Application of Multibody Simulation for Fatigue Life Estimation

Abstract

In automobile design, the safety of passengers is of prime concern to the manufacturers. Suspension is one of the safety-related automotive systems which is responsible for maintaining traction between the road and tires, and offers a comfortable ride experience to the passengers by absorbing disturbances. One of the critical components of the suspension system is the knuckle, which constantly faces cyclic loads subjecting it to fatigue failure. This paper presents an evaluation of the fatigue characteristics of a knuckle using a gravel road profile acquired using a data acquisition system and standard SAE profiles for the suspension (SAESUS), bracket (SAEBRAKT) and transmission (SAETRN). The gravel road profile was applied as the input to a multi body simulation (MBS), and the load history for various mounting points of the knuckle is extracted. Fatigue life is predicted using the strain-life method. The instantaneous stress distributions and maximum principal stress are used for fatigue life predictions. From the results, the strut connection is found to be the critical region for fatigue failure. The fatigue life from loading extracted from gravel road MBS agreed well with the life prediction when standard SAE profiles were used. This close agreement shows the effectiveness of the load extraction technique from MBS. This method can also be effectively used for more complex loading conditions that occur during real driving environments.

Dynamics properties of a Go-kart chassis structure and its prediction improvement using model updating approach

“…There are quite a number of studies that have been carried out concerning go-karts. This includes the study about the design of its frame or chassis that sometimes were concerned about the selection of materials for the structure, simple structural analysis, safety, and also the stability of the structure [1][2][3][4]. Currently, the trend in chassis design is focusing on producing lower cost and lighter vehicle structure but with good safety efficiency.…”

“…Furthermore, finite element model updating is already considered as an important subject to design, in terms of construction and maintenance of mechanical systems and civil engineering structures [10] since it is viewed as a convenient tool for analysing and predicting the dynamic performance of various structures [11][12][13][14][15]. For example, Mottershead and Friswell with their partners have done quite a study of model updating using FEA and have proven the reliability of finite element model in providing desired outcomes [4,[16][17][18][19]. The EMA is the classic method of obtaining the modal parameter of a certain structure [20].…”

Fatigue Life Estimation Based on Continuum Mechanics Theory With Application of Genetic Algorithm

“…Correctly estimating fatigue life in real components is a complex process having a large number of variables to deal with to avoid unwanted and critical failures [4,5]. The reliability of a fatigue estimation technique depends on its ability to model damage due to non-zero superimposed static stresses, the degree of multiaxiality in the stress field and effects of stress concentration phenomena [6][7][8][9]. Fatigue life is difficult to estimate especially in the cases of cyclic or random multiaxial loading conditions, as damage depends on all of the stress components and their variations during the whole time period of load application [6,10].…”

Fatigue Life Estimation Models: A State of the Art

“…Some of these components are classified as safety components and thus they have to be subjected to particular attention during fatigue design in order to guarantee an appropriate in-service durability with light-weight design (Abdullah, Beden, Ariffin, & Rahman, 2008;Kamal, Rahman, & Sani, 2013;Rahman et al, 2008;Rahman, Ariffin, Jamaludin, & Haron, 2006). Hence, the problem of high-cycle fatigue life estimation of components containing defects is of great importance from a social, scientific and industrial point of view (Rahman, Ariffin, Jamaludin, & Haron, 2005;Rahman et al, 2007;Rahman, Ariffin, Rejab, Kadirgama, & Noor, 2009c).…”