Application:

This instrument measures the fracture toughness (flexural strength) of rock materials. Fracture toughness is mainly used to classify and characterize intact rock from the perspective of crack propagation resistance. It can also be used as an indicator of rock fragmentation process (crushing tunnel excavation) and for analysis of hydraulic fracture and stability.

Technical parameter

1. The three-point bending method of cylindrical specimens with straight incisions is used to determine the fracture toughness of rocks, which is suitable for hard rocks.
2. Sample size: diameter 48mm~54mm, length is greater than 3.5~4 times of diameter ratio.
3. The ratio of the distance between the two supporting points to the diameter is 3.33.
4. The ratio of the depth of the straight incision to the diameter is 0.35~0.50 The width of the incision is not more than 1.5mm
5. Maximum load: 200kN±5N
6. Three fulcrum bending test fixture: the center position of the upper fulcrum; the distance between the lower fulcrums is 200mm (applicable to 50×50×200mm)
7. Loading rate: 3N~5KN/s
8. Loading speed: 0.001~10mm/min
9. Displacement rate: 6×10-4mm/s.
10. Stroke range: 0~10mm±0.001mm
11. Clip-on extensometer: gauge length 3.0 mm; measuring range +2.5 mm/-1.0 mm (optional)
12. Real-time LCD display and vertical load. Standard industrial computer software is used to process the acquisition force, deformation crack, expansion deformation, original data, graphic curve-deformation curve, and rock crack propagation deformation curve.
PC software