MechEng2005 I have to agree, fatigue analysis doesnt have to be complicated if you want to just look at the endurance limit, we regularly use this method. If you have an S-n curve you can effectivly predict the life of the component based on the peak stress in the structure, although you should...
More apologies, on reflection I the strict definition of the thermal time constant has L as 1 (like 1 metre, or 1mm) which depends on wether you thermal diffsivity is given in mm or m. It varies accros the textbooks on my desk anyway...
sorry typing probably not clear
tau = (length squared)/k
where the length is any length of interest so if we are looking at a sphere and we want to know the time constant of that sphere then length would be the radius of the sphere. The time constant tells us for that sphere how long it takes...
From my undergrad physics I think there are 2 definitions and it depends on what you are trying to find out:
1) The thermal time constant tau given by
t = L^2/k where L is a length and k is thermal diffusivity tau gives the amount of time it takes for heat pentrate a body to a certain...
