Breton - The question when a failure occurs due to creep is not time based but strain based. Naturally both are coupled with the deformation rate. This is the basic idea of the Coffin-Manson relationship. - Wow wow, this question is really a trap. I wouldn't dare to name such an assumption. To stick with Coffin- Manson, each %GBS / %DC would in fact ask for a damage exponent. Now, since DC leads to a faster degradation than GBS There might be a line after which GBS becomes negligible. However, as you see from the diagrams I mailed you, it is not easy to activate pure DC. Thus it is quite a task to work out the damage exponent for pure DC. At my present status of know how there is no way to define such a border. As a matter of fact we where working on this item when the "big bang", leadfree solder, came. Now I am forced to start a project to do the whole job again. Best regards Guenter ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################