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We present experimental results on the fatigue crack growth in specimens with rectangular cross sections made of 2017A-T4 aluminum alloy under bending. The specimens were weakened by sharp and blunt one-sided notches (for the notch root ρ = 0.2; 5; 10 and 22.5 mm). The tests were performed on a MZGS-100 fatigue test bench in the low- and high-cycle fatigue modes by imposing a constant value of the nominal load ratio R = – 1; 0 and a moment amplitude M a = 15.84 N·m. The results of fatigue tests were then analyzed in terms of the parameter ΔK including the influence of the notch.

This paper presents an analysis of the state of fatigue fracture surface in specimens with rectangular cross-section. The specimens were made of EN AW-2017A-T4 aluminium alloy and had an external, unilateral, sharp and blunt one-sided notches, with the of radius ρ = 0.2 mm, 5 mm, 10 mm and 22.5 mm. Fatigue test subjected to bending, torsion, and proportional bending with torsion for stress ratio R = −1, −0.5, 0 were carried.

The paper presents the test results on the fatigue crack growth under bending, torsion and proportional bending with torsion. The tests were performed at the fatigue test stand MZGS-100 at the constant amplitude of moment MB = MT = MBT = 15.84 N⋅m and stress ratio R = -1. Specimens with rectangular cross-section in fatigue tests were used and were made of EN AW-2017A aluminium alloy. The EN AW-2017A alloy consists of α grains and the Al2Cu phase. The effect of the microstructure on the crack paths in specimens was observed. Transcrystalline cracks through grains of the α phase have been usually observed on the fractures.

The paper presents an analysis of the state of stress and crack tip opening displacement (strain) in specimens with rectangular cross-section subjected to torsion and combined bending with torsion. The specimens were made of the EN AW-2017A aluminium alloy. The specimens had an external unilateral notch, which was 2 mm deep and its radius was 22.5 mm. The tests were performed at constant moment amplitude MT = MBT = 15.84 N·m and under stress ratio R = −1. The exemplary results of numerical computations being obtained by using the FRANC3D software were shown in the form of stress and crack tip opening displacement (CTOD) maps. The paper presents the differences of fatigue cracks growth under torsion and bending with torsion being derived by using the FRANC3D software.

The work deals with the tests results of the growth of fatigue cracks subjected to torsion and bending with torsion specimens at the constant amplitude loading and with zero or non-zero mean load. In the fatigue tests, specimens made of AW-2017A-T4 alloy with rectangular cross-section weakened by external notches were used. The results of experimental and numerical calculations were presented. During experimental investigations, heterogeneous growth of fatigue cracks at the front and rear of the specimen was noticed. Thereby, both the crack growth rate and the cracking process itself are affected. Two types of fatigue cracking were also observed: surface and passing through specimen. Crack paths were measured on the surface of the specimens using a microscope. Different lifetimes were observed for the specimens subjected only to cyclic torsion compared to those subjected to bending with torsion in the first and second periods of cracking. At the final stage of cracking, both in bending with torsion and in torsion, the difference in crack lengths for ratio a/c and a/a* is greater for R = −1 than for R = 0.

The paper presents the results of tests on the fatigue crack growth rate for a constant moment amplitude under combined bending with torsion in the aluminium alloy AlCuMg1. The tests were performed under different values of the stress ratio R. Plane specimens with stress concentrators in form of the external one-sided sharp notch were tested. The results of experiments were described on graphs of the fatigue crack growth rate versus changes of the stress intensity factor range ΔK. A non-uniform fatigue cracks growth on both lateral surfaces of specimens was observed during experimental tests.

The paper presents the results of tests on the fatigue crack growth for a constant moment amplitude under combined bending with torsion in the aluminium alloy AW-2017A-T4. The tests were performed under different values of the load ratio R. Plane specimens with stress concentrators in form of the external one-sided sharp notch were tested. A non-uniform fatigue cracks growth on both lateral surfaces of specimens was observed during experimental tests. Fatigue cracks were developing in the specimens in two stages; quarter-elliptic edge cracks were observed at the beginning, then evolving into through cracks.

The paper contains the results of tests on the fatigue crack growth in titanium Gr.1 and Ti-6Al-4V as well as Ti-3Cu titanium alloys. The chosen materials contained titanium but their structure was different. Plane specimens with the stress concentrators in form of one-sided sharp notches were tested. Influence of the microstructure on the crack paths in plane specimens was observed.