May be I am wrong, but the SD card will only be corrupt if you shut your pi down in the middle of a write operation.
So, most of the time nothing will happen when you abruptly shut it down.
If you want to make sure that it will not break, use an operating system which does not write to the SD-card. Those systems are often called 'live'-cd. Thry often have the option to mount a usb drive as wtitable medium in oder to store some changable data.
But even when you shut down your pi during a wtite process, the damage depends on the filesystem and on which data it was about to write. Most of the time, only this data file will be corrupted.
Uodate: look for journaling file systems. Afaik reiser fs is one. These file systems are build to recognize corrupt files and restore them. So if you manage to use such a fs, you should be nearly on the safe side, even when your app writes a lot of data. Nearly, because even those file systems cann bring your files in an inconsistent state. For instance when your app tries to make a change in two files but only one of them is corrupted.