Also: Mario Di Giovanni, Flat and Corrugated Diaphragm Design Handbook. (Marcel Dekker, New York, NY, 1982). Was out of print, but they seem to have done another printing. In any event, available in some university libraries, and from Amazon. Discusses not just circular geometries, but squares and rectangles, too. --- Albert K. Henning, PhD Director of MEMS Technology NanoInk, Inc. 215 E. Hacienda Avenue Campbell, CA 95008 408-379-9069 ext 101 ahenning@nanoink.net -----Original Message----- From: igor tchertkov [mailto:itchertkov@yahoo.com] Sent: Tuesday, October 27, 2009 9:09 AM To: General MEMS discussion Subject: Re: [mems-talk] Displacement function for cirque diaphragmunder pressure http://www.roarksformulas.com/ igor