Fatigue Life Evaluation of Suspension Knuckle using Multibody Simulation Technique

Abstract

Suspension is part of automotive systems, providing both vehicle control and passenger comfort. The knuckle is an important part within the suspension system, constantly encountering the cyclic loads subjecting it to fatigue failure. This paper presents an evaluation of the fatigue characteristics of a knuckle using multibody simulation (MBS) techniques. Load time history extracted from the MBS is used for stress analysis. An actual road profile of road bumps was used as the input to MBS. The stress fluctuations for fatigue simulations are considered with the road profile. The strain-life method is utilized to assess the fatigue life. The instantaneous stress distributions and maximum principal stress are used for fatigue life predictions. Mesh sensitivity analysis has been performed. The results show that the steering link in the knuckle is found to be the most susceptible region for fatigue failure. The number of times the knuckle can manage a road bump at 40 km/hr is determined to be approximately 371 times with a 50% certainty of survival. The proposed method of using the loading time history extracted from MBS simulation for fatigue life estimation is found to be very promising for the accurate evaluation of the performance of suspension system components.

Stress and fatigue analyses under wind loading of the dual axis sun tracking system via finite element analysis

“…It also depends on the density of the air, but the variations due to these factors are assumed to be negligible specifics of each geographical region. Based on this, a maximum wind pressure (P max ) [23]:…”

“…Constant amplitude fatigue loading is defined as fatigue under cyclic loading with constant amplitude and a constant mean load. However, engineering components are usually subjected to variable amplitude loading, which can be defined by complex loading histories of varying cyclic stress amplitudes, mean stresses and loading frequencies [23,24]. There are two main approaches to fatigue life determination, i.e., the first is based on stress, the so-called Stress-Life method (S-N curve, nominal stress), also known as a Wӧhler curve while the second is based on strain, the so-called Strain-Life method (Local-Stress-Strain) [25,26].…”

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

“…Huge efforts have been made by researchers to safely assess the fatigue life of mechanical components under time-variable loadings [3]. 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 Estimation Models: A State of the Art

“…Many automotive industrial components including suspension arms, connecting rods, and train suspension springs contain defects of different sizes and geometries (AlAsady, Abdullah, Ariffin, Bedan, & Rahman, 2009;Kamal, Rahman, & Rahman, 2012;Rahman, Ariffin, Jamaludin, & Haron, 2007;Rahman, Ariffin, Rejab, Kadirgama, & Noor, 2009b;Rahman, Noor, Kadirgama, Maleque, & Bakar, 2011). 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).…”