If I destroy such evidence and I sue to recover for my personal injuries, what penalties can be imposed?

Depending on many factors, if a court finds that a plaintiff or a defendant has spoliated evidence, it may impose minor or in some cases very serious sanctions including dismissal of the case or in the case of a defendant, striking of an answer and imposing a finding of legal liability against the offending party. In short, never spoliate evidence. Period. Get it to your lawyer and make sure that it is properly maintained.