‘SETS HELP ’ window appears. Either select apreviously defined set (e.g. the one created in the previous step) or again create a new one. Select the previously defined set that contains the whole structure to update the field in the ‘CONTACT ’ entity card. Now type again a question mark in the ‘MSID ’ field, whichcorresponds to the master set. Proceed to the creation of a set containing the Shell Property of the barrier, and double click it to update the field in the ‘CONTACT ’ entity card. Make sure that the TYPE of contact is set toAUTOMATIC_SURFACE_TO_SURFACE and the SSTYP and MSTYP are set to 2:Part Set. Press ‘OK ’ to create the contact.6.5. Define Cross Sectionsof the cross sections use the CROSS_SECTION Assistant tool. This tool works in a stepwise wayand leads in the creation of a cross section consisting of nodes and elements.Activate theAUXILIARIES>DATABASE>CROSS_SECTION>A ssistant function of the LS-DYNA DECK menu. The ‘SECTION ASSISTANT ’ window displays the first step, which prompts to select the type of cross section. Select ‘PLANE ’ and proceed by pressing the ‘Next ’ button.In the next step define what type of entities(elements or properties), the plane is going to cut, and sequentially select those entities. Choose ‘Properties’ and select from the screen the Cylindrical Traverse Property. The traverse ishighlighted. Proceed by pressing the ‘Next ’ button.In this step define a plane which will be used to cut the previously selected Property. Select on the screen 3 points to define a plane parallel to the z-x plane. By selecting the 3rd point, Section Assistant automatically moves to the next step where visualization of the cutting plane appears.Move the Cutting Plane ifneeded to a desiredposition by using the – and+ buttons. Activate also the‘global_coord’ option. PressFinish to close the'SECTION ASSISTANT'window.The ‘DATABASE CROSS SECTION’entity card appears. Press the ‘OK’ buttonto create the Cross Section.By pressing ‘OK’ the function of CROSSSECTION Assistant is still active. Proceedin the same manner to define more CrossSections. To visualize the created CrossSections, activate the corresponding flagin the Database Browser.DATABASEHISTORY_OPTIONProceed with the creation of three more Cross Sections as shown in the image.NOTES:- Note that when a Cross Section is needed only on some elements of a Property, at the 2nd step selection of the option ‘Elements’ instead of ‘Properties’ can be made.6.6. Add Time History Output DefinitionsAt this point some Time History Output Definitions on nodes and/or elements can be added. Time histories of the selected nodes or elements will be stored according to the time interval specified on the Output Parameters Control Cards.6.6.1. Time History Output Definitions on NodesActivate the DATABASE>HISTORY_OPTION function of the LS-DYNA DECK menu. The ‘DATABASE ’ window appears listing all the Time History Output Definitions if any. Press the ‘NEW ’ button and select the‘DATABASE_HISTORY_NODAL>DATABASE _HISTORY_NODE(ID)’ option from the drop down menu. Time History Output Definitions on node will be created.buttonopens. Input a name and press 'OK'.corresponding flag in the Database Browser.In the same manner proceed to define three more Time History Output Definitions on the nodes as the following picture shows.6.6.2. Time History Output Definitions on ElementsActivate the DATABASE>HISTORY_OPTIONfunction of the LS-DYNA DECK menu. The‘DATABASE’ window appears listing all thepreviously defined Time History OutputDefinitions. Press the ‘New’ button and selectthe‘DATABASE_HISTORY_ELEMENT>DATABASE_HISTORY_BEAM(ID)’ option from thedrop down menu. Time History OutputDefinitions on beams will be created.Select the beam elements shown highlightedin the image. Confirm end of selection with themiddle mouse button.The ‘DATABASE_HISTORY_ELEM’ entitycard appears. Input a name and press ‘OK’ toconfirm.7. Definition of Control ParametersAn already defined Header [Control Parameters] can be imported and assigned to the current model. This allows the user to examine the Control cards and modify them if necessary.Activate the FILE>INPUT>LS-DYNA function of the main menu, to read in the available file [header.key ]. The contents of the file are shown below.Note that the imported Control Cards append or overwrite the existing options. The result is a combination of the current and the imported cards where in case of common cards the current options are overwritten. In the current model only the default control cards are activated.Use the AUXILIARIES > CONTROL > CONTROLS function to modify the control cards according toyour needs.CONTROLS CONTROLCHECK8. Final Steps8.1. Clearing unused entities of the modelActivate the File>Clear function. The ‘Compress ’ window appears where specific unused entities can be selected to be deleted.By pressing ‘OK ’ button, a report is generated in the ‘Ansa Info Window’ informing the user of the entities that have been permanently deleted.8.2. Checking the integrity of your model A very essential step before exporting the *.key file is to apply some checks to the model. ANSA performs a series of internal checks to the validity of input values withinentity cards. Moreover, the CHECK function may be used in order to identify errors arising from the improper application of constraints or other components of a model. These checks take into account the LS-DYNA solver limitations, constraints and rules that are applied during the initialization of the model.Activate the D.UTIL>CHECK>MODEL DATA function to activate a check, which verifies the correctness of model entities and identifiesany failed elements so as to be fixed.The MODEL DATA check identifies all errors related to the consistencyof the model with regard to the currently active Deck. At the end of the procedure, the ‘Checks ’ window appears listing all entities that fail the check. With the aid of this list, each of the identified errors can be fixed.Activate the D.UTIL>CHECK>UNDEFINED function to perform acheck, which identifies materials and properties in the whole database (M.LIST and PR.LIST) with ‘undefined’ state (DEFINED=NO in therespective card). These materials and properties are not written in theoutput file. The results are reported in a ‘Checks ’ window, where in theright click pop-up menu a ‘Fix’ option exists. To fix, choose to direct switch materials to DEFINED.Activate the D.UTIL>CHECK>CONTACTS > WHOLE MODEL function to check the contactdefinitions integrity by means of their sets andprojection distance. Penetration check is also performed between the elements participating inthe contacts sets. The results are reported in the ‘Checks ’ window.CHECKMODEL DATA CHECKUNDEFINED SELECT FROM LIST WHOLE MODELCHECKCONTACTS。

