Fatigue design by simulation - Application example

To meet the challenges of the industry of the future, the design of mechanical components subject to cyclic and multiple stresses requires a thorough understanding and control of all failure modes and associated mechanisms. Examples include loading mechanisms and their combinations (thermal, mechanical, in-phase, counter-phase), material properties and manufacturing processes (residual stresses, porosity). To compensate for the complexity of taking such phenomena into account, the design of these components was based on comfortable safety margins.

With the progress made in simulation tools and testing techniques over the last few decades, optimizing the design and performance of mechanical parts has become a major market demand. The development of internal combustion engines, with a significant reduction in the number of iterations required to make the various components reliable, is a concrete example of the contribution of digital simulation. Components such as the cylinder head or piston require several iterations of testing before optimal operation can be achieved.

Due to the trend towards increasing stresses arising from operating conditions, among other considerations, the fatigue mechanism is now considered to be the main failure mode. The complexity of fatigue mechanisms has encouraged manufacturers to use modern simulation methodologies from the earliest stages of development.

For the whole of this article, an example of the recent development of a new family of internal combustion engines, and in particular its cylinder head, has been used.