Frequency response analysis

Altair Forum User

I am supposed to do vibration analysis on the following components. I haven't done this kind of analysis before. I appreciate if you can give me a step by step process for doing this in optistruct

The objective is to Determine during vibration, whether there will be contact anywhere between the lightguide and lens during any vibration loading scenario given below. 

 

- Note, in order to do this analysis, assume vibration is transmitted via the base fixture (to be supplied along with the part data), and then the part will respond to this vibration accordingly. 

- Profile shown below, to be repeated 3 times, one for each axis (X, Y, and Z):

1. Frequency = 20 Hz, PSD = 9.9248 (m/s^2)^2/Hz (passenger/ trunk sprung masses)

2. Frequency = 60 Hz, PSD = 3.2313 (m/s^2)^2/Hz (passenger/ trunk sprung masses)

3. Frequency = 120Hz, PSD = 0.1250 (m/s^2)^2/Hz (passenger/ trunk sprung masses)

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Rahul Rajan_21763

Hi,

Refer optistruct online tutorials for Random response analysis & below post for similar model with base excitation.

 

 

 

Regards

Rahul R

Altair Forum User

Hi

Thank you for your reply. Actually the tutorials do not match my problem. In my problem the only known parameters are frequency and PSD

Would you please guide me what to define for parameters J, k, X and Y?? (The load Collectors that I have defined are as follows: 1. SPC (constraints) 2. TABRND1 (to define frequencies and PSD). 3. RANDPS (for random response analysis)

Do I have to define any other load collector??

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I appreciate your help

Altair Forum User

Hi,

 

J, K refers to the loadcases which has the loads (applied/excited). J and K can refer to the same loadcase in which case Y will be zero.

 

Please refer to RANDPS card in OptiSrtuct help for more information.