Prediction of force in interference fits for cylindrical components

• Main Author: Ho, Poo Mang
• Format: Thesis
• Language: English
• Published: 2014
• Subjects: TJ Mechanical engineering and machinery
• Online Access: http://eprints.utm.my/id/eprint/53468/25/HoPooMangMFKM2014.pdf; http://eprints.utm.my/id/eprint/53468/
• Institution: Universiti Teknologi Malaysia

Determining the forces with suitable geometrical dimension and tolerance will be finalized in engineering drawing during the typical design process. Specifically, when two cylinders are fitted, the aim is to ensure that the attached-force and detached forces are within the specified force range of 70 to 220 N. These forces are meant for the human capability to assemble and disassemble the accessories without affecting the function of the household appliances such as vacuum cleaner. Currently, attached force and detached-force testing on cylinders is carried out to determine appropriate tolerance fitting of the two cylinders. However, this method is time consuming and takes typically 162 minutes to perform. To address this issue, this research was conducted by proposing the use of mathematical equations and simulation to verify the Finite Element Analysis (FEA) model to replace the time consuming testing. A fourphase procedure was conducted. In the first phase, a test rig has been developed, test conducted and experimental data collected. In the second phase, the data was analyzed using statistical analysis and mathematical equations for attached and detached forces to be developed. In the third phase, the FEA model was developed and a comparison made between the simulated and experimental data. Finally, two case studies were carried out to monitor the behavior of attached-force should there be changes in certain parameters of the specimen. At the end of the research, a new procedure to predict the attached and detached forces of two fitted cylinders has been established. This procedure guides the designer to use either mathematical equations or FEA simulation. The mathematical equations and the FEA simulation become the design tools to replace the trial-and-error method on the testing. The design time spent in such a design work was considerably reduced to 113 minutes through the proposed design method.