Stop the dryer and make sure metal or heavy objects did not get into the load. Items such as keys and coins will make rattling and scraping sounds. Heavy objects like shoes will make a bumping sound.
If you continue to hear unusual sounds make sure the dryer is level and on a sturdy surface and then run a cycle without any items in the dryer. If the sound continues after trying these solutions please contact LG Customer Service on 0844 8475454