Abstract:
The objective of this project was the design and fabrication of a low-cost
torsion testing machine that can be used in a mechanical lab to determine the
shear properties of materials and to serve as a means of demonstration for
students.
As the purpose of the machine is to break a standard metal specimen, high
forces in the machine have been accommodated and designed for accordingly
using a combination of theoretical and FEA analysis performed using
commercial software to ensure its structural rigidity.
The proposed design is divided into four major sections a) Transmission
System b) Sensors c) Data Acquisition d) Base frame.
The transmission system uses an enclosed cylindrical worm gear assembly
with shaft, bearings and chuck to transmit torque from a human-operated
handle to the specimen.
The base frame holds the transmission system and the secondary chuck
assembly together.
The sensors, one for measuring rotation (rotary encoder) and the other for
measuring torque (torque sensor), have been placed at both ends of the
assembly where they output the captured data to a laptop using an
Arduino/BF350 module.
The laptop makes use of a MATLAB program to calculate shear properties
from the captured data.
The report explains our approach to the design, analysis and fabrication of
each of these components and is concluded with some of the limitations that
came with the design and recommendations on future improvements.
