This document summarizes a study on the force required to penetrate skin with broken glass bottles. The study tested different bottle types by smashing them against a steel table and measuring the force needed to push the broken glass into a skin simulant. The results showed that the force varied depending on how the bottle fractured, with three main fracture patterns observed. On average, more force was required for broken bottles to penetrate than knives, due to the unique "stabbing surface" geometry created when bottles break. The study aimed to provide quantitative data on bottle injuries to aid legal professionals.

1. ‘Glassings’ and Stabbings – Bottles as Weapons
The Engineering Story
Gary Nolan ∙ Professor Guy Rutty ∙ East Midlands Forensic Pathology Unit and Department of Engineering
CONTEXT Results
• Injuries and assaults related to alcohol •Penetration force varies depending on fracture
consumption are a growing concern in many •Glass fractures from weak areas – statistical
countries variation in where fracture initiates
• Use of impulsive weapons such as a glass bottle •No clear correlation with bottle type
is not uncommon
• Bottles and glasses are used in approximately
10% of all assaults resulting in treatment in the UK
• 3,400 and 5,400 offences per year
What is the force required for
a broken glass bottle to
penetrate a skin simulant?
How does this
compare to
Can we estimate forces knives? The average force required for penetration of the skin
simulant for each bottle
from knowledge of how
bottles fracture? Bayonet
Can we categorize the
geometry of bottle
failures to aid
How do we present practitioners?
the information Extended Shards
to juries?
TESTING
• Wall thickness of bottles measured using multi-
detector computed tomography (MDCT)
Tulip
• Bottles smashed against a steel table
• MDCT protocol repeated on smashed bottles
• Force and displacement to push bottles into skin
simulant measured using a Materials Testing
System (MTS)
• Peak force to penetrate skin simulant recorded
Conclusions
•When a bottle is used as a weapon the neck of the
bottle is used as a handle
•Three categories of fracture patterns (see above)
•Multiple points of contact at the edge of the broken
bottle produces a surface with a combination of blunt
and sharp points
•Smashed bottles have a unique ‘stabbing surface’,
meaning it is not possible to predict a definitive value
of force involved in an assault
•Due to the geometry of the ‘stabbing surface’ of
bottles most require a greater amount of force to
penetrate than knives