Solver Setting-Equilibrium 针对“Lock Up”问题的解决方法！

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针对静平衡求解过程中出现"Lock Up"问题的解决方法

Solver Settings - Equilibrium
Error
Specifies the maximum relative displacement error allowed during static simulations.
The default is 1.0E-04 and the range is Error > 0
定义静平衡求解过程中的位移相对误差；
此数值越大求解越容易收敛，自然误差也越大。
Tlimit
Specifies the maximum translational increment allowed per iteration during static simulations performed using static simulations.
The default is 20 and the range is Tlimit > 0
定义静平衡求解过程中，每一步迭代的最大位移增量；
对于复杂模型，若位移增量过大，受力的突变会导致静平衡求解失败；
Alimit
Specifies the maximum angular increment allowed per iteration. The default units for Alimit are radians. To specify Alimit in degrees, add a D after the value.
The default is 0.17453 (10 D) and the range is Alimit > 0
与Tlimit相似，需要注意的地方是默认单位是“弧度”，若需要输入“度”，必须在数值后面加“D”。如需要设置为10度，输入为10D
Maxit
Specifies the maximum number of iterations allowed for finding static equilibriums.
The default is 25 and the range is Maxit > 0.
最大迭代步数，应该与Tlimit和Alimit配合设置；
假设初始状态与平衡状态的位移相差100mm，而Tlimit设置为1，则Maxit需要设置比100大，设置为200应该差不多了。
Stability
Specifies the fraction of the mass and damping matrices ADAMS/Solver adds to the stiffness matrix. Adding a fraction of the mass and damping matrices to the stiffness matrix can stabilize the iteration process and prevent the iteration from diverging. Often the stiffness matrix is singular for a system because the system is neutrally stable (for example, the system moves in certain directions without affecting the potential energy). Adding a fraction of the mass and damping matrices to the stiffness matrix removes this singularity and makes it possible to solve for equilibrium positions. The value of Stability does not affect the accuracy of the solution, but it does affect the rate of convergence of the iteration process.
The default is 1.0E-05 and the range is Stability 0.
施加于刚度矩阵的一个“稳定系数”，使迭代过程更加平稳，更容易收敛；
此数值不影响求解精度，理论上越大使迭代越容易收敛，但越大会使求解越慢。
Imbalance
Specifies the maximum force imbalance allowed during static simulations performed using static analyses.
The default is 1.0E-04 and the range is Imbalance > 0.
个人理解为与ERROR是相类似的，此处为力的误差;
此数值越大求解越容易收敛，自然误差也越大。

以上各数值，ERROR、Imbalance对求解精度是有影响的，不宜设置过大；.
Error、Imbalance设置越小，Tlimit、Alimit需要设置得越小，Maxit需要设置得越大，求解时间越长；
Tlimit、Alimit与Maxit要配合使用；
Stability根据实际情况设置；
Maxit影响求解失败前的求解次数，Stability影响求解速度。
正确的设置，可以在效率与精度之间得到一个平衡点！

以下是对求解过程的非专业理解：

下图是对于带有前、后板簧的三轴卡车设置参考：



以上纯属个人非专业理解，如有错漏之处，请指出，谢谢,,,

原文出处：http://bluestar179.blog.163.com

liuleilei77

回去好好想想啊

小王

经典，包包学长到底是高手！

wangjunjie0536

各个模块中的设置选项是不是不一样啊，好像RAIL中只有前面几项，静平衡问题很头疼，不知道各位高手有没有什么比较好的方法，求指教！

baopu

呵呵，正好有用，又看到你的文章了

advancej

很实用，谢谢楼主！

q410461917

Reading in property files...
Reading of property files completed.
Setting up assembly for analysis of loadcase: 'parallel_travel'...
Writing analysis information to Adams/Solver command file: 'etr_parallel_travel'.
Simulation(s) are beginning...





   *********************************************************************
   *                                                                   *
   *                      MSC.Software Corporation                     *
   *                                                                   *
   *                             A d a m s                             *
   *                                                                   *
   *          Automatic Dynamic Analysis of Mechanical Systems         *
   *                                                                   *
   *                      A d a m s / S o l v e r                      *
   *                                                                   *
   *      2011-04-15 08:46:26              Version MD R3               *
   *                                                                   *
   *      Customer Entitlement ID:         085609A7-894A437E           *
   *                                                                   *
   *********************************************************************
  

   Enter ADAMS model file name or Carriage Return or ? (or STOP):

   

   No model input file (ADM file) is given.
  

