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Sorry here are the correct linkshttp://files.engineering.com/getfile.aspx?folder=bfa4cb95-1580-498c-a44c-ebb93a4a4e05&file=modalfreqrestartnoresvec.zip http://files.engineering.com/getfile.aspx?folder=afd311a1-46d5-45e8-bf8b-bb8a688b0654&file=modal.zip...

Dear Joe, I did some other tries but I'm not sure of what happened, restart still seems to be useless to me.. I'm attaching the following files: -.dat (without nodes and elements), .f04, .f06, .log of first modal analysis with database saving for restart (modal.zip) -.dat (without nodes and...

Dear Joe, thanks for the reply. I also tried running a frequency response analysis with restart after a modal analysis disabling the RESVEC, but nothing changed in the running time... Always stting up everything from inside FEMAP 11.1.0. Marco

Hello Joe, thanks for the reply. I'm not using the example problems but a model with about 100000 nodes and 800 modes in the first 2000 Hz, that's why I would like to use restart to avoid repeating the modal analysis every time I perform a random / frequency response run, it's very time...

Hello, I'm using FEMAP 11.1 with NX Nastran for frequency response and random response analyses. Following tutorials I'm using the restart capability performing first a modal analysis then the frequency response (modal frequency method) using the saved database from the modal analysis. The...

Hello, I'm performing a random response analysis with FEMAP 11.1 and NX Nastran on a model with a very high number of modes (about 850 from 0 to 2000 Hz). The PSD spectrum is in 20-2000 Hz range. The modal frequency method gives me a result with a modal critical damping of .03, although I had to...

Dear Blas, thanks for the answer. I already read your tutorial, and I just have to perform a shock response spectrum analysis on an electronics box. I have my SRS input curve (acc vs frequency) from customer, to be applied to a base node connected to the box constraint points. My question is...

thread825-258197 Hello, I'm performing a SRS analysis with FEMAP 11.1 and NXN 9.0. I'm following the FEMAP tutorial no.19 doing a modal analysis applying a SRS (acceleration vs. frequency)on a node with a large mass and a SUPORT entry in the excited DOF. My question is: is it mandatory to use a...

Dear NX.Nastran/FEMAP users, I have to perform a SRS analysis, applying a SRS load as follows to an assembly model: 500 Hz -> 500 g 3000 Hz -> 2000 g 10000 Hz -> 2000 g I have never done that: how do I apply this load to my model? Is there any tutorial or example available? Thanks Marco

Dear Nastran/FEMAP users, I have to perform a SRS analysis, applying a SRS load as follows to an assembly model: 500 Hz -> 500 g 3000 Hz -> 2000 g 10000 Hz -> 2000 g I have never done that: how do I apply this load to my model? Is there any tutorial or example available? Thanks Marco

Hello everyone. I'm working on this problem: I have to verify the good choice of a filtering/venting PTFE membrane with a porosity 0.2 micrometers. It's applied on a closed box that undergoes a thermal vacuum test inside a vacuum chamber, with a pressure change rate of 200 mbar/min, and it is...

Hello, I don't use NX but Nastran with Femap as pre-post, with the licence for dynamic analysis. I am able to perform freq response and to apply PSD, but I would like to know how to consider the results, since I can have PSD of component stresses, and not Von Mises. Is there any standard procedure?

Hello, I have a requirement for a max leak rate with He in a pressure vessel (1e-4 mbar*l/s). I want to test it with pressure decay method, but using Nitrogen instead of He. What is the correct calculation of leak rate using Nitrogen, and the translation in max pressure decay (mbar/s)? The...

Hello everyone, could anyone plase tell me what is the correct procedure to perform a structural analysis by FEA on an item subjucted to random vibration? I work in aerospace field and use NX.Nastran with Femap. I know the input PSD for this item and I would like to verify its strength. It...

Yes, continuous fillet weld.

Hello, in my company we have designed and manufactured a stainless steel vacuum chamber needed to perform a vibration test of an item under vacuum conditions. When performing random vibrations at full level, after some time, the weld on the chamber base broke on 180° circumference. What can I...

Thanks for your replies. Does anyone know if there is a standard to use as reference when performing a passivation (cleaning) of titanium ti6al4v? Marco

Thanks unclesyd, I found Tiodize. The problem is I'm in Italy and the suppliers I contacted don't use the AMS 2488 / Tiodize anodization procedure, so I would like to know if there is any alternative. Marco

Hello, I have to manufacture a part in Ti6Al4V due to stiffness reasons, for a space application. Our customer told us that, due to poor resistance of this material to fretting and wear, we'd better apply a surface treatment. The suggested alternatives are anodic oxidation as per SAE AMS 2488D...

Hello, I have to perform a verification of a glued connection between titanium and bronze parts. The available glue data are tensile, shear (wrt temperature), compressive and flexural strength. I have a bronze bellows with 8 bar pressure inside glued on a titanium structure, then I have to...