Bragg Grating defined: http://www-personal.umich.edu/~bkerkez/courses/cee575/Handouts/7FBGS_StrainMeasurement_mo.pdf


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From: TechNet <[log in to unmask]> On Behalf Of Yuan-chia Joyce Koo
Sent: Tuesday, October 6, 2020 12:36 PM
To: [log in to unmask]
Subject: Re: [TN] Bending a Board Assembly

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if my memory serve me right, there are few papers on the topic using fiber bragg grating to study either thermal or mechanical stress.  I believe Celestica is one of the company might have done it in the past.  Not sure what is published data (might be IEEE if not SMTA).
fyi only.
jk
On Oct 6, 2020, at 11:12 AM, Jack Olson wrote:

> We are considering a change to a manufacturing process which will save 
> time and money, but will cause extra stress on the completed board 
> assembly.
> Q1) I'm familiar with bow and twist for bare boards, but is there data 
> on flexing a completed assembly? I'm sure it depends on board 
> thickness and material, etc. but is there danger to the  board itself? 
> or does it always break a component first?
> Q2) I'm NOT familiar with stress on components. How can I determine 
> whether we are in danger of damaging components, especially SMDs?