A numerical estimate method of dynamic fracture initiation toughness of rock under high temperature. (December 2018)

• Record Type: Journal Article
• Authors: Yin, Tubing; Zhang, Shuaishuai; Li, Xibing; Bai, Lv
• Is Part Of: Engineering fracture mechanics. Volume 204(2018)
• Page Start: 87
• Page End: 102
• Publication Date: 2018-12
• Subjects: Dynamic fracture toughness -- High temperature -- DEM -- SHPB -- Granite; Fracture mechanics -- Periodicals; Rupture, Mécanique de la -- Périodiques; Fracture mechanics; Periodicals; 620.112605
• DOI: 10.1016/j.engfracmech.2018.09.034
• Languages: English
• ISSNs: 0013-7944

Abstract

Highlights: The dynamic fracture parameters of rocks under high temperature are measured. A numerical procedure of rock dynamic fracture test is developed based on the laboratory tests. Particle flow code can reproduce the mechanical behaviors of the high-temperature rock. The simulated dynamic load test is critical for the acquisition of the critical time. The loading rate effect and temperature dependence of dynamic fracture toughness are discussed. Abstract: With the limitations of measuring techniques, limited investigation on dynamic fracture testing of rocks at high temperature is reported. In this paper, an effective measuring method of the dynamic mode I fracture toughness of high-temperature rocks, combined with laboratory tests with the Discrete Element Method (DEM), is proposed. Based on the laboratory experiments conducted, including uniaxial compressive tests under different temperature conditions, the Brazilian test and split Hopkinson pressure bar (SHPB) test, the micro-parameters of the numerical model are calibrated and the validity of the numerical model of specimens and the simulated dynamic load tests are examined. The results show that the DEM can truly reflect the mechanical properties of rocks at high temperatures, and the simulation test can capture the dynamic fracture parameters of rocks at elevated temperatures. The test data indicates that the fracture initiation toughness of specimens increases linearly with the loading rate, while the fracture initiation time detected by the measurement circle near the notch tip decreases. When the loading rate is higher than 130 GPa m 1/2 /s, the fracture initiation toughness has a significantly negative relationship with the temperature within the temperature range of 25–400 °C.