BASE INPUT ON FRF or RANDOM or TRANSIENT ANALYSIS

Hi to everyone,

  how it is possible to assign a shift or an acceleration to the base of the structure for a FRF analysis? In particular, if i use SPCD on constrained DOF (SPC), i ve rigid body motion on SPCD dof. 

as example: 

 

NODE 1: FIX CONSTRAINTS on 6 DOFs (SPC)

NODE 1: ACCELERATION on DOF 1 (SPCD)

 

I ve a rigid body motion on dof 1.

 

I want a structure fix on constraints but with an applied acce on one or more dofs (that are constrined)... like a Rensponse Spectrum Analysis.

 

thank you to all..

 

 

 

 

 

 

Hi 

Can you share any image regarding it?

My case is like this:

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

I ve RIGID BODY MOTION on x direction

Hi,

Here is a file where 6 Dofs of a node are constrained and SPCD is applied on the same node,

Unable to find an attachment - read this blog

My case is like this:

 

 

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

 

I ve RIGID BODY MOTION on x direction

What response are you expecting?

ok @Prakash Pagadala, i ve read this also on optistruct manual. How can I solve my problem?

@Jebunderscore

Not sure what is happening with your model.

If it is allowed, please share the model using the file transfer link

my model is like your attached model. I want only the acce on constrained node, like a response spectrum. i ve solved my problem, i ve constrained the model on a portion near the applied acce. But there is a possibility to set an analysis (FRF ecc) with acce applied on the same constrained nodes?

thank you .

my model is like your attached model. I want only the acce on constrained node, like a response spectrum. i ve solved my problem, i ve constrained the model on a portion near the applied acce. But there is a possibility to set an analysis (FRF ecc) with acce applied on the same constrained nodes?

thank you .

Hi J

I think what you did is, you gave spcd to all the nodes which had SPC because of which whole body will tend to move in that particular direction without opposition. You need to leave some nodes to oppose the SPCD motion. Release some node from SPCD and i think you can get answer to what you are looking for.