Dynamic size effect of concrete under tension: A numerical study

• Published in: International journal of impact engineering Vol. 132; p. 103318
• Main Authors: Jin, Liu, Yu, Wenxuan, Du, Xiuli, Yang, Wangxian
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.10.2019; Elsevier BV
• Subjects: Computer simulation; Concrete; Concrete construction; Dynamic tension; Mathematical models; Mesoscale phenomena; Mortars (material); Numerical models; Particulate composites; Securities markets; Size effect; Size effects; Static and dynamic unified size effect law; Strain rate; Tensile strength; Concrete; Dynamic tension; Static and dynamic unified size effect law; Size effect; Strain rate
• ISSN: 0734-743X; 1879-3509
• DOI: 10.1016/j.ijimpeng.2019.103318

•Dynamic tensile failure of 135 double-edge notched concrete specimens are simulated at mesoscopic under dynamic loadings.•The size effect in dynamic tensile strength of concrete under different strain rates is investigated.•The proposed Static and Dynamic unified Size Effect Law in this study can well describe the size effect on the tensile strength of concrete under different strain rates. The macro nonlinearity and size effect of concrete are essentially attributed to the internal heterogeneity of concrete. Considering the heterogeneities and the strain rate effect of meso-components, the concrete was modelled as a three-phase composite composed of aggregate particles, mortar matrix and the interfacial transition zones (ITZs). Taking double-edge notched concrete specimens as examples, a meso-scale numerical model for the simulation of the failure and size effect of concrete under dynamic tensile loading with different strain rates from 10−5/s to 100/s was established. The effect of structural sizes on the dynamic tensile strength of concrete was explored. The numerical results indicate that dynamic size effect on tensile strength of concrete has an obvious discrepancy with the static one. There exists a critical strain rate (ε˙cr = 1/s), and at the strain rate the dynamic tensile strength turns to be independent on the structural size of the specimen. For the case less than the critical strain rate, the tensile strength decreases with increasing the specimen size, and the size effect on the dynamic tensile strength is weakened or suppressed as the strain rate increases. For the strain rate larger than the critical one, there is no obvious difference in the dynamic tensile strength of the concrete specimen having different structural sizes, and the corresponding size effect completely disappears. According to the influencing mechanism of strain rate effect and size effect, a Static and Dynamic unified Size Effect Law (i.e. SD-SEL) for tensile strength of concrete was built. The proposed SD-SEL was also verified by the mesoscopic numerical simulation results.