Which part I have to broke an Iphone to get new one?

If warranty have on the iPhone they're gonna give you new iPhone if something wrong with your iPhone right? My question is which part i have to broke to get new one and when Apple checks it shouldn't show it broken by myself, I knew its not good but just answer me

I accidently broke the screen on my iphone 3g, they sent me a 3gs under warranty (yes that was about 4yr ago lol)

You never get a brand new one, it would be a refurbished one. Refurbished is still good though. Odds are anything you do fraudulently like that will end up costing you money.