Comparison of Various Critical Plane Approaches Under Proportional and Non-Proportional Multiaxial Stress States
Tuğçe Leblebici Emin Sünbüloğlu S. Ergün Bozdağ
AbstractThe investigation of the fatigue behaviour of metals under non-proportional multi-axial stress states is an important problem to minimize design-induced errors and improve structural durability, especially for cast and light-weight sheetmetal structures. Various approaches that can be used in fatigue analyses make use of stress states, strain states and strain energy densities to obtain an endurance limit value, a fracture plane estimate, S-N curve and/or a combination of these. Thus, the determination of the possible initial cracking plane and an estimation of crack initiation is an important step in fatigue analysis of structural design, especially under multiaxial stress states based on theories that are stress-based where the method of critical planes is the most commonly applied. Such methods seek for the orientation of fracture plane by using different parameters based on the assumed input parameters. The purpose of this research is to identify and compare critical plane orientations using various stress approaches to critical plane methods. The determination of several parameters in different stress based critical plane search is indicated. Furthermore, critical planes are found for different stress states with using pre-assumed material properties from available test data. Based on the outcomes, a method of better versatility and ease of application is proposed among the methods investigated for practical applications of fatigue analysis.