Is it permissible for a female student to take extra money from her father, beyond her university expenses, without his knowledge, especially if her father does not give her money for her personal expenses, and their financial situation is good?

It is not permissible for a sister to take from her father's money except with his permission, unless he is not providing her maintenance and she is in need and he is able to provide. In such a case, she may take what suffices her and her children in a reasonable manner, as in the hadith of Hind bint Utbah. She must avoid lying and using dissimulation.