Calculation Method of Equivalent Indenting Young's modulus E_(rr)(h_r) with Tangent depth method in case of Poisson's ratio v_s unknown in I. I. T.

摘要

It has been reported that Tangent depth method in Instrumented Indentation Test: I. I. T. is more useful to calculate Equivalent Indenting Young's modulus E_(rr)(h_r) for many kinds of materials. [1], [2], [3] But to calculate E_(rr)(h_r) with Tangent depth method proposed, Poisson's ratio v_s must be assumed. If Poisson's ratio v_s is unknown, then value of v_s will be practically assumed 0. 3. Especially for metals, v_s = 0.3 is an appropriate value. Regrettably, v_s =0. 3 cannot apply for having low Young's modulus materials as Glasses or for having high Young's modulus materials as Sapphire, Tungsten Carbide, Diamond and so on. Therefore, to establish the universal way of calculating E_(rr)(h_r) with Tangent depth method for many kinds of materials, the calculation method of E_(rr)(h_r) with Tangent depth method in case of Poisson's ratio v_s unknown must be needed. In this Review, two ways of the calculation method of E_(rr)(h_r) with Tangent depth method in case of Poisson's ratio v_s unknown are shown. As a result, the universality of Tangent depth method has been established.