Numerical analysis of bending property of bi-modulus materials and a new method for measurement of tensile elastic modulus

In nature, there are widely distributed bi-modulus materials with different deformation characteristics under compressive and tensile stress states, such as concrete, rock and ceramics. Due to the lack of constitutive model that could reasonably consider the bi-modulus property of materials, and the lack of simple and reliable measurement methods for the tensile elastic parameters of materials, scientists and engineers always neglect the effect of the bi-modulus property of materials in engineering design and numerical simulation. To solve this problem, this study utilizes the uncoupled strain-driven constitutive model proposed by Latorre and Montáns (2020) to systematically study the distributions and magnitudes of stresses and strains of bi-modulus materials in the three-point bending test through the numerical method. Furthermore, a new method to synchronously measure the tensile and compressive elastic moduli of materials through the four-point bending test is proposed. The numerical results show that the bi-modulus property of materials has a significant effect on the stress, strain and displacement in the specimen utilized in the three-point and four-point bending tests. Meanwhile, the results from the numerical tests, in which the elastic constitutive model proposed by Latorre and Montáns (2020) is utilized, also indicate that the newly proposed measurement method has a good reliability. Although the new measurement method proposed in this study can synchronously and effectively measure the tensile and compressive elastic moduli, it cannot measure the tensile and compressive Poisson's ratios.