FEA on PCB

[WarrenNT]

Hi All,
Does anybody know what are the appropriate material properties to use for PCB?
Our software gives the option of material type (isotropic, orthotropic, etc.), and I am sure PCB is not isotropic, but since we did not have all the data, we had to assume it as isotropic.

If somebody could advise on the reasonable assumption to use for PCB and where to find material properties (website or books?), I would appreciate it.

Thank you!

 

[rstupplebeen]

Note I have never used this material so I checked

http://en.wikipedia.org/wiki/Printed_circuit_board

chose the most comon "FR-4"
Searched matweb for FR-4 and PCB and got this link

http://www.matweb.com/search/DataSheet.aspx?MatGUID=e6e0c2f989084541b99868893e3d6ee2&ckck=1

I hope this helps.

Rob Stupplebeen

https://sites.google.com/site/robertkstupplebeen/

 

[BrianE22]

I was thininking of buying this book and was looking through the index. There's a chapter on vibration of PCBs that might offer some insight:

http://www.amazon.com/Vibration-Ana...685X/ref=sr_1_1?ie=UTF8&qid=1307035059&sr=8-1

Apart from that, you might want to check to make sure the copper traces don't add any stiffness to the board.

 

[izax1]

The material of a PCB is usually termed FR4 (GFRP), but if you are going to use this for a dynamic analysis, its more to it than the FR4 material. All the components mounted on the PCB will, to a certain extent, contribute to both stiffness and mass, and will alter the natural frequency of a PCB. Normally it would be too complicated to model all the componenets on the PCB, and therefore it would be best to do some shaker tests with a typical PCB layout, tune your model so you get the same results, and include this model into your global FE model. This is valid if dynamic FE analysis is the background for your question.

 

[jedward]

The results of any analysis will be significantly impacted by the mounting constraints imposed. PCBs slip fit into slots are significantly different from being bolted or clamped at edges.

Unless the components are physically large and massive such as transformers, modifying the bare pcb by adding mass is a reasonable approach and relatively easy to do.

Steinberg is very usefull.