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Alireza Shirneshan 1
1
Department of Mechanical Engineering,
Najafabad Branch, Islamic Azad University, Isfahan, Iran e-mail: [email protected]
Keywords: Simulation, Shearing strength, Shredder blade
Introduction
Today, many developed countries have wide planning to produce many devices to collect, compression and shred natural debris easier and faster due to the special emphasis on recycling and management of natural remnants. In Iran, according to too much falling of the autumn leaves in the gardens of the largest cities such as Isfahan and the request from park organizations for the devices to collect and conversion natural debris to compost and also non- production the devices in this regard, it is needed to design some equipment and machinery adapted to the conditions of each region. Natural debris shredder machine is one of the devises for this purpose. Also the shredder section is one of the main parts of the machine that the leaves and petioles as natural debris during suction shred and chip.
Research problem and research methodology Software modeling of the blade
In this research Abaqus software used to analyzing. Be- cause of considering 4 blades for natural debris shredder and working them simultaneously and similarly, one of the blades was analyzed. According to rotational motion of the blade, it has been analyzed in a rotational mode. Dur- ing the software analyzing, the characteristics and me- chanical properties of the model, model meshing, bounda- ry conditions, rotational speed and the load on the blade was applied in software. After that the results were achieved as the stress contours. were used for software analyzing of the blade.
Results
The shear strength of leaves
To apply the load on the blade in the software the shear- ing tests were done for five leaf species and the highest values for shear strength (34KPa) were recorded in Platanus orientalis followed by Morus alba Fraxinus ex- celsior and Ulmus carpinifolia. Also Salix alba had the lowest value of shear strength with 17 KPa.
Mechanical properties of the blade material
To apply mechanical properties of the blade material in the software AISI 304 was selected as the material of blade because of non rusting condition of the blade in this reserch.
Software analyzing of the blade
After software analyzing stress contours plot as results obtained. Figure (1) shows the stress contours plot of blade model.
Fig1: The stress contours plot of blade model Conclusions
As the fig (1) shows, maximum stress due to stress con- centration caused by load on the edge of the blade, related to bending and torsion, happens with amount 3.801MPa in points 2. And also minimum stress happens with amount 21.87KPa in points 1. According to the yield strength of selected material (AISI 304) that is 310MPa, results showed the blades has not been entered on plastic phase and design is without any problem.
References
1. Williams, D. J. (2005). Leaf disposal, Cooperative Extension Service, Department of Natural Resources and Environmental Sciences, College of Agricultural, University of Illinois at Urbana-Champaign, NRES- 18, PP. 1-3.
2. Somerlot, K. (2005). Composting autumn leaves, USA, Cornell Cooperative Extension of Onondaga County.
3. Sæb, A and Ferrinib, F. (2006). The use of compost in urban green areas , Urban Forestry & Urban Greening, Volume 4, Issues 3–4, PP. 159- 169.Matinkhah, H. (2006). Phenological study of thirty five tree and shrub species in Esfahan city.
Journal of Sciences and Technology of Agriculture and Natural Resources, Isfahan University of Tech- nology, 4, 503-516.
