I have read some papers about fracture mechanics of functionally graded materials. I find there are different results for the stress intensity factors when the crack length is close to "0" . In some papers the values of stress intensity factors are "1" when the crack length is close to "0" , but in other papers the values of stress intensity factors are not "1". I obtain the stress intensity factors is "1" when the length of crack is close to "0". I hope to get the explaination about the results.Thanks a lot.