Keyword: «impact bending»

In this article substantiates the relevance of research into the material of the rim of a locomotive wheel, in particular, the assessment of its cold resistance by the method of determining impact strength. A calculated FE calculation of the sharpness-deformed state of the sample during impact bending testing is carried out, taking into account the sample of plastic hardening of the material. The results of the calculation show that the accumulation and deformation of along the sample notch is contribute a localization of deformation and determinate a more rigid stress-strain state of the pre-damaged material. Thus, the impact strength of a sample made of a material of construction with a long service life decreases due to a more rigid stress-strain state, which contributes to the onset of a ductile-brittle transition at a higher temperature. A method is proposed for assessing the cold resistance of using a numerical FEM calculation of a sample for impact strength, taking into account the actualized movement of the contact samples and the stand. The causes of typical errors in solving such problems are explained.

Determination of impact strength during mechanical impact bending tests is the main practical method for assessing the susceptibility of steel to brittle fracture (GOST 9454-78). The article points out the disadvantages of this test method. Based on finite element modeling, the loading of specimens under impact bending with different types (shapes) of stress concentrator made of structural steel grade St3 was carried out. As a result of the research, a picture of the stress-strain state in the area of stress concentrators was obtained and the edge effect of stress-strain state was shown.