From: "mlbrown{at}everstrive.com" 
To: atm{at}shore.net
Reply-To: "mlbrown{at}everstrive.com" 


Original Message:
-----------------
From: Ellen Mackenzie mackenzieconsulting{at}sympatico.ca
Date: Thu, 31 Jul 2003 11:56:23 -0400
To: atm{at}shore.net
Subject: ATM re: Modulus of RTV

[snip]
    RTV Silicone does not have a very large linear portion relative to it's
stress strain range when used in thick layers [snip]

To summarize: there is no one useful value of the modulus of elasticity for
silicone; it's strain dependant.  As you load it, the stiffness changes.

However, it is easily tested; apply a load and measure the deflection. E is
the slope of the graph of stress (load/area) vs. strain
(deflection/thickness).

You can probably use the value you get under working conditions.  That is,
if you need the compression modulus (as opposed to, say, shear), make up a
sample, load it up as it would be in use and measure the distance.  Then
add some extra load and measure the distance again.  Compute the stress
(load/area of blob) and the strain (change in distance/initial distance)
and plot it up.  I'd do a 2nd point for clarity.

=Matt


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