ORPHAN MESH AND TIME PROBLEM 1

[Apocalyptica]

Hello everybody

I try brain injury in abaqus 6.13. I use for 3d modelling mimics software and 3 matic. ı make all brain parts from MRI in mimics and export to 3 matic for meshing. I do smoothing,reducing triangle etc. in 3 matic. then export to abaqus with orphanmesh. ı am doing assmbly, step, intreaction, bc,jop etc. in abaqus and run. ı use just abaqus interface but not phton ı am new in abaquse. my problem are

1. The abaqus run during 3 days in my computer but give no result yet.my step time is 0.006 s and dynamic\expclit(My computer is 64 bit 4 gb ram)if ı want to see visulation it said " this is no valid step data available on the database. if the anaysis is running, the databese must be closed and reopened once the results have been intialized.the requested operation has been cancelled"


2. There are warning about 5000 distorted element within milions elments and ı dont know what can ı do? ı cant remesh in abaqus, you think, do ı have to remesh increaising\decreasing in 3 matic again or can ı ignore this stuation.

3. when ı entered value of the brain possion ratio 0.49, the abaqus give warning "The poission ratio of 0.49 exceeds 0.48(so the bulk modul of 36.500 exceeds 25 times the shear moduls of 0.73490) however a hybrid type element is not used. this may cause convergence probblem" ...

What can ı do this situation why it takes a long time how can ı solve fastly this problem

My english is bad. excuse.

 

[Apocalyptica]

ANY İDEA?

 

[Peterleng]

Ok first of all you need to have sense with the data you just introduced, you think with a 4 GB ram computer its gonna be more than 3 days computing ? how many millions of elements did you mesh?

I dont have much experience in Abaqus either but i had the problem you just had several times. One way to know where is the problem is to analyze the info that appears on the "status" label when you open the monitor, depending that info, sometimes you can judge that if the calculations are going in the right way.

But in my experience when it doesnt let me open results and i cant see how the model is going, normally its because the construction of the model wasnt perfect... at the end when it finished i saw the results and those where totally wrong (i did mistake in the step or in the contact properties or something like that) So consecuences of this mistake : too much time calculating and wrong solution.

About the distorted elements, dont worry its a warning that its suposed to happen when a material suffer a critic strain due to stress or something like that. About the poisson ratio i would say to use the 0.48, its very close right ? data cant be very different

As i say i am a beginner too, so probably u may wait to read a more experienced answer.

 

[Apocalyptica]

thanks peterleng. ı solved all prob...

But there are another problem. when ı ımport orphanemesh from 3 matic to abaqus, which units do ı use, sı(m) or Sı(mm)? which one...

 

[Apocalyptica]

dear friends

there are wave speed problems with orphane mesh. how can ı fix it?