Simulation of Stress Distribution Depending on Filling and Discharge Conditions in Wheat Silo with Different Wall Thickness

Abstract

The design and development of commercially planned silos requires a strong understanding of their structural performance and loads. A limited number of studies have investigated the effect of stored products on silos. For this reason, Silo 1 and Silo 2 models with hopper base and steel construction with different wall thickness for commercial purposes were designed for storage wheat grain. For this purpose, the usability of 3, 4, 5, 7, 8, 9 and 10 mm wall thicknesses for safe storage was investigated in two different models of silos with 1306 tons and 610 tons of storage capacity. First of all, pressure loads on the model silo walls are calculated according to Eurocode 1. Then, the full-scale finite element model (FEM) of wheat silos was developed and the silos were simulated with ANSYS® software according to the filling and discharge of the product. The stored wheat and silo body interactions were modeled with minimal simplification, taking into account the characteristics of both wheat and steel silo. As a result of the research, the pressure loads in the filling and discharge conditions for both silo models increased from the top of the silo to the discharge opening. It has been determined that lower wall thicknesses are subjected to more pressure load under filling and discharge conditions. While the maximum pressure loads occurred in the funnel area in Silo 1, they occurred in the transition zone in Silo 2. As a result of ANSYS simulation, the maximum deformations for both silo models were determined in the transition zone and just below this zone. According to the results of the modal analysis, it was observed that the frequency values increased with the increase of silo wall thickness. In the light of these data, it can be said that safe and secure storage is Silo 1 and 8 mm wall thickness.

Keywords

• Steel silo
• filling
• discharge
• pressure loads
• stress

Farklı Cidar Kalınlıklarına Sahip Buğday Silosunda Doldurma ve Boşaltma Koşullarına Bağlı Olarak Gerilme Dağılımının Simülasyonu

Öz

Ticari amaçlı planlanan silolarının tasarımı ve geliştirilmesi, yapısal performansının ve yüklerinin güçlü bir şekilde anlaşılmasını gerektirir. Bu çalışmada sınırlı sayıda araştırma, depolanmış ürünlerin silolar üzerindeki etkisini araştırmıştır. Bu nedenle buğday tahılının depolaması için huni tabanlı, ticari amaçlı farklı cidar kalınlığına sahip çelik konstrüksiyonlu Silo 1 ve Silo 2 modelleri tasarlanmıştır. Bu amaçla araştırmada 1306 ton ve 610 ton depolama kapasitesine sahip iki farklı model siloda 3, 4, 5, 7, 8, 9 ve 10 mm cidar kalınlıklarının güvenli bir depolamada kullanılabilirlikleri araştırılmıştır. Öncelikle Eurocode 1’e göre model silo cidarları üzerindeki basınç yükleri hesaplanmıştır. Daha sonra buğday silolarının tam ölçekli sonlu eleman modeli (FEM) geliştirilmiş ve silolar ürünün doldurulması ve boşaltılması durumuna göre ANSYS® yazılımı ile simüle edilmiştir. Depolanan buğday ve silo gövdesi etkileşimleri, hem buğdayın hem de çelik silonun karakteristik özellikleri gözönüne alınarak, minimum basitleştirme ile modellenmiştir. Araştırma sonucunda her iki silo modelinde doldurma ve boşaltma koşullarındaki basınç yükleri silonun tepe noktasından boşaltma ağzına doğru artış göstermiştir. Doldurma ve boşaltma koşuluna göre düşük cidar kalınlıklarının daha fazla basınç yüküne maruz kaldıkları belirlenmiştir. Maksimum basınç yükleri Silo 1’de huni bölgesinde ortaya çıkarken Silo 2’de geçiş bölgesinde ortaya çıkmıştır. ANSYS simülasyonu sonucunda her iki silo modeli için maksimum deformasyonlar geçiş bölgesinde ve bu bölgenin hemen altında tespit edilmiştir. Modal analiz sonuçlarına göre silo cidar kalınlığının artması ile frekans değerlerininde arttığı gözlemlenmiştir. Çalışma sonucunda elde edilen veriler ışığında güvenli ve emniyetli depolamanın Silo 1 ve 8 mm cidar kalınlığında olduğu söylenebilir.

