Design, Stress Analysis, and Material Comparison of Helical Gear Pair Using Analytical Method and ANSYS Finite Element Analysis for Industrial Gearbox Application

Abstract

Helical gears are the most widely used gear type in industrial power transmission applications, preferred over spur gears for their quieter operation, higher load carrying capacity, and smoother torque transmission arising from the gradual meshing of helically disposed teeth. The design of helical gears for industrial gearbox applications requires simultaneous consideration of bending strength (tooth root failure), contact strength (pitting of tooth flanks), deflection underload, and material selection — with the optimal material providing adequate strength and safety factor at minimum mass and cost. This paper presents the complete analytical design and finite element analysis (FEA) of a helical gear pair for a 5 kW, 1000 rpm industrial gearbox application with a 3:1 gear ratio, comparing three candidate gear materials: Cast Iron Grade 25, Steel EN 24 (40Ni2Cr1), and 20MnCr5 alloy steel. Gear geometry is designed using the Lewis bending strength equation and AGMA contact stress analysis following IS 2535:1978 guidelines. ANSYS Mechanical 2024 R2 with SOLID186 elements is used for three-dimensional FEA to determine bending stress, contact stress, total deformation, and safety factors under the design torque with service factor. Results show that Cast Iron Grade 25 fails to provide adequate safety factors at the design load (FOS_bending = 0.46, FOS_contact = 0.83) for this power level. Steel EN 24 provides marginal bending safety (1.40) with acceptable contact safety (1.60), while 20MnCr5 alloy steel achieves the best safety factors (FOS_bending = 1.77, FOS_contact = 2.09) with minimum deformation (0.0186 mm) and 43.7% mass reduction overcast iron due to the smaller module enabled by its higher allowable stresses. 20MnCr5 is recommended as the optimal material for this application, providing superior structural performance and significant weight reduction at moderate cost premium overcast iron.

Cite as:

Snehal Lomate. (2026). Design, Stress Analysis, and Material Comparison of Helical Gear Pair Using Analytical Method and ANSYS Finite Element Analysis for Industrial Gearbox Application. Research and Reviews: Journal of Mechanical Engineering, 2(2), 40–50. https://doi.org/10.5281/zenodo.21872735