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net (cumulative) strain on external walls - pressure housing

Hi, In related to a discussion I have started on this topic a couple of weeks back, Internally Pressurized Housing - Post Processing , here is another question I am hoping to get some answers. 

I modelled the housing with axisymmetric 2D elements in order to investigate the strain on the OD (along the "tube section"). I was able to pick the nodes using curve on the OD of the tube section and plot/import all the strain values for applied internal pressure of 20 ksi. Image below shows the axial strain plot along the tube section on the OD. Similarly I can grab the Azimuth and radial strains for the outer elements. 

 

Axial Strain_Tube_Along Length.png

 

But really what I am mostly interested to know is "the net external strain on the elements (on OD)". in other words, the net change in circumference/radius due to pressure. Is there a way I could accomplish this? I have attached the model for reference. 

 

Thank you. 

 

Ajinka

6 REPLIES

Re: net (cumulative) strain on external walls - pressure housing

After reading more, I think that the hoop strain on the OD is the cumulative (total)? the one that measures the change in circumference.!!?

Re: net (cumulative) strain on external walls - pressure housing

[ Edited ]

If I have understood correctly what do you need, you have to plot the total displacement and you will give the change in diameter!

 

Best Regards

 

AMinati

Re: net (cumulative) strain on external walls - pressure housing

Hi AMinati, Thank you. That should give me the change in diameter /circumference. 

 

Regards,

Ajinka

Re: net (cumulative) strain on external walls - pressure housing

The material tensile strengh is 40 kpsi (Yiled is probably just over half). The Von Mises stress on the ID is about 36 kpsi. Should I be worried? Can someone please enlighten me. Thank you. 

 

Von Mises Stress_2D Axisymmetric Elements_R.PNG

Re: net (cumulative) strain on external walls - pressure housing

[ Edited ]

"To plot stress I use the FEMAP Stress Linearization Tool (see Femap forum) to analyse stress according to ASME Section VIII Division 2" 

Dont worry, be happy)

Re: net (cumulative) strain on external walls - pressure housing

Thank you Smiley Happy