Casting and additive manufacturing enable the exact design of complex interior and external shapes and hardness that are tailored to the local load flow of an application (AM). Aluminum silicon alloys are frequently utilized in the transportation industry because of their excellent casting properties and low density. These alloys are particularly well-liked in the rail and automotive industries. Find out more about how to calculate fatigue life.
It is only possible to partially eradicate errors brought on by the manufacturing process, despite the most recent developments in casting and additive manufacturing. Because of this, whenever strongly loaded parts are being designed, process-induced failures need to be carefully taken into account. The conventional adjustment for light metal alloys is one of a number of methods that can be used to describe how flaws affect fatigue strength.
What does Research Say?
In this report, the potential for creating a standard damage tolerance evaluation to guarantee the dependability of mechanical systems with defects and mechanical systems under fatigue loads is explored.
Fault lifetime curves were produced using the linear-elastic fracture mechanical (LEFM) method. The failure-initiating defect’s (area) cyclic stress intensity factor (K) was used to describe the local stress concentration conditions in place of nominal stress-based S-N curves. In place of the nominal stress, this was done.
When creating J-based K-N curves, the researchers modified the LEFM method using CSS behavior by employing Jeff, a real-world cyclic J integral. The new data needed to be accommodated, so this was done.
On the behavior of fatigue and fatigue damage-tolerant (FDT) materials made of cast and additively manufactured Al-Si, the effects of process-induced microstructure, defects, porosity, and stress-strain behavior were examined.
The AlSi10Mg material was created using the powder bed fusion with a laser beam (PBF/LB) technique, as opposed to the cast AlSi7Mg materials, which were created using the sand casting and die casting processes. The cast materials underwent modifications in terms of porosity, eutectic Si precipitates, dendritic arm spacing, and cooling rate, while the AM material was assessed in its initial form. Tensile tests and incremental step tests, respectively, were performed in order to identify the quasi-static (QSS) and CSS characteristics.
The J integral to stress intensity factor (SIF) dimension, which is used in the J-based Shiozawa diagram, was explained in this study using Kj-N curves. This dimension is also known as the Kj dimension or the J-SIF dimension. Regardless of the material’s microstructure, plasticity, or porosity, evaluations of FDT can now be carried out with reliability and accuracy. It is possible to create a uniform FDT law, as well as an FDT limit or fatigue limit, for the HCF regime. This would be advantageous.