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Amasker

Displacement load

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Hi,I have a question,

 

In Optistruct, how to apply a displacement load on a cylindrical rigid wall to simulate a three-point bending test like following picture?

 

Thanks in advance。

 

 

三点弯.png

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Thanks,@Rahul R

 

I am so sorry I don't express it clearly,I want to apply a uniform displacement=80mm to the rigid cylinder in the Y—axis direction winthin 0.2s,like this

 

but I don't know how to make it by Optistruct?

 

 

image.png.79905d6cb6f3871f83bb5739381c5043.png

 

 

 

 

 

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Hi @Amasker

 

the B-pillar three-point bend problem would require non-linear quasistatic or dynamic analysis due to three major nonlinearities:

-large displacements/rotations/deformations

-material yielding

-contacts

 

In dynamic analysis, inertial effects and momentum are included (loading in 0.2s) while quasistatic simulates very slow movement.

 

Please go through free eBook: Introduction to Nonlinear Finite Element Analysis using OptiStruct

 

The following videos should help:

69a0f69e1b1f01cd90ed17a531e1c6979ed2aeb1.jpg?image_play_button_size=2x&image_crop_resized=960x614&image_play_button=1&image_play_button_color=005596e0

Learning Video: RADIOSS - Altair HyperWorks Insider

 

41adadc6f1d0fee92622775413b90791a0e7a377.jpg?image_play_button_size=2x&image_crop_resized=960x614&image_play_button=1&image_play_button_color=54bbffe0

OptiStruct Nonlinear Learning Center

 

Try to replicate in your model the analysis setup from the example shared by @Rahul R 

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Thank you@Ivan,

 

There is still a problem here in the example shared by @Rahul RIn Optistruct, how to set a cylinder created by myself as a rigid body and apply speed, I want to extract the contact force generated during the collision, and the rigid wall inside Optistruct cannot extract the contact force.

Or in an explicit nonlinear dynamics analysis, can RW in load steps use other geometry as a rigid wall?

 

I did a simple example,but there is no contact force in .h3d file,can you check it?thanks in advance

 

following is.fem file

 

plate_yuanzhu_SPCD_PID.fem

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In your shared deck, you have loadstep set to linear static analysis. CONTF will not work for linear cases.

Please refer OptiStruct nonlinear eBook for more information using below link.

https://altairuniversity.com/free-ebook-introduction-to-nonlinear-finite-element-analysis-using-optistruct/

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5 hours ago, Amasker said:

In Optistruct, how to set a cylinder created by myself as a rigid body and apply speed, I want to extract the contact force generated during the collision, and the rigid wall inside Optistruct cannot extract the contact force.

2

Create rigid body using 1D>rigids. Boundary conditions are applied on the master/independent node. Output requests like displacements, forces,... can be requested by Analysis>output block.

 

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It‘s very grateful,your suggestion is helpful, @Ivan ,@Rahul R


There is still a small problem here, which makes me very confused. I originally applied a forced displacement of 80mm in the direction of the dof2 y axis, but the analysis result is that the rigid body has a large displacement along the x-axis direction. I don’t understand what went wrong. here is .fem file , can you give me some suggestion?

steel_20KN_SPCD.fem 

steel_20KN_SPCD.h3d

 

And how to extract the value of specific energy absorption instead of cloud image?

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Create a rigid body on impactor cylinder and then constrain its independent/master node in all DOF and apply the SPCD on the same node. 

 

 

Attached is the edited model. Check the modifications and compare to 3pt bend example. The analysis takes a lot of iterations to converge so perhaps there is a more efficient analysis setup. 

 

ESE in the global output request will output strain energy and strain energy density.

 

steel_20kN_SPCD_edit1.hm

steel_20kN_SPCD_edit1.h3d

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