METHOD OF MEASURING HARDNESS AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2018 - IPC G01N3/40 

FIELD: measuring equipment.

SUBSTANCE: end of the rod acoustic resonator is provided with an indenter; the rod acoustic resonator is excited at the resonant frequency. The indenter is placed on the monitored surface, a fixed load is applied to it and the excitation frequency is recorded. In addition, a smoothly increasing load is applied to the indenter, the load is measured and stored in time, the measurement and storage of the corresponding resonant frequencies of the rod acoustic resonator are measured and stored simultaneously with the load measurement. The frequency differences of the rod acoustic resonator under load and without load are determined. They are used to calculate the hardness at different loads, estimate the steepness of the curve of the change in the applied load in time for tracking and adjusting its rate of rise during the measurement and recording the hardness value for the required load. The device includes a housing, a rod acoustic resonator with a support disk, an indenter, located on the end of the rod acoustic resonator, a load spring, piezo transducers, a generator, a control unit and an input/output device, with the input and the first output of the generator connected to the piezo transducers, the second output connected to the control unit, the output of which is linked to the input-output device. In addition, a linear sensor of the applied load, a storage unit for measured force values and corresponding frequencies of the acoustic resonator, and a cylindrical holder are provided. Wherein the rod acoustic resonator is fixed with a support disk in a cylindrical holder which is mounted in a bearing with the possibility of moving along the housing. The load spring is mounted coaxially with the housing between the end face of the cylindrical holder and the working surface of the linear load cell. The supporting surface of the linear load cell rests against the internal end surface of the housing, and the output of the linear load cell is connected to the input of the control unit, which is connected to the storage unit for measured force values and corresponding frequencies of the acoustic resonator.

EFFECT: increasing the accuracy of hardness measurement, expanding the scope and increasing the reliability of the results of assessing the technical and operational status of complex structures and their elements.

2 cl, 5 dwg, 1 tbl