Rotating Bending Fatigue Tests Research Articles

Fatigue Test of Plastics and Manufacturing Collet Nut Driver for Integrated Rotating Bending Fatigue Test Machine

The unknown fatigue life of injection molded plastic materials and the ineffectiveness of clamping both ends of the specimen in the collet of the Integrated Rotary Bending Fatigue Testing Machine with manual tightening and loosening are the obstacles faced. The purpose of testing and making a collet nut driver is to obtain a prediction of the fatigue life of injection molded plastic materials and to increase the effectiveness of clamping the end of the specimen with the help of a DC motor drive. The research method uses experiments which include injection molding of plastic materials of the type Polypropylene (PP) and Acrylonitrile Butadiene Styrene (ABS), checking the straightness and surface finishing of the specimen, fatigue testing at 1800, 2000, 2200 rpm, analysis of fatigue test results, and design-manufacturing collet nut drive with DC motor drive and transmission of a pair of spiral cone gears, manufacture of DC motor sliding movement mechanism along the reach of both ends of the specimen, installation of electric power circuits for direction and electric current switches for clockwise and counterclockwise rotation functions, and analysis of the results of the fatigue test and performance of the collet nut driver The results of fatigue testing at a bending stress (S) of 68 MPa for PP material show that at 1800 rpm, the fatigue life (N) was obtained at 2,014,605 cycles and at 2200 rpm, N was obtained at 1,506,486 cycles. Meanwhile, for ABS specimens, at 1800 rpm, N was obtained at 1,547,106 cycles and at 2200 rpm, N was obtained at 1,190,425 cycles, which means PP material has a longer fatigue life compared to ABS. The test results of the DC motor drive on the collet nut showed that the duration of tightening/loosening was 4.4 times faster than manually, which originally had a duration of 66 seconds, down to just 15 seconds for the DC motor drive.

A Time‐Saving Method for Evaluating the Fatigue Strength of Carburized High‐Alloy Steel Containing Carbides

To propose a time‐saving method for evaluating the fatigue strength of carburized steel, the fatigue behavior and fracture mechanism of carburized 14Cr14Co13Mo5 steels are studied by the rotary bending fatigue tests. It is found that the fatigue crack initiation site changes from surface to internal after carburizing due to the residual compressive stress and carbide cluster caused by the carburization. Besides, a notable correlation between the stress intensity of the cracked carbides at fatigue crack initiation site and fatigue life is observed in the carburized samples. This correlation allows for the estimation of fatigue strength at long conditional life based on samples tested at relatively high stress amplitudes with short lives, achieving a prediction error within 10% for the material studied. A significant time saving of ≈65% compared to the staircase method is achieved. The proposed method has significant implications for improving the efficiency fatigue strength evaluation in carburized steels containing carbides.

Bending moment calibration for rotational bending fatigue testing machine based on strain measurement

Abstract Rotational bending fatigue testing is an important method to evaluate the fatigue of metal materials under cyclic loading. Specifically, the fatigue strength is evaluated through repeated rotational bending under complex loads with the accuracy affected by the bending moment. Here, a method based on strain measurements is proposed for calibrating the bending moment of rotational bending fatigue testing machines. Specifically, the strain of a metal sample under loading with resistance strain gauges was recorded using a strain acquisition system to measure the bending moment. The positions of strain gauges were designed according to the principle of strain measurements to establish a calibration program. Three metal samples of different sizes were tested on two types of rotational bending fatigue testing machines, and the measurement uncertainty was evaluated and verified. The experimental results showed that the proposed method measured and calibrated the bending moment of rotational bending fatigue testing machines rapidly, conveniently, and accurately. The results also provide a practical reference for research and application in related fields.

Rotating Bending Fatigue Durability of Wrought 304 Stainless Steel: A Comparative Study of Surface-Treated vs. Untreated Specimen

The rotating bending fatigue test, which is a common durability test for industrial components, was employed in this study to examine the impact of the surface treatment procedure on the material's performance under room temperature. The studied material in this research is a wrought stainless steel (SS) 304 alloy that has undergone a specialized surface treatment to enhance the fatigue properties of this unique material. The fatigue endurance of untreated materials was 405 MPa (65% of untreated specimen’s yield strength) on 5 million runout cycles, while the surface-treated samples exhibited 545 MPa (85% of treated specimen’s yield strength), a significantly greater value compared to the untreated ones (even up to 10 million runout cycles). The experimental results demonstrated that the surface-treated samples exhibited no signs of cracking. Instead, all failures were attributed to plastic bending, particularly at higher stress levels. Furthermore, the samples displayed a limited range of stress levels, spanning from endurance to plastic bending conditions. This finding suggests that the hypothesis of an increase in stiffness in the surface layer is more pronounced than in the material interior. It also indicates that the surface layer material was not cracked under the maximum stress level, while the layer beneath it experienced plastic deformation. A comparison has been made between the Basquin equation and a statistical machine learning model (for a limited amount of data) to incorporate the impact of surface treatment on predicting fatigue lifetime, and the random forest regressor model would be able to predict the lifetime with the accuracy of R2= 87% which was much higher than the classical model.