LS_DYNA软件个人学习总结

LS_DYNA软件个人学习总结LS_DYNA软件个人学习总结1、单位制：在DYNA动力学分析软件中，我们一般使用的单位制为(mm、mg、ms)。

即：mm mg ms m/s mN kpa g/cm3 mJ2、在DYNA中我们涉及到接触时，一般选择自动单面接触，次接触自动判断接触部分，如果为壳单元此接触自动考虑壳后，因此在建模时，注意留有间隙。

此外，对于单面接触，程序不会输出界面力，需要设置一个力的传感器*CONTACT_FORCE_TRANSDUCER_PENALTY 来定义，将从面设置为你所需要得到接触力的部件，一般只用定义一下ssid（salve set id)， sstyp(salve set type)，同时在用*DATBASE_RCFORC来输出。

就可以得到了接触力了。

此方法一般用来输出接触力以及刚体所受反力。

3、关键字*mat_add_erosion注意：excl为排除关键字，这个数字可以任意定义，如果某个参数对应的失效准则与此相同，则此准则就会被忽略。

几乎所有的力学软件都有统一规定：静水压以压为正、拉为负；所以对于静水压破坏准则就是给出最大静水压应力，如果大于该值，则材料破坏。

相反，应力则是以拉为正，压为负，所以拉应力破坏准则就是给出最大拉应力，如果拉应力大于该值，则材料破坏。

4、输出损伤变量3、LS-DYNA求解中途退出的解决方案LS-DYNA在求解过程中由于模型的各种问题常发生中途退出的问题，归纳起来一般有三种现象：一是单元负体积，二是节点速度无限大，三是程序崩溃。

单元负体积：这主要是由于人工时间步长设置的不合理，调小人工时间步长可解决该问题。

还有就是材料参数和单元公式的选择合理问题。

节点速度无限大：一般是由于材料等参数的单位不一致引起，在建立模型时应注意单位的统一，另外还有接触问题，若本该发生接触的地方没有定义接触，在计算过程中可能会产生节点速度无限大。

