PSI - Issue 38

Hubert Blondet et al. / Procedia Structural Integrity 38 (2022) 526–537 Hubert Blondet, Kamilia Barthoux/ Structural Integrity Procedia 00 (2021) 000 – 000

527

2

signal (engine speed, engine load signal functions of time) into stress signals and to calculate the associated damage in each node or element of the cylinder head mesh. Like this, it is possible to determine in a list of duty cycle/customer usage, which one is the most critical regarding these thermomechanical failure modes.

D U

T Y C Y C L E History of stresses (MPa) for one node of the cylinder head mesh

Figure 1: damage calculation for one node

2. Global process of an LTA calculation For this lifetime assessment calculation (LTA) or durability analysis, several steps must be implemented to have a good estimation of the damage due to thermomechanical fatigue: - Thermal and thermomechanical simulations of several ENGINE SPEED / ENGINE LOAD pairs - Interpolation of those computed pairs to estimate the historic of stresses, based on a real duty cycle - Computation of the damage corresponding to this historic of stresses

Figure 2: Global Process - Overview