METHOD OF DETERMINING STRENGTH OF MATERIAL Russian patent published in 2020 - IPC G01N3/32 G01N3/40 

FIELD: soil or rock drilling; mining.

SUBSTANCE: invention relates to physical and mechanical testing of materials, particularly rocks, can be used in engineering-geological survey and provides determination of ultimate strength of material at compression without destruction of sample. Essence: indenter of variable cross-section is continuously pressed with continuously increasing load to maximum value of arbitrary value, after which the impression is stopped and sample is unloaded to zero value. Magnitude of the load and the corresponding displacement depth of the indenter are recorded, and the pressure on the contact surface between the indenter and the sample is calculated in the period of increasing load. Indenting and unloading of the indenter is performed without changing its position in a cyclic manner, providing in each subsequent cycle a discrete increase in the maximum load value at which unloading begins. During sample unloading, pressure is determined on contact surface by ratio of load on indenter to maximum area of contact surface in each cycle. In each cycle, also for the same depth of the indenter displacement, the difference between the pressure on the contact surface during the load increase and the pressure during the unloading period is calculated, and the maximum value of the difference of the said pressures is determined. Tests are continued until formation of horizontal section on graph of relationship between maximum values of pressure difference and corresponding load values. Value of pressure difference corresponding to horizontal section is taken as ultimate strength of material at compression loads.

EFFECT: technical result is possibility of determining ultimate strength of material during compression without destroying sample.

1 cl, 4 dwg