程序崩溃：该现象不常发生，若发生，首先检查硬盘空间是否已满，二是检查求解的规模是否超过程序的规模。

LS-DYNA常见问题汇总10DOC

LS-DYNA常见问题汇总1.0资料来源：网络和自己的总结yuminhust2005Copyright of original English version owned by relative author. Chinese version owned by /Kevin目录1.Consistent system of units 单位制度 (2)2.Mass Scaling 质量缩放 (4)3.Long run times 长分析时间 (9)4.Quasi-static 准静态 (11)5.Instability 计算不稳定 (14)6.Negative Volume 负体积 (17)7.Energy balance 能量平衡 (20)8.Hourglass control 沙漏控制 (27)9.Damping 阻尼 (32)10.ASCII output for MPP via binout (37)11.Contact Overview 接触概述 (41)12.Contact Soft 1 接触Soft=1 (45)13.LS-DYNA中夹层板(sandwich)的模拟 (47)14. 怎样进行二次开发 (50)1.Consistent system of units 单位制度相信做仿真分析的人第一个需要明确的就是一致单位系统(Consistent Units)。

计算机只认识0&1、只懂得玩数字，它才不管你用的数字的物理意义。

而工程师自己负责单位制的统一，否则计算出来的结果没有意义，不幸的是大多数老师在教有限元数值计算时似乎没有提到这一点。

见下面LS-DYNA FAQ中的定义：Definition of a consistent system of units (required for LS-DYNA):1 force unit = 1 mass unit * 1 acceleration unit1 力单位＝1 质量单位× 1 加速度单位1 acceleration unit = 1 length unit / (1 time unit)^21 加速度单位= 1 长度单位/1 时间单位的平方The following table provides examples of consistent systems of units.As points of reference, the mass density and Young’s Modulus of steel are provided in each system of units. “GRA VITY” is gravitational acceleration.2.Mass Scaling 质量缩放质量缩放指的是通过增加非物理的质量到结构上从而获得大的显式时间步的技术。

LSDYNA壳单元沙漏

壳单元技术的历史
第一次发布的Hughes-Liu壳单元速度慢的几个原因 : . 2 x 2 选择简化积分点selective reduced integration . 无向量化 (慢8倍) . 中间步的应变计算加速来自： . 1 点积分 . n + 1 几何形状用于应变计算 . 使用总体坐标系增加粘性沙漏力控制零能模式
相对速度.应变的共轭应力是 Cauchy 应力
壳运动假定节点是 co-planar.
坐标选择坐标系构造单元坐标系
Belytschko-Tsay 壳这种壳作为Hughes-Liu 壳的考虑计算效率的替代公式
. 用 5个积分点， B-T 壳要求 725个数学操作步，而 H-L 壳需要 4066. . Selectively reduced (S/R) 积分的 H-L壳要求35,367 由于它的计算效率， B-T 壳为常用的单元公式，也因此成为4节点壳单元公式的缺省公式
积分点平面内
•加速度，速度和位移在节点求值
•应力和应变在积分点求值
全积分
积分点
- 计算效率高
- 沙漏
壳单元公式膜单元
全积分
5. Belytschko-Tsay membrane 9. Full integrated Belytschko-Tsay membrane 三角形单元
6. S/R Hughes-Liu 7. S/R co-rotational Hughes-Liu 16. Bathe-Dvorkin features in B-T 简化积分
壳单元的特性
有限应变厚度方向积分点的任意和固定壳单元厚度更新单元卡上几何特性可任意指定全矢量或平行的 Fully vectorized and parallelized. 所有壳单元共享的构造子程序可使用共同的局部坐标系沙漏控制来控制零能模式

