A Basic Study of Characteristics between Stress and Deflection on Strength Test of Bio-ceramics

摘要

Comparing the mechanical characteristics of bio-ceramics with the elaborate bone, there are two important conditions required for it. First, the strength must be three times larger than that of the elaborate bone. Second, Young's modulus must be two or three times larger than that. However, the biomaterial which satisfies these conditions hasn't developed. So, it is the main purpose of this research to clarify the relation between stress and deflection on strength test of bio-ceramics, and to get the fundamental data for improvement. In this paper, it is discussed how such quantity as deflection, stress and stress increasing rate are related. As the result, the following characteristics were found. First, deflection and the breaking stress increase as an average grain diameter of bio-ceramics becomes small. Second, the behavior of the stress increasing rate to deflection can be classified into two types. These are the fluctuation type and the stable type. Third, the experimental equations are obtained against the maximum deflection. One is for the breaking stress, and the other is for the maximum stress increasing rate. From the discussion, it was found that the characteristics of stress and deflection depended on such material properties of bio-ceramics as Young's modulus, an average grain diameter, and micro-structure of the biomaterials.