title: An Impact Velocity Device Design for Blood Spatter Pattern Generation with Considerations for High-Speed Video Analysis.
abstract: A mechanical device that uses gravitational and spring compression forces to create spatter patterns of known impact velocities is presented and discussed. The custom-made device uses either two or four springs (k1 = 267.8 N/m, k2 = 535.5 N/m) in parallel to create seventeen reproducible impact velocities between 2.1 and 4.0 m/s. The impactor is held at several known spring extensions using an electromagnet. Trigger inputs to the high-speed video camera allow the user to control the magnet's release while capturing video footage simultaneously. A polycarbonate base is used to allow for simultaneous monitoring of the side and bottom views of the impact event. Twenty-four patterns were created across the impact velocity range and analyzed using HemoSpat. Area of origin estimations fell within an acceptable range (ΔXav = -5.5 ± 1.9 cm, ΔYav = -2.6 ± 2.8 cm, ΔZav = +5.5 ± 3.8 cm), supporting distribution analysis for the use in research or bloodstain pattern training. This work provides a framework for those interested in developing a robust impact device.
authors.affiliation: Materials Science Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, Canada, K9J 7B8.
authors.forename: Theresa
authors.initials: T
authors.lastname: Stotesbury
authors.affiliation: Materials Science Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, Canada, K9J 7B8.|Forensic Science Department, Trent University, 1600 West Bank Drive, Peterborough, ON, Canada, K9J 7B8.
authors.forename: Mike
authors.initials: M
authors.lastname: Illes
authors.affiliation: Materials Science Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, Canada, K9J 7B8.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Vreugdenhil
mesh_terms: D001801:Blood Stains; D004867:Equipment Design; D005554:Forensic Medicine / Q000295:instrumentation*; D006801:Humans; D012984:Software; D014741:Video Recording
keywords: area of origin; bloodstain pattern analysis; forensic science; high-speed video; impact device; impact patterns; impact velocity; spatter generation