Fracture Evaluation of Low-Density Porous Materials by Reaction Force Analysis in Ball Indentation Test

Abstract

An indentation test can easily measure the deformation characteristics of a material, because it does not require a test specimen to be cut from the material being examined. The applicability of this test is usually restricted to evaluating the fundamental characteristics of deformation, such as elasticity and plasticity; however, it is also useful if the test can be applied for the fracture evaluation of materials. Therefore, in this study, the fracture behavior of materials is discussed by performing indentation tests. The evaluation procedure depends on the variation in the indentation force owing to the differences in the deformation behavior. The observed variation is analyzed via the fractography of the material. A simple formulation is derived from the results for the development of a material evaluation method. Finally, the importance of the choice of the indenter diameter is explained in terms of the accuracy of the plateau stress of the porous material.