Dariusz Rozumek

Fatigue Characteristic of Aluminium Alloy 2024 under Cyclic Bending with the Controlled Energy Parameter

In this paper the results of fatigue tests under cyclic bending of 2024 aluminium alloy with amplitude of strain energy density parameter control are presented. Based on these tests, energy fatigue characteristic of the tested material was elaborated.

Crack Growth Path in Specimens with Rectangular Section under Bending with Torsion

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.

Crack Growth in AlCu4Mg1 Alloy under Combined Cyclic Bending and Torsion

Aluminium and its alloys are the materials tested for many years and frequently used for the elements of fatigue loading. The most characteristic properties of aluminum are low weight (3 times less than iron) and low melting point (about 2.5 times smaller than the iron). In addition, aluminum has good corrosion resistance properties by creating a thin and tight (passive) layer of Al2O3. Therefore, aluminum alloys are widely used in the construction of airplanes, vehicles, transport equipment, machinery or parts of building structures. All technical alloys are divided into two groups: alloys for plastic working and foundry alloys. The boundary between them is determined by the maximum content of an additional component dissolved in the solid solution at the eutectic temperature. The appearing eutectic adversely affects the technological properties of the alloy (reduced susceptibility to plastic working). As for aluminum alloys subjected to plastic working and heat treatment in order to their hardening, duralumin is most widely applied. These alloys are usually subjected to heat treatment consisting of annealing, saturating or ageing. In the paper (Kocanda & Kozubowski, 1974) the authors studied the influence of microstructure on the alloy PA6 on appearance of fatigue microcracks. It was noted the presence of gas microbubbles, and precipitations of secondary phases. It was found that gas microbubbles are the source of fatigue microcracks. Doring et al. (2006) presented the test results described by the ΔJ-integral range, obtained under non-proportional loading including the crack closure. The test results obtained under tension with torsion for three materials (two steels and one aluminium alloy) were analysed. Different loading paths were applied (circle, ellipse, octant, square and cross). Fatigue crack growth behavior (Chung & Yang, 2003) in Al 6061-T6 thick aluminium plate with composite material patch was studied. Five inclined crack plates repaired with patch were tested. Crack branching at the threshold level and crack closing can be described (Pokluda, 2004) with the local approach including the ratio of the grain size to the plastic zone size. At that level of the crack development there are three mixed-cracking modes before the crack front, even in the case of mode I only, visible outside the tested element. Three materials were tested (steel, aluminium alloy and titanium alloy). The aim of this chapter is the presentation of static and cyclic properties of aluminum alloy AlCu4Mg1 and to present the test results of fatigue crack growth in plane notched specimens under bending and proportional bending with torsion.

Influence of the Microstructure on the Fatigue Cracks Growth in the Joint Zirconium-Steel Made by Explosive Welding

This paper assesses the effect of various values of detonation velocity on the quality of the bond zone. The results of structural, static and fatigue studies were presented for bonds in the initial state. Depending on the applied technological settings of welding, most cases displayed a wavy bond with highly diversified parameters of the wave. High detonation velocities favoured the formation of waves with great height and length and clearly affect the increase in the volume of hard and brittle regions of melt in the bond zone. Increased volume of the melted regions in the bond zone results in the decrease of fatigue resistance and strength properties of the clads.

Fatigue Crack Growth in Specimens with Rectangular Section under Torsion and Bending with Torsion

The paper presents the test results on the fatigue crack growth under torsion and proportional bending with torsion in the aluminium alloy EN AW-2017A-T4. 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. Plane specimens with stress concentrators in form of the external one-sided blunt notch were tested. The results of experiments were described on graphs of the fatigue crack length „a” versus numbers of cycles N. A non-uniform fatigue cracks growth on both lateral surfaces of specimens was observed during experimental tests.

Numerical Analysis of Stress and Strain in Specimens with Rectangular Cross-Section Subjected to Torsion and Bending with Torsion

Abstract 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.

Energy Fatigue Characteristic of C45 Steel Subjected to Cyclic Bending

The paper contains the results of fatigue tests under cyclic bending of C45 steel with amplitude of energy parameter control. The tests were performed on the smooth specimens. Based on these tests, energy fatigue characteristic of the tested material was elaborated.

Influence of the Microstructure near the Interface on the Fatigue Life of Explosively Welded (Carbon Steel)/Zr Clads

The paper presents joint zone microstructure and the test results obtained for fatigue cracks in zirconium-steel bimetal under bending. The materials were joined with explosive welding technology, and special attention was paid to characteristics of the joint zone.

Influence of the Titanium and its Alloys Microstructure on the Fatigue Crack Paths

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.

Influence of Heat Treatment on Fatigue Crack Growth in Ti-6Al-4V Alloy

The paper contains the results of experimental work carried out in order to analyse the initiation and propagation of fatigue cracks in Ti-6Al-4V titanium alloy. The tests were performed on plane specimens with the stress concentrators in form of one-sided sharp notches. The tested specimens were made of the oxygenated Ti-6Al-4V subjected to various variants of heat treatment.