Andy,

The stiffness of any plate (ie PWB) is a function of the cube of it's thickness.
Also as a first pass will be it's strength although one must be a little careful
here as the failure crierion for a PWB will generally not be the actual fracture
of the lamininate.

So if you take the ratio of the thicknesses of the two boards and cube it, that
will equal the increase in stiffness.

Regards


Eric Christison
Mechanical Engineer
VLSI Vision Ltd
Aviation House
31 Pinkhill
Edinburgh
EH12 7BF

Tel:    +44 (0) 131 539 8165
Fax:    +44 (0) 131 539 7141

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