Anahtar Kelimeler

• Çelik silo
• doldurma
• boşaltma
• basınç yükleri
• gerilme

Kaynakça

1. ACI. (1997). Standard 313-97: Standard Practice for Design and Construction of Concrete Silos and Stacking Tubes for Storing Granular Materials. Farmington Hills, Michigan, US.
2. ANSYS Inc. (2013). ANSYS Theory Manual Release 14.0. Swanson Analysis System, USA.
3. Askegaard, V., Bergholdt, M., & Nielsen, J. (1971). Problems in connection with pressure cell measurements in silos. Bygningsstatiske Meddelelser, 2.
4. Ayuga, F., Aguado, P., Gallego, E., & Ramírez, A. (2006). Experimental tests to validate numerical models in silos design. In 2006 ASAE Annual Meeting (p. 1), American Society of Agricultural and Biological Engineers.
5. Azadi, M. R. E., & Soltani, A. A. (2010). The effects of soil-foundation-structure interaction on the dynamic response of Delijan cement-storage silo under earthquake loading. Electronic Journal of Geotechnical Engineering, 15, 659-76.
6. BIS. (1974). Criteria for Design of Reinforced Concrete Bins for the Storage of Granular and Powdery Materials. Bureau of Indian Standard.
7. Blight, G. E. (1992). Design implications of measured pressures and strains in silos. Journal of Structural Engineering, 118(10), 2729-2742.
8. Brown, C. J. (2008). Developments in the design of rectangular plan form silos. proceedings of the international conference on structures and granular solids: from scientific principles to engineering applications, The Royal Society of Edinburgh, Scotland, UK.

