Simulation of static stress distribution of wheat piles in silos by the modified Cam-clay model
Mengyao Gao 1
Xuduo Cheng 1, 2, 3  
Meizhu Hu 2
Xiaocui Du 1, 2
More details
Hide details
College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing, China
Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing, China
Department of Food Science and Engineering, Nanjing University of Finance and Economics, 3 Wenyuan Road, Nanjing 210046, Jiangsu Province, China
Publish date: 2019-02-06
Acceptance date: 2018-01-05
Int. Agrophys. 2019, 33(1): 11–19
Static stress of granular materials stored in silos is important for the security of materials during storage. Janssen equation was commonly used to calculate the static stress of grains in silos, but later researchers found the equation underestimated loads in storage bins. In this paper, the modified Cam-clay model was applied to study the stress distribution of wheat piles at four moisture levels, stored in a circular flat bottom silo, at different grain depth and radius of silos. The results showed that as the grains depth increased, the vertical stress of wheat piles increased except the wall-bottom of silos, and the lateral stress increased except the center of silos near bin bottom. Moreover, it was found that as the radius increased, the vertical stress of wheat piles decreased at the same depth and moisture content, and the lateral stress decreased but increased near the bin bottom in the same case. When the mean stress of a layer of grains were observed, it was found that the lateral stress was negatively correlated with moisture content when the vertical stress had no concern with it at the same grain depth and all of them approached the maximum at the same moisture content.
1. ASAE Standards, 2001. Moisture measurement-unground grain and seeds. Am. Soc. Agri. Eng., 567-568.
2. Ayuga F., Moya M., Guaita M., and Aguado P., 2002. Mechanical properties of granular agricultural materials. Trans. ASAE, 45(5), 1569-1578.
3. Ayuga F., Moya M., Guaita M., and Aguado P., 2006. Mechanical properties of granular agricultural materials, part 2. Trans. ASABE, 49(2), 479-489.
4. Bishara A.G., Ayoub S.F., and Mahdy A.S., 1983. Static pressures in concrete circular silos storing granular materials. ACI Jnl., 80(3), 210-216.
5. Chen X.G., Yang G.H., and Yang X.H., 2011. Soil constitutive models. Beijing: China Water Power Press, 8-92.
6. Cheng X.D., Lu L.L., and Shi C.X., 2012. The experimental research on friction properties of wheat. J. Chin. Cereals Oils Assoc., 27(4), 15-19.
7. Cheng X.D., Zhang Q., Shi C.X., and Yan X.J., 2017. Model for the prediction of grain density and pressure distribution in hopper-bottom silos. Biosyst. Eng., 163, 159-166.
8. Drescher A. and Vgenopoulou I., 1985. A theoretical analysis of channeling in bins and hoppers. Powder Technol., 42(2), 181-191.
9. Du X.C., Yan X.J., Cheng X.D., Gao M.Y., and Feng J.C., 2017. Model of Density and Pressure Distribution of Paddy in the Hopper-Bottom Silo. J. Chin. Cereals Oils Assoc., 32(5), 102-109.
10. FAOSTAT, 2014. Agricultural Data. FAO. Rome: Online at
11. Gong X.N., 1999. The soil plasticity. Hangzhou: Zhejiang University Press, 246-250.
12. Goodey R.J., Brown C.J., and Rotter J.M., 2017. Rectangular steel silos: Finite element predictions of filling wall pressures. Eng. Struct., 132, 61-69.
13. Hatfield F.J. and Bartali E.H., 1988. Static forces and moments in a grain silo. J. Struct. Eng., 114(12), 2814-2819.
14. Haque E., 2013. Estimating bulk density of compacted grains in storage bins and modifications of Janssen’s load equations as affected by bulk density. Food Sci. Nutrition, 1(2), 150-156.
15. He Z., Rajaram S., Xin Z., and Huang G., 2001. A History of Wheat Breeding in China. CIMMYT, Mexico. Hibbit, Karlsson, Sorenson Inc., 2001. ABAQUS/Explicit: User’s Manual, Version 6.2.
16. Janssen H.A., 1985. Versuche über getreidedruck in silozellen. Zeitschriff des Vereines Deutscher Ingenieure, 39, 1045-1049.
17. Jofriet J.C., Lelievre B., and Fwa T.F., 1977. Friction model for finite element analyses of silos. Trans. ASAE, 20(4), 735-740.
18. Li X.J., Cao Z., Wei Z.Y., and Fen Q.Y., 2011. Equilibrium moisture content and sorption isosteric heats of five wheat varieties in China. J. Stored Prod. Res., 47(1), 39-47.
19. Luo D., Yao Y.P., and Hou W., 2010. Soil Constitutive Models. China Communications Press, Beijing, 78-82.
20. Lvin J.B., 1971. Analytical evaluation of pressures of granular materials on silo walls. Powder Technol., 4(5), 280-285.
21. Mahmoud A. and Abdel-Sayed G., 1981. Loading on shallow cylindrical flexible grain bins. J. Powder Bulk Solids Tech., 5(3), 12-19.
22. Roberts A.W., 1998. Particle technology-reflections and horizons: An engineering perspective. Chem. Eng. Res. Des., 76(7), 775-796.
23. Rooda J.E. and Haaker G., 1977. A testing procedure for triaxial tests and a numerical method for the calculation of powder flow properties. Powder Technol., 16(2), 273-280.
24. Smith D.L.O., 1981. The triaxial load response of grain. Ph.D. Thesis, Iowa State University, Ames, IA, USA.
25. Su L.Y., 1997. Stress analysis of grain static pressure in vertical silo. J. Zhengzhou Grain College, 18(3), 72-76.
26. Suebsuk J., Horpibulsuk S., and Liu M.D., 2010. Modified Structured Cam Clay: A generalised critical state model for destructured, naturally structured and artificially structured clays. Comput. Geotech., 37(7-8), 956-968.
27. Thompson S.A. and Ross I.J., 1983. Compressibility and frictional coefficients of wheat. Trans. ASAE, 26(4), 1171-1176.
28. Tripodi M.A., Puri V.M., Manbeck H.B., and Messing G.L., 1994. Triaxial testing of dry, cohesive powder and its application to a modified Cam-clay constitutive model. Powder Technol., 80(1), 35-43.
29. Vidal P., Gallego E., Guaita M., and Ayuga F., 2008. Finite element analysis under different boundary conditions of the filling of cylindrical steel silos having an eccentric hopper. J. Constr. Steel Res., 64(4), 480-492.
30. Walters J.K., 1973. A theoretical analysis of stresses in silos with vertical walls. Chem. Eng. Sci., 28(1), 13-21.
31. Yin W., Lu Y., and Jin Y.O., 2014. Finite element modelling of wall pressures in a cylindrical silo with conical hopper using an Arbitrary Lagrangian-Eulerian formulation. Powder Technol., 257(5), 181-190.
32. Zhang Q., Puri V.M., and Manbeck H.B., 1986. Determination of elastoplastic constitutive parameters for wheat en masse. Trans. ASAE, 29(6), 1739-1746.