Is there any evidence she was raped in prison? I was under the impression her attackers were never successful.
Men's clothing was certainly less accessible than a woman's skirts in this period. She was not asking to wear armour in prison but dressed in male garments which someone obviously supplied her with. She was not raped but certainly had good reason to fear it. Aimon, Lord of Macy's deposition at the Nullification Trial is quite explicit:
Asked about the contents of the 1st, 2nd, 3rd and 4th articles produced in this case, he said and declared upon oath that he first met Joan when he saw her detained in the prison cells in the castle of Beaurevoir, for and in the name of the Count of Ligny; he saw her any times in prison and spoke with her often. Many times too, in sport, he tried to touch her breasts, trying hard to put his hands on her bosom; but Joan was not prepared to put up with this, and pushed away the witness as hard as she could, because this Joan was of honest behaviour in words and deeds.