The development of a stabbing machine for forensic textile damage analysis

This article describes the development of a horizontal stabbing machine with an interchangeable knife holder to simulate stab events. The machine consists of a motorised arm with a pneumatic system designed to deliver 60 unique stabbing positions. The mechanics were robust and the positioning system highly reproducible with standard deviations of less than 1.0 mm in the x-axis and 2.3 mm in the y-axis for a given stab position. The force of the instrument may be varied by the operator to a maximum of approximately 221 N. The suitability of the instrument for simulating stab events was evaluated by measuring the severance length and textile damage from stab delivered from four different knives and nine penetrating angles.