Evaluation of Poisson’s ratio for thin soft material by multiplex procedure of spherical indentation mechanics

The Poisson’s ratio plays a significant role in material science and manufacturing, and it should be effectively identified for thin soft materials. In this study, a theoretical multiplex procedure is proposed with spherical indentation to identify the Poisson’s ratio of thin soft materials. First, the spherical indentation theories of full contact, fundamental and extended Hertzian are functional separated. By analyzing the sensitivity of the separated terms in each theory, the multiplex procedure is developed. Then, computational simulations are performed to observe the indentation behavior of same thin soft material tested by each theory. The numerical results are approximately fitted by each theory under initial and large indentation depth. Both extended Hertzian and full contact theories show high feasibility to fit the numerical results, while the fundamental theory is applied in the initial contact region. Subsequently, the multiplex procedure is conducted to identify the Poisson’s ratio by the full contact theory with fundamental and extended Hertzian theories. The result indicates that the multiplex theory developed herein is depending on the contact theories and indentation depth. Consequently, by using the multiplex theory, the accurate identification of Poisson’s ratio for thin soft materials can be realized in the case of large Poisson’s ratio, extended Hertzian theory and initial indentation depth.