So, in my story, there is a fictional material called master cloth with about 10x the strength of Kevlar, and an average thread thickness of 1/8 inch diameter. The cloth is as light as most fabrics, and self-repairing of any holes that might come across it, making tailoring difficult. There will be an assassination attempt on the wealthy lord, who has managed to commission a ceremonial robe made out of this substance and which he is wearing during a city-blessing ceremony.
However, a man using a 200 to 250 lb crossbow shoots at the lord from from behind, at a range of about 40 yards. How thick would this fictional material have to be in order to let the crossbow bolt penetrate the master cloth robe and only barely scratch the skin?
This crossbow is bigger than typical and has a bolt that is also bigger than usual; the bolt is made mostly of metal, most likely a type of steel. The assassin's job is to kill the lord at any cost. The man was aiming for the base of the neck, which was not protected by the robe, but various factors contributed to the bolt's actually striking the lord down towards the small of his back.
If the crossbow can definitely puncture it, what weight or distance would it require to meet the specifications of barely puncturing but not wounding? Or multiple folds, like a wrinkle?
If this crossbow can't puncture this robe, at what draw weight or distance will it be possible to puncture, but not severely wound?