SU460462A1 - Method for measuring maximum stress values - Google Patents

Description

(54) METHOD OF MEASURING MAXIMUM VALUES

VOLTAGE

one

The invention of the m-device is related to measuring equipment, in particular, to the measurement of stresses on the surface of test objects.

The known method of measuring the maximum stress values on the surface of the test objects, is that the surface of the object is covered with a layer of material that changes its optical characteristics under the action of stresses, for example, a celluloid solution in a pearly essence, load the object by changing these characteristics by deciphering the resulting pictures of cracks judged by the magnitude of the stresses. However, this method is characterized by low accuracy and sensitivity of measurement, since the cracks close with time due to the plastic properties of the lacquer coating. In addition, the formation of cracks in the lacquer layer is influenced by temperature and atmospheric conditions.

To increase accuracy and sensitivity, it is proposed to cover the surface of an object with a film of a reo-chemically active material, for example, a film with a photo emulsion, to conduct chemical treatment of the film in order to reveal the latent image and to judge the magnitude of the voltage by image darkening.

When implementing the method, surfaces, for example, hydraulic machines, on which it is necessary to fix and measure the effect of stresses generated by pulses spontaneously appearing in the flow of the ambient medium, are covered with a rheologically active and unexposed film, for example, under the conditions will not be exposed to any other effects, except for subsequent flow pulses. A planned experiment or normal operation is then carried out. At the right time, the reactive film develops and

fix the latent image. Undergo a series of other operations to obtain a large-scale and contrasting pattern of the field of rheological stresses, for example, photometry, and according to the intensity of darkening

images using calibration tools (graphs, tables, etc.) translate the degree of structure change reaction into numerical stress values.

Subject invention

A method of measuring the maximum stress values on the surface of the test objects, which consists in covering the surface of the object with a layer of material. - 3. their optical characteristics, which change under the action of stresses, load the object and, by changing these characteristics, the magnitude of stresses is judged, characterized in that, in order to increase accuracy and sensitivity, the surface of the object is covered with a film of reactive material , for example, a film with a photo emulsion, chemical treatment of the film is carried out for the development of the latent image and the magnitude of the image darkening is judged by the magnitude of the stresses.