
45Defect-Induced Damage
Chapter 3
3.4.1 Stress-Field and Energy Criteria of Crack Formation
e rst study (Hopper and Uhlmann, 1970) of crack formation in the context of laser
damage considered stress generated in a glass from thermal expansion of metallic (plati-
num) inclusions embedded in the glass matrix. e only criterion for crack initiation
used in this work was exceeding the tensile strength of the material, usually estimated
as ~0.1 E, where E is the Young’s modulus. e average platinum inclusion temperature
required to generate such stress was estimated at ~1 × 10
4
K. is result was obtained
using a simplied model of a sphere of a size ...