Summary
In a previous paper [1] we introduced the concept of a loading surface which is distinct from and encloses the yield surface. The region between the two surfaces may be called the microstrain region. In this paper experiments with pure aluminium are presented in which the influence of repeated loading on the microstrain region is explored. It is seen that the microstrain region decreases in size with each cycle but that it does not necessarily become zero even after several cycles. It is also shown that the yield surface does not enclose the origin even at small values of plastic strain. At the end of the paper it is shown that considerable care should be exercised in the determination of the yield surface since in some cases its position and shape can be influenced to a considerable extent by the unavoidable penetration inside the plastic region while probing for it.
Zusammenfassung
In einer vorangegangenen Arbeit [1] haben wir das Konzept einer Belastungsfläche eingeführt, die verschieden ist von der Fließfläche, diese aber umschließt. Der Bereich zwischen den beiden Flächen soll Mikroverzerrungsbereich genannt werden. In dieser Arbeit werden Versuche mit reinem Aluminium angegeben, in welchen der Einfluß wiederholter Belastung auf den Mikroverzerrungsbereich untersucht wird. Es ist ersichtlich, daß der Mikroverzerrungsbereich mit jedem Belastungszyklus kleiner wird, aber er schrumpft auch nach oftmals wiederholten Belastungszyklen nicht notwendigerweise auf Null zusammen. Es wird ferner gezeigt, daß die Fließfläche den Ursprung nicht beinhaltet, auch nicht für kleine Werte der plastischen Verzerrung. Am Ende der Arbeit wird gezeigt, daß eine gewisse Sorgfalt bei der Bestimmung der Fließfläche nicht außer acht gelassen werden darf, da in einigen Fällen ihre Lage und Gestalt bis zu einem gewissen Grade durch das unvermeidliche Eindringen in die plastische Region während des Experiments beeinflußt wird.
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This work was sponsored by the National Science Foundation of the United States Government.
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Sierakowski, R.L., Phillips, A. The effect of repeated loading on the yield surface. Acta Mechanica 6, 217–231 (1968). https://doi.org/10.1007/BF01170386
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DOI: https://doi.org/10.1007/BF01170386