Fatigue Life Prediction of a Drag Link by Using Finite Element Method

Abstract

The focus of this study is to find fatigue behavior and fatigue life of a drag link in the different road and loading conditions. Finite element method was used for fatigue analysis and fatigue life of the drag link was predicted. Firstly, the historical changes in the concept of the fatigue and fatigue life calculation methods were explained in the chapter one and two. Factor affecting the fatigue performance was explained. Stress and strain based fatigue analysis methods were described clearly. Finally, fatigue life analysis in the frequency domain which is a new method relative to the others was explained. Then, two different steering drag links of a midibus were examined and fatigue life calculations of these two drag links were made. The fatigue life analysis in the time domain of the drag links were made in the static steering conditions and the results were compared with the test results made by the vendor of the drag links. After that, the drag link which has a greater fatigue life than the other was selected, the road loads were taken from another test report which was made by using the same drag link and the fatigue life of the drag link was computed by using the finite element method in the time domain. Finally, the same road loads were converted in the frequency domain and the fatigue life analysis of the same drag link were made in the frequency domain. The results from the time domain and the frequency domain were compared and the advantages of the fatigue life analysis in the frequency domain were expressed.

Automated sizing of automotive steering ball joints in parametric CAD environment using expert knowledge and feature-based computer-assisted 3D modelling

“…The design results obtained by the PDP were very close to the off-the-shelf neck diameter and the result may be considered reasonable since the OEM manufacturers' design factor is not known due to commercial reasons. As a comparison with existing literature, some of the studies [6,7,15,17] focused on FEA based on a loop that analysed the design and then changed parameters manually without automated correction on those parameters. On the other hand, studies on feature-based CAD systems [18 to 28] focused on the alteration of parts in an assembly without applying engineering calculations for sizing.…”

“…However, few studies have focused on the FEA and metallurgical structure of ball joint part materials under failure conditions [6,7,16]. Koca and Ekici [17] have analysed fatigue behaviour of draglinks used in steering system with both finite element analysis (FEA) method and an experimental test rig. However, FEA is an analysis tool used within all phases of product development process but it is not a design tool.…”

Investigation of the Effect of Bending Process on Fatigue Life and Mechanical Strength of Heavy Commercial Vehicle Drag Links

“…In case the vehicles encounter different road conditions, various tensile and compressive stresses may occur on the drag link. These variable stresses produce fatigue, causing microcracks to occur, and the tie rod may be damaged by cracking in the future [2]. DP600 steel material with pre-strain applied in different directions has higher yield strength and fatigue resistance than material without prestrain [3].…”

The Effect Of Drag Link Bending Radius On Fatigue Life And Static Forces Strength

“…Tensile and compressive stresses may occur on the drag link under different road conditions. The stresses cause fatigue, causing micro-cracks to form, and the drag link can be damaged by cracking in the future (Koca & Ekici, 2010). The bending of the pipes from the errors seen in the drag link is due to the buckling error of the pipe against the compression loads (Doke & Shaikh, 2016).…”