Failure Analysis of Leaf Springs in Colt Diesel Canter 136 PS Vehicles: Combining Experimental and Finite Element Methods

The rear leaf spring of the Colt Diesel Canter truck exhibited signs of premature failure while carrying an 11,000 kg load over uneven and pothole-ridden roads. Therefore, a comprehensive experimental study was conducted using various analyses, which included visual observation to inspect the fractured leaf spring, followed by SEM observation to examine surface fractography. Hardness testing was also performed to determine the outer and inner surface hardness values of leaf spring, while chemical composition testing aimed to identify the material type used and its properties. Microstructure observation aimed to determine the phases present in leaf spring. This study’s numerical approach involved modelling the leaf spring in Autodesk Inventor and performing a stress analysis with the assistance of FEMAP 2022.1 software. Chemical composition analysis confirmed that the material used was AISI 52100. Visual observation confirmed the presence of an initial crack, which was validated during SEM testing. In addition, hardness testing showed average hardness values of 38 HRc and 39.344 HRc for the vertical and horizontal directions, respectively. The average hardness values for the upper and lower surfaces were 40.045 HRc and 40.63 HRc, respectively. Microstructure observation showed the presence of pearlite and cementite phases in the material. Numerical analysis yielded a stress intensity factor of 26.87 MPa·m1/2, while the crack toughness factor measured 22 MPa·m1/2 (KI > KIC), indicating the likelihood of crack propagation.