predicting failure after a certain time

[kateman]

Hello,

Iam trying to find a material which will fail after a week or so under roughly 2.5 giga pascals. The load will vary slightly but not overly significantly considering the magnitute of pressure. It stays between about 1 to 3 degrees celcius and stays in a non-oxidising environment. The shape of the structure is spherical. Any suggestions of material would be fantastic but thats not what iam here to ask:

Basically under the above set conditions, iam looking for some way to predict when a certain material will fail. I know this will depend on the material, how its formed, etc but those are deliberate variables which I intend to change - Iam wondering if someone could direct me to some way of being able to make an informed decision on how I could go about selecting these variables with an approximate time frame in mind of when the structure will fail.

I'd appreciate any ideas/input, thank-you!

[0xDEADBEEF]

I would go another way and make the failing not rely on the pressure. Use chemistry or melting. For most materials the break down is a run away effect. A small crack or disturbance is making it's way through the material collecting more and more pressure on the weak point and getting faster and faster, so I would guess it can go quite some time before the process starts and once it is going, it is very fast. I doubt that you will be able to hit your mark with an accuracy of a few days unless you use an active trigger, or at least a chemical process with no run away effects.

[kateman]

wow, actually you have given me something important to think about. Since then I had gone a different way but I do like what your getting at with melting. Thanks for your help, it was useful to my project =)