A bent chassis is usually an indicator one of two possibilities...
1) The iPad has been in a backpack/bag with other items. Pressure has physically distorted the chassis, and in some cases leading failure of the adhesive that holds the screen to the chassis.
2) The battery is swelling due to an internal battery-fault.
In either case, your iPad needs to be inspected and assessed by an Apple Technician at the Genius Bar of your local Apple Store. Alternatively, the same examination can be carried-out by an Apple Authorised Service Provider.
For practical purposes, in lieu of repairing and returning your own iPad, Apple usually exchange the iPad for a renewed/refurbished iPad of the same model and specification. The cost of the exchange is the same as would otherwise be charged for repair. Unless you have benefit of an active AppleCare plan, an out-of-warranty repair while expensive will be somewhat less than the cost of a replacement iPad.
As for out-of-warranty repair costs, Apple offers a fixed-price price repair. You can verify eligibility and cost for your region/country here:
iPad Repair & Service - Apple Support
If you have an active AppleCare+ plan, the cost of repair is reduced to a small excess/deductible fee.