Modeling of progressive damage in concrete using multidimensional virtual internal bond method

Abstract

Summary Damage simulation via tensile and shear failure modes in quasi‐brittle material like concrete is computationally challenging. Multidimensional virtual internal bond (MVIB) method is one of the promising method developed to capture shear failure in materials like concrete. It assumes continuum as an assemblage of material points joined by normal and shear bonds possessing harmonic potential and bond density evolution function, which degrades with deformation to yield at macroscopic level, stress–strain law with inbuilt feature of failure via Cauchy–Born rule. The degradation of bond‐density in MVIB method originally based solely on compressive failure is extended to include tensile failure synonymous with tension and compression asymmetry in concrete. The modified MVIB model is applied to a variety of problems, and the effect of inclusion of both tensile and compressive failure is thoroughly assessed. Through the example of two notches in a square plate subjected to biaxial loading, a systematic study of damage evolution vis‐à‐vis biaxial loading ratio is presented. Capture of crack closure and formation of crack retarding protective shield are unique outcomes of the present work.

Independent cover isogeometric Reissner‐Mindlin shell model for the simulation of the fabricated lining

“…By virtue of the strong adaptability to surrounding rock, little impact on environment, mechanized operation, high construction speed and low labor intensity, the fabricated lining is widely used in the underground rail transit, the water conveyance system and the river‐crossing tunnel, for instance, the circular subway tunnel in Figure 1 and the rectangular underground passage in Figure 2 1–5 . With the rapid development of the urban infrastructure construction, the burial depth, diameter and load of the fabricated lining all present an increasing trend, which brings enormous challenges to the design 6–8 . For example, a shield tunnel for the conveyance and regulation of rainwater below the Suzhou River in Shanghai, China is buried over 40 m. A single‐layer lining with an inner diameter of 10 m is employed for this tunnel and an ultra‐high internal water pressure of 0.6 MPa needs to be borne, which is the largest internal pressure among those of the similar tunnels in China.…”