PSI - Issue 5

Tatyana Tretyakova et al. / Procedia Structural Integrity 5 (2017) 318–324 Tatyana retyakova et al. / Structural Integrity Procedia 00 (2017) 0 0 – 000

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Fig. 6. (a) the stress-strain curve for the flat dog-bone specimen of the carbon steel; (b) the load-time ( I ) and temperature-time ( II ) curves for the specimen with the rhomb-shaped notch (solid line) and with the central crack-like notch (dashed line).

The study of the inhomogeneous strain fields was carried out in terms of the strain intensity along the Mises. As a result, the real (not simulated) configuration of the postcritical deformation zone has been revealed in the specimens with concentrators of different geometry. Figure 6 (b) illustrates the load-time curves of the specimen with the rhomb shaped notch (solid line) and with the central crack-like notch (dashed line). At point 1 , on the specimen surface the level of the strain intensity is reached to 20.5 %, so for the specimen with concentrator it is the beginning of the postcritical deformation stage. Although on the load-time curve we can observe the increase of the load. The experimental results are summarized in Fig. 7. The white zone indicates the region with the level of the strain intensity of ε 20.5 i  %, rewording it is the zone of the postcritical deformation of the material.

Fig. 7. Evolution of the postcritical deformation stage on the surface of the specimen with the rhomb-shaped notch and with the central crack-like notch.