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Acceleration load import

Fedra853

Hi!

I have an external text file containing: points of application x,y,z cordinates and relative x,y,z components of an accelaration that vary for each node. Something like this:

X1 Y1 Z1 A1x A1y A1z

X2 Y2 Z2 A2x A2y A2z

....

Xn Yn Zn Anx Any Anz

I need to import this values in hypermesh for a dinamic analysis.

If they are forces i can directly import that file, and mapping the acceleration point on the nearest model node. But whit accels this in not possible.

How can i import the file and associate the acceleration at the model nodes for running the analysis in Optistruct?

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Altair Forum User

Hi,

We are looking into this. We will get back to you soon.

Beta

Hi @Fedra853

you can try switch data types from ACCEL to ACCEL1. ACCEL1 allows you to specify acceleration on a node. then do the rest like it is Force

Fedra853

Hi @Toan Nguyen, and thanks for your reply!

The option that you suggest allows you to associate an acceleration to a node, but i have different acceleration for every node, tought, with this method, i have to import accelerations one by one and next find a way for associate the imported accels1 nodes to my model nodes.

With forces it's possible upload a file like the one above, and HM automaticly import and map the forces. I'm searching something like this.

Beta

Hi @Fedra853

Really? Could you please share the ways you do with the Force. I don't know about it

Altair Forum User

The option that you suggest allows you to associate an acceleration to a node, but i have different acceleration for every node, tought, with this method, i have to import accelerations one by one and next find a way for associate the imported accels1 nodes to my model nodes.

With forces it's possible upload a file like the one above, and HM automaticly import and map the forces. I'm searching something like this.

One work around which I can suggest is to create a .fem or .dat file with acceleration data in any text editor according in bulk format and import the same in OptiStruct. But make sure you know all node IDs.

Fedra853

Hi @Prakash Pagadala, thank for the reply!

I think i'll use your method!

But if i have a point, where accelleration is applied, at Xacc Yacc Zacc, this in not a node of the model. So i need first to make a linear interpolation, like the forces, or a mapping. Am i right?

How can i do that? There is a command for bulk file that allowing doing this?

Thanks

Altair Forum User

@Fedra853

You can use ACCEL1 instead of ACCEL to provide acceleration on GRID directly. See the format below:

<?xml version="1.0" encoding="UTF-8"?>

Fedra853

for recapitulate:

I create an empty Load Collector let's say with ID 33. so SID = 33
Form X1 Y1 Z1 point coordinate from my file, i create a GRID point
- in bulk file: GRID ID CP X1 Y1 Z1
- example: GRID 123 0 1.2 3.4 5.6
I take that grid point ID, A1x A1y A1z (components of acceleration) from my file and i create the accel1
- in bulk file: ACCEL1 SID CID A A1x A1y A1z ID
- example: ACCEL1 33 0 1 1E5 2E6 3E7 123
Itereate this for all 'N' acceleration that i have.

Using this method i will end up whit my accelerations associated with nodes of the model. For the analysis i will use the load collector SID 33 as LOAD input.

Am I right?

Altair Forum User

No,

SID is unique and it is like serial number for acceleration load set. So If I have 2 accel1s on two nodes, accel1 will have SID as 1 and the second will have SID 2

Fedra853

And what if i import my accelerations file like a force (in a loadcollector), using linear interpolation to associate my point to the moldel nodes. Then using TLOAD1 define the TYPE of the EXCITEID (the loadcollector previously created) as an ACCE? Is this correct?

<?xml version="1.0" encoding="UTF-8"?>

Altair Forum User

@Fedra853

You can do that but you need to convert the force to acceleration.

Fedra853

Hi, thanks for the reply!

How can i do that?

Altair Forum User

@Fedra853

This is a bit tedious task. In the txt file provide the accelration values and import the same as force data.

Now change the FORCE configuration to SPCD configuration and use the same in TLOAD1 as excited load.

Fedra853

need i to make some script that take the nodeID and the force(acceleration) value for each node and create with the same values an SPCD?

I'll put the x y z force components in dof1/2/3 of the spcd, is correct?

Altair Forum User

need i to make some script that take the nodeID and the force(acceleration) value for each node and create with the same values an SPCD?

I'll put the x y z force components in dof1/2/3 of the spcd, is correct?

Yes, you can create a script to automate the process.

Altair Forum User

Hi!

I have an external text file containing: points of application x,y,z cordinates and relative x,y,z components of an accelaration that vary for each node. Something like this:

X1 Y1 Z1 A1x A1y A1z

X2 Y2 Z2 A2x A2y A2z

....

Xn Yn Zn Anx Any Anz

I need to import this values in hypermesh for a dinamic analysis.

If they are forces i can directly import that file, and mapping the acceleration point on the nearest model node. But whit accels this in not possible.

How can i import the file and associate the acceleration at the model nodes for running the analysis in Optistruct?

Hi Fedra,

Can you please let me know how to map the force load. It will be very helpful if you can share some document.

Regards,

Kishore C