Design of Transmission Shafts – Stress Analysis

JoVE 核
Mechanical Engineering

JoVE 核 Mechanical Engineering
Design of Transmission Shafts – Stress Analysis

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The design of a transmission shaft involves understanding the stresses due to bending moments and torques.

When power is transferred through gears, the forces exerted equate to force-couple systems applied at cross-section centers, which subject the shaft to both transverse and torsional loading.

Although shearing stresses from transverse loads are smaller than those produced by torques and often neglected, the considerable normal stresses from transverse loads contribute significantly to the maximum shearing stress.

The normal stress exerted on the section is computed by examining a shaft's cross-section at a specific point and accounting for both the torque and bending couples.

The maximum normal stress occurs at the end of the diameter perpendicular to the resultant of the bending moment couple.

The minimum allowable polar moment ratio for the cross-section is determined by considering both the maximum resultant bending moment and torque in the shaft, along with the allowable shearing stress.

This approach facilitates the design of both solid and hollow circular shafts.

Design of Transmission Shafts – Stress Analysis

Designing a transmission shaft requires a thorough understanding of the stresses induced by bending moments and torques, especially in systems where power is transferred through gears. These forces create force-couple systems at the centers of the shaft's cross-sections, leading to both transverse and torsional loading. Although shearing stresses from transverse loads are typically smaller than those from torques and are often overlooked, the significant normal stresses from these loads contribute to the maximum shearing stress.

Calculating the normal stress exerted on a shaft section involves examining the shaft's cross-section at a specific point, considering both the torque and bending couples. The maximum normal stress typically occurs at the ends of the diameter perpendicular to the resultant of the bending moment couple. Determining the cross-section's minimum allowable polar moment ratio J/c is essential to ensure the shaft's integrity and functionality.

This ratio is vital as it accounts for both the maximum resultant bending moment and torque on the shaft, in addition to the allowable shearing stress. This analytical approach is fundamental in designing both solid and hollow circular shafts, enabling the creation of optimized shaft configurations that can reliably withstand operational stresses. Such methodology ensures that the designed shafts are robust, efficient, and tailored to their specific applications, guaranteeing mechanical systems' safety and functionality.