GAO Tengteng, MA Dejun, SUN Liang, WANG Lizhi
(Academy of Armored Force Engineering, Fengtai 100072, Beijing, China)

Abstract: In this paper, finite element analysis was used to study the effect of different tilt angle of materials’ surface on two representative instrumented indentation methods: Oliver-Pharr method and Ma method. The results of the finite element analysis show that the values of elastic modulus derived by Oliver-Pharr method and Ma method increase with the tilt angle. While the tilt angle was minor (less than 3°), the errors of both methods are less than 5%, which means that the minor tilt angle of ceramic samples has a small effect on the test; while the tilt angle is 4°, the maximum errors of Oliver-Pharr method and Ma method are 6.88% and 6.79% respectively, which means that the result was evidently affected if the tilt angle is above 4°. So the smoothness of the ceramic sample must be focused in order to improve the test precision during the sample preparation course.

Key words: instrumented indentation; ceramic; elastic modulus; slope; finite element analysis