Welcome fellow Hoosier
Indiana DOES have some pretty lax knife laws regarding lengths and whatnot. However, the devil is in the details. State law prohibits automatics, gravity knives, dirks and daggers. Unfortunately, almost any knife carried on one's person can potentially be shoehorned into one of those categories by a crafty prosecutor.
I often carry a large-ish fixed blade knife on me when hiking around. Check out the HI forum, and you'll see what sizes Khukuris come in

They're handy to have. On top of that, should I NEED to defend myself with one of my knives, they would be more than up to the task.
That said, a big fixed blade isn't my self defense knife of choice. I have a couple of reasons as to why:
Firstly, I don't want to go to jail because I gut a mugger with 12" of Nepali steel. Granted, I have a clean record and am generally considered a pretty model citizen. It would be a wrong place/wrong time situation for both myself (because I wasn't keeping a situational awareness of my surroundings) and the attacker (who probably wouldn't be aware that I had a kind of knife on my belt that I have been swinging nearly daily for over a decade and am very familiar with). It looks bad to a jury.
Yeah that may be true, but isn't my life worth more than the risk? Better to be judged by 12 than carried by 6 and all that? Of course, and that brings me to my second point:
It's absolutely ridiculously easy to get a CCW gun permit in Indiana if you are not a felon. Pay your money, get fingerprinted, write a letter to the local Sheriff or Police Chief to approve, and you're done. You can carry any handgun on your person without having to take a class or pass a test...although i suggest everyone take some instruction and practice a great deal before they start carrying. That't the responsible thing to do, anyway. My point is that with minimal effort I can protect myself with a handgun much better than a knife (for the most part) and it looks better in a SD situation as I had to actually complete a very minimal amount of effort to get my permit.
That said, I DO carry a knife as a back up self defense tool. It's a folder with a 4" blade, frame lock, and a non-mechanical flipper. It's stout for what it is. I don't plan on locking blades with it, but if I can't get to my gun a 4" rapidly deployed knife may buy me the time to get away.
My main point of all this is, yes carrying most anything in our state is legal. However, USING it in a life and death situation may have more ramifications than you might think. If you can't carry a gun and decide to carry a fixed blade knife, I can totally see that as a viable way to defend yourself. I did that for many years, but it's probably not the most ideal if it can be helped.
Once again, welcome.