9. CEN. (2007). Eurocode 1: Actions on Structures, Part 4: Silos and Tanks. European Committee for Normalisation, Brussels.
10. Dooms, D., Degrande, G., De Roeck, G., & Reynders, E. (2006a). Finite element modelling of a silo based on experimental modal analysis. Engineering Structures, 28(4), 532-542.
11. Dooms, D., De Roeck, G., & Degrande, G. (2006b). Influence of the group positioning of cylinders on the wind pressure distribution in the post-critical regime. In ECCOMAS CFD 2006: Proceedings of the European Conference on Computational Fluid Dynamics, Egmond aan Zee, The Netherlands.
12. Eurocode 1. (2003). Basis of Design and Actions on Structures (EN 1991-4), Part 4: Actions in Silo and Tanks. European Committee for Standardisation, Brussels.
13. Eurocode 3. (2004). Design of Steel Structures (EN 1993-1-3), Part 1-3: General Rules- Supplementary Rules for Cold Formed Thin Gauge Members and Sheeting. European Committee for Standardisation, Brussels.
14. Gallego, E., Rombach, G. A., Neumann, F., & Ayuga, F. (2010). Simulations of granular flow in silos with different finite element programs: ANSYS vs. Silo. Transactions of the ASABE, 53(3), 819-829.
15. Goodey, R. J., & Brown, C. J. (2004). The influence of the base boundary condition in modelling filling of a metal silo. Computers & Structures, 82(7-8), 567-579.
16. Guaita, M., Couto, A., & Ayuga, F. (2003). Numerical simulation of wall pressure during discharge of granular material from cylindrical silos with eccentric hoppers. Biosystems Engineering, 85(1), 101-109.
17. Guines, D., Ragneau, E., & Kerour, B. (2001). 3D finite-element simulation of a square silo with flexible walls. Journal of engineering Mechanics, 127(10), 1051-1057.
18. Holler, S., & Meskouris, K. (2006). Granular material silos under dynamic excitation: numerical simulation and experimental validation. Journal of Structural Engineering, 132(10), 1573-1579.
19. Horabik, J., & Molenda, M. (2017). Distribution of static pressure of seeds in a shallow model silo. International Agrophysics, 31(2), 167.
20. Janssen HA (1895). Investigations of pressure of grain in silo (in German). Vereins Eutscher Ingenieure Zeitschrift, 39, 1045-1049.
21. Jayachandran, L. E., Nitin, B., & Rao, P. S. (2019). Simulation of the stress regime during grain filling in bamboo reinforced concrete silo. Journal of Stored Products Research, 83, 123-129.
22. Juan, A., Moran, J. M., Guerra, M. I., Couto, A., Ayuga, F., & Aguado, P. J. (2006). Establishing stress state of cylindrical metal silos using finite element method: Comparison with ENV 1993. Thin-Walled Structures, 44(11), 1192-1200.
23. Kibar H. (2011). Tombul fındık depolamasında tane özelliklerine bağlı olarak ANSYS programıyla optimum silo tasarımı. Doktora Tezi, Ondokuz Mayıs Üniversitesi, Fen Bilimleri Enstitüsü, Samsun.
24. Kibar, H. (2016). Determining the functional characteristics of wheat and corn grains depending on storage time and temperature. Journal of Food Processing and Preservation, 40(4), 749-759.
25. Kibar, B., & Kibar, H. (2017). Determination of the nutritional and seed properties of some wild edible plants consumed as vegetable in the Middle Black Sea Region of Turkey. South African Journal of Botany, 108, 117-125.
26. Kibar, H., & Kibar, B. (2019). Changes in some nutritional, bioactive and morpho-physiological properties of common bean depending on cold storage and seed moisture contents. Journal of Stored Products Research, 84, 101531.
27. Kovtun, A. P., & Platonov, P. N. (1959). Davlenie zerna na stenki silosov elevatorov [Grain loads on the silo walls]. Mukomolno Elevatornaia Promyshlennost, 25(12), 22-24 (Thompson ve ark. 1995’den alıntı).
28. Lapko, A. (2010). Pressure of agricultural bulk solids under eccentric discharging of cylindrical concrete silo bin. International Agrophysics, 24(1), 51-56.
29. Manbeck, H. B., Puri, V. M., & Britton, M. G. (1995). Structural loads in grain storages. DS Jayas, ND G White, and WE Muir, 465-526.
30. Mark, J., Holst, F. G., Ooi, J. Y., Rotter, J. M., & Rong, G. H. (1999). Numerical modeling of silo filling 1: Continuum analysis. Journal of Engineering Mechanics, 125, 94-103.
31. Moeini, S. A., & Ahmadian, M. T. (2009). Structural analysis of stiffened fgm thick walled cylinders by application of a new cylindrical super element. World Academy of Science, Engineering and Technology, 58, 116-121.
32. Nielsen, J. (1984). Pressure measurements in a full-scale fly ash silo. Particulate Science and Technology, 2(3), 237-246.
33. Negi, S. C., & Jofriet, J. C. (1986). Computer-aided prediction of silo-wall pressures. Applied Engineering in Agriculture, 2(2), 148-152.
34. Nielsen, J. (1983). Load distribution in silos influenced by anisotropic grain behaviour. International Conference on Bulk Materials Storage, Handling and Transportation. Newcastle, Australia.
35. Nielsen, J. (1998). The choice of constitutive laws for silo media. In C. J. Brown, & J. Nielsen (Eds.). Silos. Fundamentals of Theory, Behaviour and Design (pp. 539-550). Spon press. Newyork, USA: CRC Press.
36. Nielsen, J. (2008). From silo phenomena to load models. Proceedings of The International Conference on Structures and Granular Solids: From Scientific Principles to Engineering Applications, The Royal Society of Edinburgh, Scotland, UK.
37. Reimbert, M. L., & Reimbert, A. M. 1987. Silos. Theory and practice. Vertical Silos, Horizontal Silos (Retaining Walls). Lavoisier Publishing.
38. Singh, J., Sharma, V. R., & Khullar, N. K. (2008). Analysis of hopper bottom cylindrical silos subjected to earthquakes. In The 12th International Conference of International Association for Computer Methods and Advances in Geomechanics, Goa, India.
39. Teng, J. G., & Rotter, J. M. (1991). Strength of welded steel silo hoppers under filling and flow pressures. Journal of Structural Engineering, 117, 2567-2583.
40. Thompson, S. A., Galili, N., & Williams, R. A. (1995). Lateral pressures during filling of a full-scale grain bin. Transactions of the ASAE, 38(3), 919-926.
41. Vidal, P., Guaita, M., & Ayuga, F. (2004). Simulation of discharging processes in metallic silos. In 2004 ASAE Annual Meeting (p. 1), American Society of Agricultural and Biological Engineers.
42. Vidal, P., Guaita, M., & Ayuga, F. (2005). Discharge from cylindrical slender steel silos: finite element simulation and comparison with Eurocode 1. Transactions of the ASAE, 48(6), 2315-2321.
43. Vidal, P., Gallego, E., Guaita, M., & Ayuga, F. (2006). Simulation of the filling pressures of cylindrical steel silos with concentric and eccentric hoppers using 3-dimensional finite element models. Transactions of the ASABE, 49(6), 1881-1895.
44. Vidal, P., Gallego, E., Guaita, M., & Ayuga, F. (2008). Finite element analysis under different boundary conditions of the filling of cylindrical steel silos having an eccentric hopper. Journal of Constructional Steel Research, 64(4), 480-492.
45. Walker, D., & Blanchard, M. (1967). Pressures in experimental coal hoppers. Chemical Engineering Science, 22(12), 1713-1745.
46. Wójcik, M., Enstad, G. G., & Jecmenica, M. (2003). Numerical calculations of wall pressures and stresses in steel cylindrical silos with concentric and eccentric hoppers. Particulate Science and Technology, 21(3), 247-258.
47. Wójcik, M., Sondej, M., Rejowski, K., & Tejchman, J. (2017). Full-scale experiments on wheat flow in steel silo composed of corrugated walls and columns. Powder Technology, 311, 537-555.
48. Zheng, Q. J., & Yu, A. B. (2015). Finite element investigation of the flow and stress patterns in conical hopper during discharge. Chemical Engineering Science, 129, 49-57.