Quartz Circular Plate

[cdi12]

Our mechanical engineer is asking me to check circular plate made of quartz. Plate is about 14” dia and 2” thick with a lot (about 150) holes 3/16” dia. All quartz properties (E, yield, allowable tensile stress, …) were given. I am considering modeling this plate with triangular plate elements. Any advice how to analyze this plate would be appreciated.

 

[JStephen]

I'd probably use the circular plate formulas from Roark's Formulas for Stress and Strain, and then multiply by appropriate stress concentration factor for circular holes.

I would think if you really wanted to get more detailed than that, you'd probably be looking at a solid model rather than plate elements. That could get involved modeling around the holes, especially if they have any chamfer at the edges. Somebody that did this all the time could probably whip it up pretty fast, though.

 

[mudflaps]

Sounds flaky to me. I recommend testing a prototype to failure then taking a reduction. As I remember Quartz is a crystalline material so you'll have to adjust for that too.


Old CA SE

 

[kslee1000]

Just curious, does quartz possess linear elastic behavior, and considered as a homgeneous, isotropic material?

 

[btrueblood]

"Just curious, does quartz possess linear elastic behavior, and considered as a homgeneous, isotropic material? "

Yes, and yes. But, it is also a brittle material, (so any "yield strength" he was given is nonsense). Also has problems with crack propagation, variable strength due to flaws/inclusions, and is susceptible to SCC in certain fluids. All of which typically call for a rather large knock-down for allowable strength.

 

[kslee1000]

btrueblonod:

Thanks. My questions were meant to validate cdi12's data which sounded odd to me.

cdi12:

The following is my personal opinion - you shall double check the properties with a knowledgable material engineer competent in this field, and discuss with him the behavior of quartz under the proposed application before spend time and energy to build a monstrous medel without clear criteria and realistic expectation of outcomes.

 

[kslee1000]

Sorry for not doing homework before posting my reply. Checked on the web, and realized its composition and properties are comparable to the glass (a brittle material with very low tensile strength). what is your application?