Google search shuts down whenever I try to use it

You can try the following to resolve this issue: 

1. Force reboot your device by holding down the Power button and Home button until the device flashes the Apple logo. This works so well for resolving many common app crashing issues, and it’s so simple, that you absolutely should try this first. 
2. Quit the app then relaunch it 
3. Update the App 
4. Delete the App then re-install it 
5. Update your iOS to the latest version 

Hope it helps! 

Glad it worked! :D