Bartu Kurtulus

Design of a Box Transport Mechanism

ME 307


ME 307

ME 307, which stands for machine elements, is a compulsory course given to 3rd year mechanical engineering students at Middle East Technical University. This course can be considered as a continuation of the strength of materials course which taken in the second year. It starts with 3-D Stress analysis, which is the subject left unfinished in Strength. Afterwards, static and fatigue stress criteria are shown and these criteria are used to design machine elements such as shafts, permanent joints, detachable joints and mechanical springs. Since I want to prepare a detailed post about machine elements, or more precisely, structural design, I will leave the current content here. The course load includes exams, assignments and a term project. The project can be done either with a group or individually. I preferred to proceed individually in this project.

About Project

This project aims to design the box transmission mechanism. The critical position of the project, lengths and materials used are stated in the project description. What is requested from us is to identify the critical sections and examine these sections taking into account fatigue and static criteria. Afterwards, we are asked to determine the dimensions to meet the specified factory safety values. After finalizing the design with the measurements found, we are asked to make 3-D modeling. The elements I will analyze are; link, curved member, shaft, weld and pin.


Drawing free body diagrams of all elements of the mechanism and deriving force equations

Analyzing the elements and continuing by writing code for the sections where the operations are insufficient. Creating the necessary diagrams for analysis.

3-D modeling of weld, shaft and curved member according to analysis results


With this project, I applied the design concepts for different machine elements that we have seen during the term. Although there are few stages in the stages section, analysis of the parts is a very long process. If I talk about Shaft, I can say that it is the most challenging part of its design. Diameter affects many factors for design, so it is necessary to follow a hypothetical path. Using the trial and error method, it achieves results in a few tries. Although I shortened it to 3 trial, I chose this to keep the report short, otherwise it would have involved more trial and error. I leave the report below for you to review the project. I hope it will be useful to you.