young modul prediction
young modul prediction
(OP)
hallo, does anybody has expiences with theoretical predictions of young modulus? Can you calculate (assume its value) for plastic materials by any theoretical approch?
thanks in advance
r.
thanks in advance
r.





RE: young modul prediction
RE: young modul prediction
RE: young modul prediction
Let say for very high temperatures and high loads how do you estimate than plate deflection? Which youngs module do you use? Only temperature dependence for young module is not wnough additionally one term must arive othervise you wil get unnormal deflection that is deflection above possble!
can you suggest more?
thank you
r
RE: young modul prediction
RE: young modul prediction
Testing under your real world conditions then using a pretty big fudge factor is the only safe way. That is why plastic automotive inlet manifolds have metal inserts at the bolt holes so as to take the continuous compressive load from the bolts and so prevents them coming loose and falling out.
Manifolds are typically made from heavily glass filled nylon 6.6 which has very good creep resistance for a plastic, but is still left wanting in this regard.
Simple test.
Take a test plaque, mark of an accurately measured distance along its axis
Clamp on end to a fixture with space under it.
Firmly attach a load to the other end so it stretches along the axis.
Qiuckly measure the distance between the lines.
Leave it a week, then a month and remeasure both loaded and with the load removed. That experiment tells the story.
Some raw materials manufacturers publish isocronis (isochronis?) stress strain curves, but they are probably reluctant to pass them on to the general public.
Regards
Pat
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RE: young modul prediction
It's isochronous Pat - (well it is where I live, anyway).
Here's a top Google hit... DSM info
See attached file.
www.tynevalleyplastics.co.uk
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RE: young modul prediction
RE: young modul prediction
Harry you are right. I was to slack to get out my old ICI data.
I guess they spell it the same in Gordie land as they do in Welyn Garden City, but you northerners probably say it a bit different though.
Regards
Pat
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RE: young modul prediction
http://www.engineeringtoolbox.com/young-modulus-d_...
For an understanding of how to actually calculate a theoretical value for Young's modulus for metals see FAQ330-1441: Why is the elastic modulus relatively insensitive to changes in chemistry/heat treatment/coldwork?
Maui
www.EngineeringMetallurgy.com
RE: young modul prediction
Regards
Pat
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