LS-DYNA显式时间步长与沙漏控制

基于面段的接触(SOFT=2)
• SOFT=2接触增加的选项
– SBOPT在可选的卡片A中 2（默认）：假定为平面面段 3：可考虑面段的翘曲 4：滑移选项 5：使用选项3和4
– DEPTH在可选的卡片A中
2（默认）：检查面段穿透 3：同2，但穿透深度同时在面段边缘检查 5：同2，同时增加边－边穿透的检查
• 有时使用隐式分析是一种高效的方法
终止控制
• *CONTROL_TERMINATION
– 指定时间或循环（时间步）终止 – 当时步＝初始时间步长的某个小数时终止 – 能量变化达到某个百分数时终止 – 质量变化（仅用于使用质量缩放的求解）达到某个百分
数时的终止
• *TERMINATION_<option>
基于面段的接触(SOFT=2)
• 忽略初始穿透
– 有初始穿透的节点在分析开始的时候不被移动 – 面段的初始穿透量会被存储起来，在计算接触力的时候，要从当
前的穿透量中减去初始的穿透量作为接触力计算的穿透量 – 这种方法一直贯穿在整个分析中，因此，如果一个在开始计算时
未被检测到的穿透节点在第一次检测到穿透时不会因为很大的接触力而产生巨大的速度 – 所谓的“shooting node logic” 参数SNLOG对此接触没有影响 – 当参数IGNORE设置成1时对SOFT=0或1的初始穿透会作同样的处理
• 对壳单元，体单元和厚壳单元是基于惩罚的接触算法 • 刚度计算和SOFT=1采用相同的方式（基于稳定性原则） • 穿透搜索采用独特的方法 • 该选项不能用于梁接触或节点到面的接触 • 运用
– 常规方法定义接触 – 在可选卡片A中，设置SOFT=2 • 970以前的版本不能用MPP
基于面段的接触(SOFT=2)

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Ls_dyna 沙漏控制考试试题
一、选择题
1、沙漏能影响和以及单元，但不能影响三角形壳单元和梁单元。

A、实体单元
B、四边形单元
C、一维单元
D、二维单元
2、一般情况下，如果沙漏能量超过总能量的，那么就需要调整沙漏控制，以保证计算结果的精度。

A、10%
B、15%
C、20%
D、25%
3、沙漏模式是一种非物理的变形模式，产生零应变和应力。

A、超能
B、零能
C、刚性
D、柔性
4、如果系统计算沙漏能并将其输出，必须设置关键字*CONTROL_ENERGY中的控制参数HGEN = 。

A、2
B、3
C、4
D、5
5、在*SECTION_SHELL中，没有沙漏模式的壳单元公式和。

A、1
B、2
C、6
D、7
6、如果不考虑计算成本，使用单元的方法，可以有效地控制沙漏现象。

A、全积分
B、单点积分
C、缩减积分
D、选择性缩减积分
7、在关键字*CONTROL_HOURGLASS全局控制沙漏中，QH一般取值范围之间，如果超过这个范围将引起计算不稳定。

A、0—0.05
B、0.05—0.15
C、0.15—0.20
D、0.20—0.25
8、如果需要针对每个PART单独控制，需要定义关键字。

A、*PART
B、*CONTROL_HOURGLASS
C、*CONTROL_ENERGY
D、*HOURGLASS
9、在关键字*HOURGLASS中设定沙漏系数是项。

A、IBQ
B、QM
C、Q1
D、Q2
10、在Ls_dyna关键字*CONTROL_HOURGLASS全局控制沙漏中，QH默认值是。

A、0.1
B、1
C、0.01
D、0.001
选择题参考答案：
1、ABD
2、A
3、B
4、A
5、CD
6、AD
7、B
8、D
9、B 10、A
二、有限单元单点积分方法可以大幅度降低计算成本，但容易沙漏模式，产生一种自然振荡并且比所有结构响应的同期短得多。

沙漏变形没有刚度并产生锯齿形
外形，由此使计算结果不正确。

请回答有哪些方法可以有效地控制沙漏现象？参考答案：
控制沙漏现象的方法：
1、使用均匀网格，避免在单点上集中加载；
2、调整模式的体积粘性；
3、使用单元的全积分方法；
4、增加模型的弹性刚度；
5、局部增加模型刚度；。