Fatigue life estimation for 2017A-T4 and 6082-T6 aluminium alloys subjected to bending-torsion with mean stress

Fatigue life estimation for selected materials in multiaxial stress states with mean stress

“…Experimental tests have been performed on 2017A-T4 (Kluger andŁagoda, 2013, 2014;Kluger, 2015) and 6082-T6 aluminium alloys (Niesłony et al, 2014;Kluger, 2015), S355J0 alloy steel (Pawliczek, 2000) and Ti-6Al-4V titanium alloy (Krgo et al, 2000;Kallmyer et al, 2001). The strength and fatigue properties of tested materials are listed in Table 1.…”

“…By analysing the stress condition for pure torsion and pure bending at constant--amplitude load conditions, a relationship is formulated which describes important factors for the combination of individual components. The coefficients can be presented as follows (Kluger, 2015;Łagoda and Ogonowski, 2005)…”

“…In the papers (Krgo et al, 2000;Kallmyer et al, 2001) on experimental tests related to the Ti-6Al-4V titanium alloy, it was proven that the mean torsion stress leads to a reduced fatigue life in comparison to symmetric loads. During the experimental tests of 2017(A)-T4 aluminium alloy (Kluger andŁagoda, 2013, 2014;Kluger, 2015) the effect of mean torsion stress on fatigue life was discovered. It must be noted that not all materials exhibit sensitivityto the mean torsion stress (e.g.…”

Modification of the algorithm for calculating fatigue life for the criteria based on the concept of the critical plane

“…Among many functions suggested, one group features the assumption that the components of the stress state are responsible for fatigue crack initiation associated with the plane at a specified orientation. This suggestion, called the concept of the critical plane, has attracted a lot of attention (Karolczuk and Macha, 2005a,b;Skibicki, 2007; Skibicki and Pejkowski, 2012; Kluger and Łagoda, 2014; Kluger, 2015). The reduction functions, suggested in the criteria, are used to calculate the fatigue life by comparison of the reduced value of stress σ eq to stress σ(N f ) from a fatigue curve (e.g.…”

Identification of Fatigue Cracks on the Basis of Measurable Changes in System Dynamics

“…Among other parameters, the following reduce strength properties of materials due to the occurrence of damage in material structure during service: component shape, material type, load type and the state of stress. Due to multi-aspect nature of material fatigue phenomenon and considering continuously expanding level of knowledge in this regard, individual aspects of this phenomenon are currently under thorough investigation, including: the impact of load type [4], [5], cumulation of damage during random loads [6], [7], reduction of multiaxial state of stress to an equivalent uniaxial state of stress [8], [9], or else the impact of an average value of load [10], [11]. Are also known in the literature approaches which takes into account the grain structure and the content of respective alloying elements for the purpose of estimating the fatigue life [12].…”