From the process, it seems like the material was process annealed. This means that it was cold worked and heat treat to a temperature above it recrystallization temperature. The purpose of annealing the Aluminum while stretching negates strain hardening.
Also, if you read a little about hot...
Hi,
Thank you desert fox and hytools.
So when the author says that the aluminum shrink plastically. That does not mean that the aluminum was deformed, does it.
If the aluminum was annealed, does that means that its yield strength was decreased to the 100Mpa yield strength that they used to...
Hu hytools
I really do not think that the composites will fall apart like hytool said. It makes sense that to relax the shrinkage pressure, one would have to raise the temperature to at least 400 C as used in creating the fit.
In designing this composite, the importance of a very low contact...
The CTE is actually 24.5*10^-6 .My mistake. The yield strength for this aluminum is between 100-170Mpa.according to the manufacturer`s the aluminum underwent deformation such that its final stress is equal to its yield strength. I used 100Mpa to be conservative.
The manufacture went on to...
Compositepro the initial contact pressure is was found based on the fact that the aluminum experienced plastic deformation during processing.During processing, it is known that the relative lengthening is three times larger that the permanent deformation at the yield strength. Therefore, the...
I understand what you are saying rb1957. So given that I can find the total deformation. I am not sure what radii to use for the OD of the graphite and ID of the aluminum, i.e, the dimension after they have been assembled. do i used the 57mm as the common interface diameter.
How do i find the...
Thank you guys. I think I know the step to arrive at the new interface pressure.
Given that I can prove that they will stay in contact. This means that the change in their radius will be equal. I can find the diametrical interference for a 166C temperature rise. Using those new diameters,I can...
Thank you Bestwrench , I have actually calculated the diametrical interference. The CTE can be assumed constant. But I am still not sure how to accomplish C and d from your advice. How do i account for the interface pressure which is trying to avoid thermal expansion. Also, if i assume no...
Thank again for your replies,
Yes, it is very interesting indeed and was accomplished. This part came from overseas actually. This is how they created the shrink fit.
The basically stretched and heated the aluminum to a point where it would shrink back to a diameter smaller than that of the...
Thank you for your prompt reply GregLocock
Yes, it experiences plastic deformation. There is actually a 0.05mm- 0.1mm gap between the aluminum and graphite before the Aluminum is heated to 400 degrees and stretched. Upon cooling, the aluminum cylinder`s inner diameter does regain it initial...
I have graphite cylinder fitted into an aluminum cylinder. The aluminum cylinder is first placed over the graphite cylinder with a 0.05-0.1mm gap, heated uniformly to 400 degrees and stretched longitudinally . Upon cooling the Aluminum cylinder shrinks plastically resulting in a 10 MPA contact...
