Document Type : Research Article
Authors
1
Department of Mechanical Engineering of Biosystems, Faculty of Agriculture, Bu-Ali Sina, Hamadan, Iran
2
Iran Khodro Engine R&D and Manufacturing Co. (IPCo), Tehran, Iran
3
Department of Agricultural Machinery and Mechanization Engineering, Faculty of Agricultural Engineering and Rural Development, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Iran
10.22067/jam.2026.99733.1510
Abstract
Introduction
Fatigue life prediction is one of the most important considerations in machine design because it directly determines the durability and operational lifespan of mechanical components. In agricultural machinery, components are frequently exposed to harsh working environments and are often operated far from maintenance and repair facilities. Consequently, inaccurate estimation of fatigue life can lead to premature component failure, increased maintenance costs, interruptions in field operations, and significant crop losses. Despite notable improvements in both the quantity and quality of agricultural machinery manufacturing in Iran, limited attention has been devoted to the production of sugarcane harvester blades. As a result, domestically manufactured blades still do not satisfy the required quality standards. Considering the crucial role of these blades and the influence of fatigue performance under local operating conditions, including soil characteristics, moisture content, stone interference, and harvesting practices, improving blade quality is essential for reducing harvest losses. Therefore, this study investigates the fatigue behaviour of sugarcane harvester blades using finite element analysis implemented in Abaqus. Since these components are subjected to cyclic loading, their design must ensure adequate structural integrity and reliable fatigue performance throughout their service life.
Materials and Methods
Three steel grades, namely Ck60, 100Cr6, and 16MnCr5, were selected for blade fabrication because of their favourable mechanical properties, excellent hardenability, suitability for heat treatment, domestic availability, reasonable cost, and local production. Two hardening techniques, induction hardening and conventional thermal hardening, were applied to each material. The blades were manufactured according to the standard dimensions of commercial sugarcane harvesters, with a length of 28 cm and a width of 9 cm. Four different blade geometries were evaluated: conventional (old), reinforced, triangular, and crescent. Metallographic analysis was conducted to characterise the microstructure, grain size, grain boundaries, constituent phases, and chemical composition of the selected alloys. A three-dimensional model of each blade was then developed, and appropriate loading and boundary conditions were defined. Stress distribution was analysed using the finite element method, while fatigue performance was evaluated using FEMFAT software.
Results and Discussion
Metallographic examination revealed that induction-hardened 100Cr6 steel exhibited the finest grain boundaries and the most uniform microstructure among the investigated materials, which was consistent with the higher measured hardness of the induction-hardened 100Cr6 steel. Fatigue simulations were performed for four blade geometries and demonstrated that the triangular blade experienced the lowest maximum and minimum stress values. This improved stress response was attributed to more efficient load distribution, a higher moment of inertia in critical regions, reduced stress concentration, and smoother load transfer at the connection area, resulting in a more uniform stress field. Moreover, the triangular blade produced the lowest stress amplitude because its geometry effectively distributed cyclic loads and minimised stress concentrations. This characteristic is particularly advantageous from a fatigue standpoint, as stress amplitude is a primary factor governing fatigue crack initiation and propagation. In contrast, the reinforced blade exhibited the lowest mean stress owing to the presence of reinforcing ribs or increased thickness, which enhanced structural stiffness and redistributed the applied load. This reduced the overall tensile and compressive stress levels, thereby decreasing the average stress.
Conclusion
The fatigue assessment demonstrated that most of the investigated blade configurations exhibited minimal fatigue damage together with relatively high safety factors, indicating satisfactory structural performance under the simulated operating conditions. The highest stress concentration was observed at the blade attachment point to the harvester rotary plate, identifying it as the most critical location. Among the evaluated designs, the triangular blade provided the lowest calculated fatigue damage, with a damage value of 4.37 × 10⁻¹⁹ and a safety factor of 4.22. In addition, the results confirmed that the blade manufactured from 100Cr6 steel and treated by induction hardening achieved the highest measured hardness among the investigated material-hardening combinations.
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