Browsing by Author "Hlebová, Stanislava"
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- ItemComparison Of Deformation Characteristics Of The Steel Sheet In Local And Global Area By The Static Loading Using Videoextensometry(Chemické Listy, 2011) Hlebová, Stanislava; Pešek, Ladislav; Kandra, TomášTwo steel sheets used for deep drawing of the compressor cover were investigated using the videoextensometry technique for strain monitoring during tensile test. The material causing cracks during deep drawing has higher both yield stress and strength and lower ductility comparing with material without problems in technology. The strain hardening exponent n is increasing in the strain interval up to just before R-m, while the values measured in local area were lower than values measured in global area. The plastic strain ratio is decreasing for both materials measured in local and global area.
- ItemDetermination of Plastic Zone by UCI Technique on Thin Steel Sheets(2010) Ambriško, Ľubomír; Pešek, Ladislav; Hlebová, StanislavaThe main goal of this paper is the determination of the size and shape of the plastic zone in thin steel sheets. The aim of experiments was to analyze the influence of the material and type of the initial crack on the dimensions of the plastic zone. The plastic zone size and shape is also predicted by measuring hardness (HV 1) along and across the unbroken ligament. The hardness is measured by using UCI (Ultrasonic Contact Impedance) technique. The hardness values varied in dependence on the material and the initial crack. In this paper, the CT (Compact Tension) specimens of two steel grades with a notch and with an electrospark produced notch were used. Specimens were loaded by eccentric tension, whereby the deformation in the area around the notch was recorded by non-contact displacement measurement - a videoextensometry technique.