Fracture analysis of coating cracking on a substrate system described in a companion paper was applied and verified by four-point bending tests' The multiple cracking of coating was predicted using a fracture mechanics approach. 깐le sσain energy release rate (G) due to the formation of a new crack in a coating was obtained. A crack density vs. strain data of metallic and polymeric substrate was used to get the insitu fracture toughness of coating with respect to various baking time and temperature. The Go was decreased as the baking temperature and time was increased. This paper gave insight about usefulness of four-point bending test for fracture toughness evaluation of coating and it gave a new method for in-situ coating toughness.

Fracture analysis of coating cracking on a substrate system described in a companion paper was applied and verified by four-point bending tests' The multiple cracking of coating was predicted using a fracture mechanics approach. 깐le sσain energy release rate (G) due to the formation of a new crack in a coating was obtained. A crack density vs. strain data of metallic and polymeric substrate was used to get the insitu fracture toughness of coating with respect to various baking time and temperature. The Go was decreased as the baking temperature and time was increased. This paper gave insight about usefulness of four-point bending test for fracture toughness evaluation of coating and it gave a new method for in-situ coating toughness.