Theoretical Model

Authors: Jacek Tejchman

Publish Date: 2008

Volume: , Issue: , Pages: 47-85

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Abstract

This chapter describes shortly the theory of micropolar hypoplasticity including a characteristic length of microstructure in the form of a mean grain diameter First a nonpolar hypoplastic constitutive model formulated at Karlsruhe University by Gudehus 1996 and Bauer 1996 for mainly monotonic deformation paths is summarized Some results of socalled element tests oedometric compression triaxial compression cyclic simple shearing by a hypoplastic constitutive model are presented for different initial void ratios and pressure levels Next the calibration procedure for hypoplasticity to determine material parameters given by Bauer 1996 and Herle and Gudehus 1999 is outlined Later the micropolar Cosserat continuum is presented The advantages of the micropolar theory with respect to a conventional nonpolar continuum to capture shear localization are outlined The equations of a micropolar constitutive law proposed by Tejchman 1997 are given which were obtained by enhancement of a nonpolar hypoplastic constitutive law of Gudehus 1996 and Bauer 1996 by micropolar quantities Finally the FE implementation of a micropolar model in a quasistatic regime is depicted

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