How to animate a illustrator blend in after effects?

If you want actually animate a blend in Illustrator, try this:

Here's an earlier version of the same idea. I've been doing this kind of Illustrator to Video animations since you could import an AI file as a composition. 

But as Mylenium said, if you just want a moving light rays effect, the easiest and most powerful solution is Trapcode Shine or any of the other effects he mentioned. You just need to start with a logo without the light ray blend and the appropriate effect.

You would simply use the black outline and slap on one of the five million light ray effects out there, including CC Lightburst which comes with AE, Trapcode Shine, Sapphire Rays and what have you. More to the point you'd apply the effect to an inverted white version of the logo and then play with the parameters.

Mylenium