Meso-scale modelling of the size effect on dynamic compressive failure of concrete under different strain rates

• Published in: International journal of impact engineering Vol. 125; pp. 1 - 12
• Main Authors: JIN, Liu, YU, Wenxuan, DU, Xiuli, ZHANG, Shuai, LI, Dong
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.03.2019; Elsevier BV
• Subjects: Compressive properties; Compressive strength; Computer simulation; Concrete; Dynamic compressive; Failure; Mesoscale phenomena; Securities markets; Size effect; Size effects; Static dynamic unified size effect law; Strain rate; Temperature; Concrete; Static dynamic unified size effect law; Dynamic compressive; Size effect; Strain rate
• ISSN: 0734-743X; 1879-3509
• DOI: 10.1016/j.ijimpeng.2018.10.011

•Dynamic compressive failures of 150 squared concrete specimens are simulated at meso-scale under dynamic loadings. (The applied strain rates are: 10–5/s, 10–3/s, 10–2/s, 10–1/s, 1/s, 10/s, 30/s, 50/s, 100/s and 200/s. The widths of the specimens are: b = 100, 150, 300, 450 and 600 mm.)•The size effect in dynamic compressive strength of concrete under different strain rates is investigated.•The contribution of strain rate in dynamic compressive size effect can be divided into two parts: the strength enhancement, and the weakening and reverse enhancement of size effect.•The proposed Static and Dynamic unified Size Effect Law (SD-SEL) in this study can reflect the relation between dynamic size effect and static size effect, and it can well describe the size effect on the compressive strength of concrete under different strain rates of 10–5∼200/s. Great progresses have been made in static size effect of concrete, while almost no efforts have been conducted in dynamic size effect of concrete. The macro nonlinearity and size effect of concrete should be attributed to the inner heterogeneities. Herein, a meso-scale simulation method was built to study the dynamic failure and size effect of concrete. In the approach, the concrete heterogeneities were explicitly described, and the strain rate effect for the meso components were also taken into account. Taking squared concrete specimens as examples, the dynamic compressive failure and the size effect of concrete under different strain rates from 10−5/s to 200/s were modelled and investigated. The effect of strain rate on the size effect in compressive strength of concrete was also explored. The simulation results indicate that, there exists a critical strain rate (ɛ˙cr=1/s). When the applied strain rate is less than the critical strain rate, the compressive strength decreases with increasing the specimen size and the size effect on the dynamic compressive strength is weakened as the strain rate increases. The dynamic compressive strength turns to be independent on the structural size of the specimen for the critical strain rate. When the applied strain rate is more than the critical strain rate, the compressive strength increases with the increase of specimen size and the size effect on the dynamic compressive strength is enhanced as the strain rate increases. Finally, based on the influencing mechanism of strain rate effect to dynamic strength and size effect, a Static and Dynamic unified Size Effect Law (i.e. SD-SEL) for compressive strength of concrete was established. The proposed size effect law was also calibrated by the meso-scale simulation results.