Viscoelastic and Plastic can not be defined as a combination in ABAQUS

yuanyao

Hello erveryone,

i want to simulate Polymere material, it needs elastic plastic and viscoelastic for relaxation behavier.
but ABAQUS can not set the combination of plastic and viscoelastic at the same time.
can i in step some material deactive and next step active?

Thanks

[ 本帖最后由 yuanyao 于 2007-1-18 01:00 编辑 ]

步行去远方

参考一下这些贴子, 看能不能达到你的目的.
http://www.simwe.com/forum/viewt ... 4%C1%CF%CA%F4%D0%D4
http://www.simwe.com/forum/viewt ... 4%C1%CF%CA%F4%D0%D4
http://www.simwe.com/forum/viewt ... 4%C1%CF%CA%F4%D0%D4

chunyu

可以使用在不同的步骤中使用不同的材料模型这一办法来模拟特定加载条件下的聚合物，比如你说的快速加载（弹塑性）和蠕变（粘弹性）。使用关键字import就可以实现这个功能。但是要研究一般载荷下的聚合物变形，可能就得开发粘弹塑性本构模型。已经有很多本构模型，比如比较简单的： Characterization of mechanical properties of polymers by nanoindentation tests, Philosophical Magazine,Vol. 86, No. 28, 1 October 2006, 4487–4506。这篇文章有一个简单的综述，还有一个简单的粘弹塑性模型。

yuanyao

thank chunyu and 步行去远方, I will try to use the first method in the step.

yuanyao

i have tried the field variable, it get also error in DAT

***ERROR: *VISCOELASTIC MAY NOT BE USED WITH ANY OF THE PLASTICITY OPTIONS
Sample Text

chunyu

This section may be of help--"Analysis manual-9.2.1 Transferring results between ABAQUS analyses: overview"

There is one limitation to use this technique, i.e., the assembly function cannot be used. In other words, if there are more than one part in the model, they have to be built together  and then partitioned into seperate  parts. To achieve this, the .inp file has to be modified as well. The keyword, *assembly, should be removed.

On another hand, it is true that to develop a UMAT is never a triavl task. However, once  it is finished, we can use it repeatedl with much ease.

FreddyMusic

Why not use POLYFLOW instead abaqus ?

http://www.fluentchina.com/prod_1_2.html

yuanyao

in Transferrring Results Between ABAQUS 7.7.3-11

the Assembly can also be transferred between Standard. I have tried and becomed such of error.
there is also instruction for CAE in 7.7.3.-1




  PROCESSING PART, INSTANCE, AND ASSEMBLY INFORMATION
   *******************************************************


***ERROR: Problem when parsing keyword: INSTANCE     Invalid parameter: 4. The
           parameter may be misspelled, obsolete, or invalid.
***NOTE: DUE TO AN INPUT ERROR THE ANALYSIS PRE-PROCESSOR HAS BEEN UNABLE TO
          INTERPRET SOME DATA.  SUBSEQUENT ERRORS MAY BE CAUSED BY THIS OMISSION

***ERROR: in keyword *IMPORT, file "Pre-load2.inp", line 22: The keyword is
           misplaced.

***ERROR: in keyword *ENDINSTANCE, file "Pre-load2.inp", line 23: The keyword
           is misplaced. It can be suboption for the following keyword(s):
           assembly

***ERROR: in keyword *ELSET, file "Pre-load2.inp", line 1975: The following
           sets/ids do not exist: "TUBUS K60 PHI4,4,8-1-1".1, "TUBUS K60
           PHI4,4,8-1-1".316609

***ERROR: in keyword *NSET, file "Pre-load2.inp", line 1163: The following
           sets/ids do not exist: "TUBUS K60 PHI4,4,8-1-1".1, "TUBUS K60
           PHI4,4,8-1-1".62814

***ERROR: in keyword *NSET, file "Pre-load2.inp", line 1977: The following
           sets/ids do not exist: "TUBUS K60 PHI4,4,8-1-1".46, "TUBUS K60
           PHI4,4,8-1-1".47, "TUBUS K60 PHI4,4,8-1-1".49, "TUBUS K60
           PHI4,4,8-1-1".51, "TUBUS K60 PHI4,4,8-1-1".52, "TUBUS K60
           PHI4,4,8-1-1".3226, "TUBUS K60 PHI4,4,8-1-1".3227, "TUBUS K60
           PHI4,4,8-1-1".3228, "TUBUS K60 PHI4,4,8-1-1".3229, "TUBUS K60
           PHI4,4,8-1-1".3230, "TUBUS K60 PHI4,4,8-1-1".3231, "TUBUS K60
           PHI4,4,8-1-1".3232, "TUBUS K60

***NOTE: Warning message is too long. It has been truncated.

***ERROR: in keyword *NSET, file "Pre-load2.inp", line 2544: The following
           sets/ids do not exist: "TUBUS K60 PHI4,4,8-1-1".1, "TUBUS K60
           PHI4,4,8-1-1".4, "TUBUS K60 PHI4,4,8-1-1".55, "TUBUS K60
           PHI4,4,8-1-1".56, "TUBUS K60 PHI4,4,8-1-1".57, "TUBUS K60
           PHI4,4,8-1-1".58, "TUBUS K60 PHI4,4,8-1-1".59, "TUBUS K60
           PHI4,4,8-1-1".60, "TUBUS K60 PHI4,4,8-1-1".61, "TUBUS K60
           PHI4,4,8-1-1".62, "TUBUS K60 PHI4,4,8-1-1".63, "TUBUS K60
           PHI4,4,8-1-1".64, "TUBUS K60 PHI4,4,8-1-1".65, "TUBUS K60

***NOTE: Warning message is too long. It has been truncated.

     END PROCESSING PART, INSTANCE, AND ASSEMBLY INFORMATION
   ***********************************************************

  *visco, cetol=0.5



     OPTIONS BEING PROCESSED
   ***************************


  *import, update=NO

     Element and node information will be imported at
         Step                 6
         Increment number     1
      of the specified ABAQUS/Standard analysis.

     The element state is to be imported.

     The imported configuration will not be updated.

     The elements in the following element sets
       are to be imported :
                                   ASSEMBLY_PRODUCT2-1-1__PICKEDSET7                                               
                                   ASSEMBLY_PRODUCT2-5-1__PICKEDSET25                                             

***ERROR: PRE WORKSPACE IS INSUFFICIENT. PRE_MEMORY IS CURRENTLY SET TO 256.00
           MBYTES. NO ESTIMATES OF THE REQUIRED MEMORY ARE AVAILABLE DURING
           INPUT FILE PROCESSING. PLEASE INCREASE THE VALUE OF PRE_MEMORY.





          THE PROGRAM HAS DISCOVERED     8 FATAL ERRORS

               ** EXECUTION IS TERMINATED **



                              END OF USER INPUT PROCESSING



     JOB TIME SUMMARY
       USER TIME (SEC)      =   24.520   
       SYSTEM TIME (SEC)    =   1.5300   
       TOTAL CPU TIME (SEC) =   26.050   
       WALLCLOCK TIME (SEC) =         50