脆性材料の3点曲げにおける負荷速度急変試験

抄録

In this research, the behaviour of crack-rate sensitive brittle materials in three point bending tests with an abrupt change of loading velocity was studied. The experiments using crack stabilizer and the numerical simulations taking account of crack-rate effect on fracture toughness were performed for two types of tests, i.e. incremental (or decremental) and relaxation tests. After a change of loading velocity from V₀ to V₁, a transition range on the load-deflection curve was observed. In the relaxation tests, the load decreases gradually with time. However, the stable crack extension still continued even after the loading velocity equalled zero. These results observed in incremental and relaxation tests were well simulated by the numerical simulations. It was also found that these tests were quite useful to determine the crack-rate sensitivity parameter of the test materials.