R-Pod 178 axle

"Yield strength is the maximum stress that can be applied before it begins to change shape permanently. This is an approximation of the elastic limit of the steel. If stress is added to the metal but does not reach the yield point, it will return to its original shape after the stress is removed. When the stresses exceed the yield point, the steel will not be able to bounce back. Yield strength represents the upper limit of the load that can be safely applied to the metal, which makes it a very important number to know when designing components."

So, when an axle becomes decambered it is because it was subjected to one or more events where it received stresses in excess of the yield strength and did not return to its original shape. In that sense it is "bent".

I did the calculations for rPod axle loads and found that the steel axle tube reaches the yield point at a load a bit less than 2x the 3500 lb rated axle load. That might sound like it should be fine but its not, because many rPods like mine and toyanvil's are running near their max axle loads, and because moving vehicles are subject to bump loads that can frequently be higher than 2 g's. No one in the trailer or vehicle manufacturing industry will say what their frames and axles are actually designed to, but general guidance is to be at least 2.5 to 3 g.  So rPods are less than that, they are very lightly built.

As toyanvil says, just because an axle is decambered doesn't mean it can't be bent back to its original shape, and I agree this is a better approach than simply getting a new axle of the same rating, assuming that the axle tube has not been severely damaged. A good trailer frame shop can tell you. 

Then, unless you keep the rPod light and stay off of rough or potholed roads, reinforce it using one of the methods you can find doing a search on this forum. As toyanvil points out, it is the inboard mounting points that cause the axle to experience much higher loadings than would be the case if the axle to frame mountings were out nearer the wheels as they are in most other trailers. 

This all applies to a decambering axle failure. There are other ways an rPod axle can be damaged besides being decambered, although that seems to be the most typical thing that happens in rPods. 

So, back to the original question, what has actually occurred that makes you say your axle is "bent"?