46. Symposium "Actual Tasks on Agricultural Engineering", Opatija, Croatia, 2018. 201 FEM MODELLING OF MACHINERY INDUCED COMPACTION FOR THE SUSTAINABLE USE OF AGRICULTURAL SANDY SOILS Nicoleta UNGUREANU 1 *, Valentin VLĂDUŢ 2 , Sorin-Ștefan BIRIȘ 1 , Gigel PARASCHIV 1 , Mirela DINCĂ 1 , Bianca Ștefania ZĂBAVĂ 1 , Vasilica ȘTEFAN 2 , Nelus Evelin GHEORGHIȚĂ 1 1 Department of Biotechnical Systems, Faculty of Biotechnical Systems Engineering, University Politehnica of Bucharest, Splaiul Independentei Blv., no. 313, sector 6, Bucharest, Romania 2 National Institute of Research - Development for Machines and Installations Designed to Agriculture and Food Industry – INMA, Ion Ionescu de la Brad Blv., no. 6, sector 1, Bucharest, Romania E-mail of corresponding author: nicoletaung@yahoo.com SUMMARY The anthropogenic compaction of agricultural soil depends mainly on the type of soil, soil moisture, wheel load, tire inflation pressure, size and shape of footprint area, contact pressure and number of passes. This paper aims to assess the depth to which soil compaction would occur, by modelling the distribution of stresses and displacements in sandy soil under wheel loads applied by an agricultural trailer. Modelling by Finite Element Method was performed in the Quickfield Student program using the 2D geometric model of plane load. For known characteristics of the soil, at various wheel loads (4.5, 13 and 21 kN) and tire inflation pressures (180, 240 and 300 kPa) were obtained the models of stress distribution in soil depth and the models of soil displacement. It was also obtained the stress in increments of 100 mm in soil depth. The models show that for 4.5 kN and 13 kN wheel loads, regardless tire inflation pressure, the topsoil would become compacted, while 21 kN wheel load, at 240 kPa and 300 kPa increases the risk of subsoil compaction. Keywords: compaction, wheel load, tire inflation pressure, stress, displacement. INTRODUCTION Human interventions in the use of the world’s natural resources are resulting in their degradation, with long term consequences. Soil is a vital part of every ecosystem and one of 46. SIMPOZIJ AKTUALNI ZADACI MEHANIZACIJE POLJOPRIVREDE Izvorni znanstveni rad Original scientific paper