title: Determination of Fracture Patterns in Glass and Glassy Polymers.
abstract: The study of fractures of glass, glassy-type materials, and plastic has long been of interest to the forensic community. The focus of this interest has been the use of glass and polymer fractures to associate items of evidence under the assumption that each fracture is different. Generally, it is well-accepted that deviations exist; however, the emphasis has been on classifying and predicting fracture rather than determining that each fracture is different. This study documented the controlled fracture patterns of 60 glass panes, 60 glass bottles, and 60 plastic tail light lens covers using both dynamic impact and static pressure methods under closely controlled conditions. Each pattern was intercompared, and based on the limited specimens tested in this study, the results illustrate that the fracture patterns are different. Further repetitive studies, under controlled conditions, will be needed to provide more statistical significance to the theory that each fracture forms a nonreproducible fracture pattern.
authors.affiliation: California Department of Justice, Riverside Criminalistics Laboratory, 7425 Mission Blvd., Riverside, CA, 92509.
authors.forename: Allison C
authors.initials: AC
authors.lastname: Baca
authors.affiliation: UC Davis Forensic Science Graduate Program, 1909 Galileo Ct, Suite B, Davis, CA, 95628.
authors.forename: John I
authors.initials: JI
authors.lastname: Thornton
authors.affiliation: UC Davis Forensic Science Graduate Program, 1909 Galileo Ct, Suite B, Davis, CA, 95628.
authors.forename: Frederic A
authors.initials: FA
authors.lastname: Tulleners
keywords: forensic science; fractography; fracture patterns; glass fracture; physical match