This presentation was made at the NAFEMS Eastern European Seminar "Engineering Analysis & Simulation in the Automotive Industry" held on the 7th of November in Bucharest.

Automotive manufacturers and suppliers are constantly challenged with delivering innovative, safe, and dependable vehicles to market as efficiently as possible. As a result, engineering teams must discover, evaluate, and successfully implement leading-edge technology and methods to produce a reliable, effective outcome. Many of these efforts now come together under concepts such as Industry 4.0, Digital Twin, CAE Democratization, and Cloud Solutions. But what do these really mean for you, as a simulation specialist?

Resource Abstract

Historically there are different conventional methods used to calculate fatigue life. The strain life method (EN) describes the fatigue life until crack initiation. Linear elastic fracture mechanics (LEFM) methods calculates the crack growth to the fracture of a part. A stress life method (SN) is used for estimating fatigue life of a parts from new, through cracking to fracture and therefore mostly used in the high cycle fatigue regime.



This presentation illustrates a new approach “WholeLife”, which delivers more accurate prediction of weld fatigue compared to conventional SN methods. The WholeLife fatigue analysis process combines the effects of crack initiation (EN) with the macroscopic crack growth (LEFM) to the final fracture. It overcomes the limitation of classical fatigue calculation by combining the crack initiation and the crack growth approaches. The fundamentals of WholeLife model are similar to a linear elastic fracture mechanics model, but the LEFM suggest an infinitely sharp crack, while WholeLife assumes a blunt crack of tip radius ρ*. This material fitting parameter is assumed to be a similar size to the grain size of the material, prevents stress singularities and overcome problems of modelling small fatigue cracks. A comparison study with the conventional methods show that the method delivers more accurate fatigue life results. It could be an alternative to existing methods to improve product durability, lightweight designs, to reduce overdesign and costs.