   Enter Command:

   file/model=etr_parallel_travel

   A new model supplied.  Initialization starts...
  
   The default input and analysis values will be restored.
  

   CPU time used = 7.81250E-02 seconds

   Enter ADAMS model file name or Carriage Return or ? (or STOP):

   Enter ADAMS output file name or ? (default is same as input):

     Adams model file .. etr_parallel_travel.adm

  
   Default file names for output files
  
     Tabular output file:
     etr_parallel_travel.out
  
     Diagnostic file    :
     etr_parallel_travel.msg
  
     Message Database file    :
     etr_parallel_travel.mdb
  
     Graphics file      :
     etr_parallel_travel.gra
  
     Request file       :
     etr_parallel_travel.req
  
     Results file       :
     etr_parallel_travel.res
  

   Input Phase - Reading in Model
  

   ***********************************************************
   Adams/Solver dataset Title:
   Adams/Car Assembly (MD Adams R3)
   ***********************************************************

   Reading of model complete.
  

   Adams/Car MD Adams R3

Processing ENVIRONMENT entries in 'd:\MSC.Software\MD_Adams\R3\acar/acar.cfg'
Processing ENVIRONMENT entries in 'C:\Documents and Settings\Administrator/.acar.cfg'
   
   =================================================================
                              Adams/Tire
                          Version MD Adams R3
   =================================================================

   Input Phase - Populating Solver database
  

   Input Phase Complete.
  

   CPU time is 7.81250E-02 seconds.
   
   acar_2008.1.0/ac_scc_init
   
       Reading ARRAY parameters using the
       ADAMS/Car array statement definitions.
   
   acar_2008.1.0/ac_scc_init
   
       Checking ARRAY parameters...

   Input and Input Check Phase complete.

   The system has 33 kinematic degrees of freedom.

   Enter Command:

   preferences/solver=F77

   Enter Command:

   control/ routine=acarSDM::con950, function=user(950,29,31,1,2,17,19,1,3,2,3,28,30,2,3,28,30,1,1)

   Entering the static equilibrium analysis phase...

   Displacement initial condition analysis...

  
   Jacobian Matrix Statistics for the Initial Conditions
   ======================================================
   Number of equations ............. = 219
   Number of non-zero entries ...... = 1196
   Percentage of matrix non-zero ... = 2.4937
   Total space used in MD array .... = 221782
  

Reading configuration file 'd:\MSC.Software\MD_Adams\R3\acar/acar.cfg'
Reading configuration file 'C:\Documents and Settings\Administrator/.acar.cfg'


   Performing Static analysis...

   Generating the Jacobian matrix for the statics or quasi-statics problem.

  
   Jacobian Matrix Statistics for Statics
   ======================================================
   Number of equations ............. = 581
   Number of non-zero entries ...... = 4912
   Percentage of matrix non-zero ... = 1.4551
   Total space used in MD array .... = 305394
  

---- ERROR ----
   Attempt = 1. No convergence after 1000 iterations. Best iteration = 1000.
   Trying next attempt with a different set of statics parameters...
  

   For the last attempted iteration the equation with the largest error
   was PART etr_parallel_travel.my_macphenson_20110414.gel_strut  Error = 4.18003E+06
  
   The variable receiving the largest increment
   was PART etr_parallel_travel.my_macphenson_20110414.gel_wheel_carreir  Delta = 9.810E+05

---- ERROR ----
   Static equilibrium analysis has not been successful.

   Restoring the input initial conditions...

---- ERROR ----
   Initial Static Sim. Not Successful

   Terminating Adams/Car usersubs...

  
      Adams/Solver execution terminated by subprogram ERRMES
  

   CPU time used = 4.7969 seconds
Analysis failed!
Please check the error messages to determine the cause.

q410461917

楼主，按照你的要求改了，怎么还是没作用呢？？

q410461917

自己建的麦弗逊式前悬挂．仿真出现以上问题．
如果调用POwertrain模板进行仿真，没问题．
请问楼主，这如何是好呢？

q410461917

问题已解决，模型错误．．

seefar

没学到家啊，怎么也看不懂啊

liehuo11

q410461917 发表于 2011-4-15 08:59
问题已解决，模型错误．．

我建立的模型也出现了你这样的错误，求解是哪里出现的错误啊  跪求指点·····谢谢

蜡笔的白

求解器问题一直困扰，多谢！

逆鳞1989

整楼好帖