Abstract :
Chipping in glass plates from line-wedge
contact loading is studied as function of the wedge’s
subtended angle 2β, its inclination angle φ, and the distance
h from a corner having a subtended angle 90◦−θ.
A brittle-fracture analysis in conjunction with the FEM
technique is used to elucidate the role of geometric variables
on chip morphology and chipping load. Closedform
relations are developed for the latter by invoking
the principle of geometric similarity and taking into
consideration the details of contact forces transmitted
to the crack mouth. The fracture progresses stably until
surface effects alter the crack trajectory to form a chip.
The latter conclusively occurs from the top surface if
φ > β while from the side wall ifφ < β. The fracture
load for top-surface spalling scales with w1/2, where w
is the indentation depth, and it monotonically declines
with the offset angle ψ ≡ φ − β, that for side-wall
chipping scales with h1/2 and it is little sensitive to φ
for moderate values of θ. In both the cases, the chipping
load increases with β. The results may provide
insight into the mechanics of chipping in more complex
anthropological, tribological, geological and biomedical
applications, including flint-knapping, dentalfracture, grinding and polishing and common cutting
and machining operations
