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An investigation of nonlinear tangential contact behaviour of a spherical particle under varying loading

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Zabulionis D. , Kacianauskas R. , Markauskas D. , Rojek J.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2012

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tom Vol. 60, nr 2

265-278

EN

An analytical and numerical study of the tangential contact of a spherical particle under varying combined normal-tangential loading is presented. The normal and tangential contact is described by the Hertz and regularized Coulomb laws. This study is focused on the analysis of the tangential displacement of the particle’s contact point under variable normal force and reevaluation of the procedures for calculation of the tangential force. The incremental displacement-driven and force-driven constitutive relationships are developed. The importance of an adequate numerical treatment of the tangential component of the contact force is shown for the slide mode, and the recommendations for its evaluation are proposed. The performance of the algorithm is demonstrated by solving the problem of the oblique impact of the spherical particle on the wall. The suggested methodology allows us to analyse the elastic and sliding effects of the tangential interaction more precisely than existing methodologies. Besides, the issue of the direction of the tangential force, when the Coulomb limit is reached, was reconsidered in one-dimensional case by taking three versions of the unit direction vector, which are based on the tangential elastic displacement, tangential stick force, and tangential relative velocity of the contact point of the particle.

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Simulation of piezocone penetration in saturated porous medium using the FE remeshing technique

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Markauskas D. , Kacianauskas R. , Katzenbach R.

Foundations of Civil and Environmental Engineering

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2005

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tom No. 6

103-116

EN

The simulation of piezocone penetration in saturated soil modelled as porous medium has been presented herein. The non-linear transient coupled soil-pore fluid model and the finite element method (FEM) have been applied. To handle very large distortion of medium surrounding the cone tip, a finite clement remeshing technique for deformed domain involving combined transfer of the state variables has been developed. The moving least square method was utilized for the transfer of Gauss points variables while the simple interpolation method was used for the transfer of nodal points variables. This technique was implemented into the post-processor type software compatible with a standard FEM code. The proposed remeshing technique enables the simulation of the penetration process with penetration depth of several diameters until steady state penetration is reached. The validity of the remeshing is justified by comparing the simulation results in porous and homogeneous media.

3

Modelling the cone penetration test by the finite element method

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Markauskas D. , Kacianauskas R. , Suksta M.

Foundations of Civil and Environmental Engineering

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2002

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tom No. 2

125-140

EN

In the present study, CPT is modelled by static elasto-plastic small strain finite element method (FEM) analysis of axi-symmetric problem. Undrained soil properties and Tresca yield criterion is used for determining cone resistance of clay. Sand is modelled by using drained soil properties and Mohr-Coulomb yield criterion. Cone penetration problem is formulated as a collapse load problem. Associated and non-associated flow rules were used for modelling A number of the numerical experiments were performed to determine rational size of discrete region. Received dimensions of region were used for further research. Cone factor Nc for clay was obtained and the comparison of Nc values with other theoretical solutions is presented. A conclusion may be made that the limit of the validity of geometrically linear systems has been reached. The evaluation of the effect of cone penetration requires the analysis of large strains to be made.

PL

W pracy przedstawiono numeryczne modelowanie zjawiska penetracji stożka w gruncie. Wykonano je, stosując metodę elementów skończonych. Do obliczeń zastosowano teorię małych odkształceń sprężysto-plastycznych. Wyniki podano, wykorzystując w analizie osiową symetrię zjawiska. Badano efekty penetracji stożka w dwóch rodzajach gruntów: w glinie i w piasku. Dla ustalenia oporu penetracji stożka w glinie traktowanej jako grunt odwodniony zastosowano warunki plastyczności Treski. Piasek był modelowany jako grunt nawodniony, do którego opisu zastosowano warunki plastyczności Mohra-Coulomba. Penetrację stożka rozważano jako problem wyznaczenia wartości obciążenia prowadzącego do uplastycznienia gruntu. Otrzymane rezultaty porównano dla przypadków modelowania zjawiska z zastosowaniem stowarzyszonego i niestowarzyszone prawa płynięcia. Celem eksperymentów numerycznych było również określenie maksymalnych rozmiarów strefy gruntu otaczającej stożek, której dyskretyzacja wystarczała do dokładnego opisu zjawiska. Wyniki badań numerycznych porównano z innymi przedstawionymi w cytowanej literaturze. Określono również zakres ważności przyjętej do modelowania teorii małych odkształceń.

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An investigation of nonlinear tangential contact behaviour of a spherical particle under varying loading

75%

Zabulionis D. , Kačianauskas R. , Markauskas D. , Rojek J.

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