ANSYS STRUCTURAL: Shaft Static Simulation

In this project, we performed a structural simulation of a Shaft in ANSYS Static Structural.

What are Shafts?

Shafts are the rotating elements in machinery systems used to transmit power and torque from one component to another. They are one of the main components in rotating devices, such as gearboxes, pumps, compressors, turbines, etc. Stepped shafts are one of the most widely used shaft types; the cylindrical diameter varies along its length in the form of steps, so that different parts can seat bearings or gears, with different sizes.

Geometry Definition:

We modeled the geometry of the computational domain with Design Modeler software. The computational domain corresponds to a simple long stepped shaft, composed of four coaxial cylindrical segments but having different sizes.

Mesh:

We meshed the computational domain to create a discretized domain. An unstructured grid was created, so that about 20,000 elements were generated.

ANSYS Static Structural:

There are different solvers and software available for users for structural modeling. For the present simulation, we utilize the ANSYS Static Structural Solver. The overall procedure and main steps required for static structural simulations include the definition of materials, connections, different types of boundary conditions, and post-processing.

How to define boundary conditions?

First, we defined a moment load boundary condition on the middle segments of the main shaft body, representing the twisting delivered by a gear mounted on the shaft. This moment load was applied about the central axis of the shaft. This moment load was defined as not constant, meaning it first gradually increased from zero up to a maximum value and then gradually returned to zero. It represents a short-term loading-unloading cycle. Next, we defined a fixed support boundary condition on the two cylindrical ends of the shaft, where the journals normally sit inside bearings. This constrained the horizontal shaft from the ends, so that no degrees of freedom are possible for movement.

What is the purpose of this simulation?

This investigation aims to evaluate the structural response of the shaft under loading and study the solid behavior with analysis of distributions of the total deformation, elastic strain, and von Mises stress.

Results and discussions:

The total deformation distribution indicates that maximum angular deflection occurs on the loaded middle segment of the shaft. As a torque load is applied at the middle of the shaft body and both ends are constrained without motion, the shaft twists on both sides of the loaded regions. The stress distribution indicates that the maximum stress appears near the fixed supports, where the bending moment is highest.