Janusz Lewandowski

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.

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.

Test of fatigue crack growth in welded specimens subjected to bending

The paper presents the test results on the fatigue crack growth under cyclic bending specimens at constant moment amplitude made of S355 steel with fillet welds. Plane specimens with stress 195 Badanie wzrostu pęknięć zmęczeniowych w spawanych próbkach poddanych zginaniu concentrators in form of the external two-sided blunt notches were tested. The tests were performed under constant value of the stress ratio R = –1 without and after heat treatment. The article also presents the test results of the microstructure of welded joints taking into account changes in the material after heat treatment and the impact of these changes on the fatigue life of specimens.

Numerical Analysis of Stress Intensity Factor in Specimens with Different Fillet Geometry Subjected to Bending

Abstract The article presents the maps of xx stress component and compares values of analytical and numerical calculations for the stress intensity factor range of welded specimens with fillet welds which subjected to cyclic bending. The tests were performed under constant value of moment amplitude Ma = 9.20 N·m and stress ratio R = σmin/ σmax = −1. The specimens were made of drag steel rod S355. The specimens were solid and welded. The numerical models were simulated with ABAQUS suite and numerical calculations performed with FRANC3D software.

Influence of Fillet Welded Joints Subjected to Cyclic Bending on Fatigue Crack Growth in S355 Steel

The paper contains the results of experimental work carried out in order to analyse the initiation and propagation of fatigue cracks in S355 steel. The tests were performed on plane specimens with the stress concentrators in form of the external two-sided blunt notches. Tests were performed on specimens with fillet welds (concave and convex) made of S355 steel, subjected to cyclic bending.

Testing of specimens with fillet welds under variable bending

The paper contains the results of experimental work carried out in order to analyse the initiation and propagation of fatigue cracks in S355 steel. Unilaterally restrained specimens were subjected to cyclic bending at the constant amplitude moment Ma = 9.20 N·m for the stress ratio R = −1, 0 and the loading frequency 28.4 Hz. The tests were performed on plane specimens with the stress concentrators in form of the external two-sided blunt notches. Tests were performed on specimens with fillet welded joint.

Metody nieniszczące w badaniach połączeń spawanych wirnika wentylatora; Non-destructive methods in the tests on welded joints of the rotor fan

W pracy zaprezentowano krotką charakterystyke metod nieniszczących uzywanych do badan polączen spawanych. Badaniom poddano wirnik wentylatora WPK 5,0 celem sprawdzenia jego przydatności do dalszej eksploatacji. Plyte czolową oraz lopaty wirnika wykonano ze stali S355. Podczas badan metodą magnetyczno-proszkową wykryto pekniecia w niektorych zlączach spawanych wirnika. Po naprawie pekniec dokonano ponownie badan nieniszczących metodą ultradźwiekową nie stwierdzając dalszych uszkodzen wirnika. Abstract The paper presents a brief description of the methods used for nondestructive testing of welded joints. Rotor fan type WPK 5.0 was examined to verify its suitability for continued service. The front plate and the rotor blades are made of steel S355. During the test cracks by magnetic-particle were detected in some of the welded joints of the rotor. non-destructive testing (ultrasonic method) was repeated after repairing cracks. This did not confirm further damage to the rotor.