The Physics of Knives

target type

Steel

knife width (mm)

0.5

knife blade angle (degrees)

10

thickness of target (cm)

1

applied force (Newtons)

100

human arm strength has a max value of around 250 N

force needed to puncture surface =

0.84689

Newtons

parameters for a given force and target material

This Demonstration shows the force needed for a knife blade of a certain thickness and angle to puncture a surface of a given thickness and type, as well as a contour plot of what parameters a knife must have to puncture a certain target at a certain force. Included is a visual representation of the knife-surface setup. This model assumes an unbreakable blade and an ideal surface that deforms elastically before fracturing.