Modelling edge chipping in flint knapping, cutting tools and sharp teeth using a trapezoidal prism structure

Edge chipping tests were performed on trapezoidal prisms made of soda-lime glass and two rock materials, and the evolution of damage observed in-situ. The indent distance H and specimen's wedge and surface inclination angles α and θ were systematically varied. The configuration used, distinguished by two free surfaces interacting with the chipping crack, yielded the type of chip morphology commonly found in such applications as flint knapping, material shaping tools and some dental teeth. The tests were complemented by a fracture mechanics analysis incorporating all system variables as well as load orientation angle ϕ. The analysis produced closed-form analytical expressions that predicted reasonably well the chip dimensions and chipping force. The results presented provide useful insight into such aspects as the mechanics behind rock shaping, fracture prevention in material shaping tools and bite force of some mammals and sharp-teeth fish based on inspection of chipped fossil teeth.