Question on how to apply pressure?

Mohd Azhan Fikry

Hello,

I am currently trying to simulate a pipe burst test simulation. The model will simulate pressure being applied to the inner wall of the pipe. The condition is that the pressure applied must increase linearly with time which is 60 kPa/s. I have checked all types of PLOAD that can be used but it seems there is no PLOAD that can be used as mentioned in the condition "pressure applied must increases linearly with time". Is there any way that I can apply pressure as per mentioned in the condition? Appreciate any help.

Thank you.

Alihan Alayoğlu_22549

Mohd Azhan Fikry said:

Hello, I would like to ask another question, for the step "Create pressure load on a load collector w no card image" how much pressure do i need to define? Do i define 0 MPa in the pressure as my pressure at zero seconds is 0 or do i define any value of pressure? Appreciate any help.

It depends on your problem. For example; you could create 10 bar pressure and define the table such this: (x=time , y=pressure ratio)

   x - y 

   0 - 0       (0x10=0 bar pressure at 0 second)

   1 - 0.1    (0.1x10=1 bar pressure at 1 second)

2.6 - 1       (1x10=10 bar pressure at 2.6 second)

   3 - 0.5    (0.5x10=5 bar pressure at 3 second)

3.3 - 5.6    (5.6x10=56 bar pressure at 5.6 second)

 

and you are able to switch between lineer and log scales for tabled1 card image in both x and y axis, individually.

 

I hope it helps and please don't forget to highlight as correct answer

 

Alihan Alayoğlu_22549

If there isn't any non-linearity in your system; you could use direct transient analysis procedure.

Create pressure load on a load collector w no card image

Define time vs load values in a TABLED1 load collector

Create TLOAD1 collector and select pressure load as exciteid and TABLED1 for TID to set the time dependency

Create TSTEP load collector to define time step (i.e. 300 time step (N) and 0.01 increment (DT) for a 3 sec total time )

Select TLOAD1 for DLOAD and TSTEP for TSTEP (time) in Transient (direct) load step

 

Please check this e-book https://altairuniversity.com/free-ebook-learn-dynamic-analysis-with-altair-optistruct/ out for more.

 

Mohd Azhan Fikry

Alihan Alayoğlu_22549 said:

If there isn't any non-linearity in your system; you could use direct transient analysis procedure.

Create pressure load on a load collector w no card image

Define time vs load values in a TABLED1 load collector

Create TLOAD1 collector and select pressure load as exciteid and TABLED1 for TID to set the time dependency

Create TSTEP load collector to define time step (i.e. 300 time step (N) and 0.01 increment (DT) for a 3 sec total time )

Select TLOAD1 for DLOAD and TSTEP for TSTEP (time) in Transient (direct) load step

 

Please check this e-book https://altairuniversity.com/free-ebook-learn-dynamic-analysis-with-altair-optistruct/ out for more.

 

Thank you for the suggestion. What if there is non-linearity in my system? Such as non-linearity in my materials.

Alihan Alayoğlu_22549

Mohd Azhan Fikry said:

Thank you for the suggestion. What if there is non-linearity in my system? Such as non-linearity in my materials.

Set analysis type as non-lineer transient and add NLOUT load collector, differently. Depending on your model and solver version; you could add param card and activate LGDISP=1 if needed.

Mohd Azhan Fikry

Alihan Alayoğlu_22549 said:

Set analysis type as non-lineer transient and add NLOUT load collector, differently. Depending on your model and solver version; you could add param card and activate LGDISP=1 if needed.

Thank you for the guide. Before that, does this fall under dynamic analysis or static analysis? I am new to this so I am still confused about certain things.

Alihan Alayoğlu_22549

Mohd Azhan Fikry said:

Thank you for the guide. Before that, does this fall under dynamic analysis or static analysis? I am new to this so I am still confused about certain things.

Transient means that there are changes in your system with respect to the time. This takes the dynamic effects like inertia and damping into account. Thus your analysis becomes dynamic. Read this for more;

https://feaforall.com/how-to-get-started-with-transient-fea-simulation/

https://www.youtube.com/watch?v=QdShij33teQ&t=1s

 

I offer you to read Altair's e-books starting with the practical aspect of FE simulation. These will enlarge your perspective to the FEA world. 

https://altairuniversity.com/free-ebooks/

All we were on the same road in the past. Please dont worry and keep going to ask. 

 

Mohd Azhan Fikry

Alihan Alayoğlu_22549 said:

Transient means that there are changes in your system with respect to the time. This takes the dynamic effects like inertia and damping into account. Thus your analysis becomes dynamic. Read this for more;

https://feaforall.com/how-to-get-started-with-transient-fea-simulation/

https://www.youtube.com/watch?v=QdShij33teQ&t=1s

 

I offer you to read Altair's e-books starting with the practical aspect of FE simulation. These will enlarge your perspective to the FEA world. 

https://altairuniversity.com/free-ebooks/

All we were on the same road in the past. Please dont worry and keep going to ask. 

 

Thank you for the advice and help

Mohd Azhan Fikry

Alihan Alayoğlu_22549 said:

Transient means that there are changes in your system with respect to the time. This takes the dynamic effects like inertia and damping into account. Thus your analysis becomes dynamic. Read this for more;

https://feaforall.com/how-to-get-started-with-transient-fea-simulation/

https://www.youtube.com/watch?v=QdShij33teQ&t=1s

 

I offer you to read Altair's e-books starting with the practical aspect of FE simulation. These will enlarge your perspective to the FEA world. 

https://altairuniversity.com/free-ebooks/

All we were on the same road in the past. Please dont worry and keep going to ask. 

 

Hello, I would like to ask another question, for the step "Create pressure load on a load collector w no card image" how much pressure do i need to define? Do i define 0 MPa in the pressure as my pressure at zero seconds is 0 or do i define any value of pressure? Appreciate any help.

Alihan Alayoğlu_22549

Mohd Azhan Fikry said:

Hello, I would like to ask another question, for the step "Create pressure load on a load collector w no card image" how much pressure do i need to define? Do i define 0 MPa in the pressure as my pressure at zero seconds is 0 or do i define any value of pressure? Appreciate any help.

It depends on your problem. For example; you could create 10 bar pressure and define the table such this: (x=time , y=pressure ratio)

   x - y 

   0 - 0       (0x10=0 bar pressure at 0 second)

   1 - 0.1    (0.1x10=1 bar pressure at 1 second)

2.6 - 1       (1x10=10 bar pressure at 2.6 second)

   3 - 0.5    (0.5x10=5 bar pressure at 3 second)

3.3 - 5.6    (5.6x10=56 bar pressure at 5.6 second)

 

and you are able to switch between lineer and log scales for tabled1 card image in both x and y axis, individually.

 

I hope it helps and please don't forget to highlight as correct answer

 

Mohd Azhan Fikry

Alihan Alayoğlu_22549 said:

It depends on your problem. For example; you could create 10 bar pressure and define the table such this: (x=time , y=pressure ratio)

   x - y 

   0 - 0       (0x10=0 bar pressure at 0 second)

   1 - 0.1    (0.1x10=1 bar pressure at 1 second)

2.6 - 1       (1x10=10 bar pressure at 2.6 second)

   3 - 0.5    (0.5x10=5 bar pressure at 3 second)

3.3 - 5.6    (5.6x10=56 bar pressure at 5.6 second)

 

and you are able to switch between lineer and log scales for tabled1 card image in both x and y axis, individually.

 

I hope it helps and please don't forget to highlight as correct answer

 

Thank you for the guidance and help.