Design and fatigue characteristics of connecting rod by using finite element analysis

Abstract

In an internal combustion engine, connecting rods are usually located in between a piston and a crankshaft. Linear motion from the piston is transformed into rotational motion via the connecting rod. This research was conducted to examine the design of the connecting rod and perform finite element analysis onto the design using ANSYS programme. Several connecting rods from different engine specifications were analysed. Based on their results, the ideal design was created by drawing with the aid of the SOLIDWORKS programme. The finite element analysis method was then proceeded through the ANSYS Workbench software. The analysis of the impact of the stress distribution and concentration was also performed. The objective of this study was to perform simulation on connecting rods with two different materials and analyse their performances based on similar conditions by the means of design optimization. The main criteria to be analysed is the fatigue analysis and the performance of the connecting rod. Two different materials, steel alloy and titanium alloy were assigned to the same design. The simulation was performed using the static structural programme in ANSYS with the condition of a static loading condition. Two separate simulations and analysis were performed for both cases of material. The titanium alloy connecting rod provided with better results in terms of stress analysis and fatigue life compared to the steel alloy. Therefore, the modification was performed onto the design structure while retaining the material as steel alloy. The study shows results of two working designs that were modified which provides with positive results. The simulation process was performed onto the modified design, New Design 1, where a slope 10° is cut at the segment between the small end and the I-beam of the connecting rod. The results obtained were compared with the results of the original design connecting rod with steel alloy material. The results show improvements which helps increase the strength and life of the structure. Design optimization of the modified design was performed, where certain changes to the dimensions of New Design 1 was made. The newer design, New Design 2, where the slop is modified to 15°, underwent the same simulation and analysis steps and results were compared with the original design of the structure and New Design 1. The results obtained showed better improvement in terms of stress distribution and fatigue life. This concludes that New Design 2 is able to withstand much higher amount of stress compared to the other two structures. The modification of the structure is considered successful as it provides with improvements to the results of the original design.