Prediction of rotational bending fatigue life of bearing steel based on damage mechanics

Based on the theory of continuous damage mechanics, this paper proposes a fatigue damage evolution model and numerical calculation method considering the influence of vacuum chemical heat treatment process, and studies the rotational bending fatigue damage analysis and life prediction method of M50NiL bearing steel. Firstly, the constitutive model, fatigue damage evolution equation and material parameter calibration method in the theoretical model are given. Secondly, based on the ABAQUS platform, the damage mechanics-finite element numerical calculation method of fatigue damage analysis considering the influence of hardened layer is realized by writing the UMAT subroutine; then, the rotational bending fatigue test of M50NiL bearing steel treated by vacuum chemical heat treatment of quenching and tempering, carburizing and carbonitriding is carried out, and the influence of heat treatment process on fatigue performance is analyzed; finally, based on the proposed fatigue damage model and numerical calculation method, the rotational bending fatigue life of M50NiL bearing steel is predicted, and the results are compared with the experimental results to verify the correctness of the proposed method.

Prediction of rotational bending fatigue life of bearing steel based on damage mechanics

Based on the theory of continuous damage mechanics, this paper proposes a fatigue damage evolution model and numerical calculation method considering the influence of vacuum chemical heat treatment process, and studies the rotational bending fatigue damage analysis and life prediction method of M50NiL bearing steel. Firstly, the constitutive model, fatigue damage evolution equation and material parameter calibration method in the theoretical model are given. Secondly, based on the ABAQUS platform, the damage mechanics-finite element numerical calculation method of fatigue damage analysis considering the influence of hardened layer is realized by writing the UMAT subroutine; then, the rotational bending fatigue test of M50NiL bearing steel treated by vacuum chemical heat treatment of quenching and tempering, carburizing and carbonitriding is carried out, and the influence of heat treatment process on fatigue performance is analyzed; finally, based on the proposed fatigue damage model and numerical calculation method, the rotational bending fatigue life of M50NiL bearing steel is predicted, and the results are compared with the experimental results to verify the correctness of the proposed method.

Improvement of fatigue life by aluminizing of additive manufactured Fe- and Ni-base alloy

Improvement of fatigue life by aluminizing of additive manufactured Fe- and Ni-base alloy

Impact of biological environment on bending fatigue lifetime in additive-manufactured polylactic acid fabricated by 3D-printing

Impact of biological environment on bending fatigue lifetime in additive-manufactured polylactic acid fabricated by 3D-printing

Development of new AlSi-alloys reinforced with titanium-based particles for laser powder bed fusion: tension and rotary bending fatigue tests

Development of new AlSi-alloys reinforced with titanium-based particles for laser powder bed fusion: tension and rotary bending fatigue tests

Effect of peening with fine iron-sulfide particles on the rotating bending fatigue properties of low alloy steel and formation of iron-sulfide layer

Effect of peening with fine iron-sulfide particles on the rotating bending fatigue properties of low alloy steel and formation of iron-sulfide layer

Influence of Inclusion Parameter and Depth on the Rotating Bending Fatigue Behavior of Bearing Steel

Inclusions are an important parameter affecting the fatigue life of materials. In this paper, the type, size, and quantity of inclusions in bearing steel were quantitatively analyzed using scanning electron microscopy and automatic scanning electron microscopy with an X-ray energy dispersive spectroscopy function. The effects of the inclusion parameters and positions on the rotating bending fatigue properties were analyzed using the rotating bending fatigue test. The results proved that for samples 1 and 2, the inclusions were mainly sulfides, Ti-containing inclusions, and their composite inclusions. For samples 3 and 4, the inclusions were mainly oxides or sulfide–oxide complexes. The number and maximum size of inclusions in sample 2 were relatively small. This was mainly due to the difference in the content of Al, S, and Ca elements in the different samples. The inclusion distance to the surface and the maximum inclusion size had a larger influence on the rotating bending fatigue life in comparison to the inclusion type. Moreover, nitride–oxides had a more detrimental effect on the rotating bending fatigue life as compared to the sulfide–oxide complex inclusions. A model was established on the basis of the inclusion size, depth, and stress by using the Python software. The simulation demonstrated that using five parameters fit well with the experiment results.

Fatigue crack extension mechanism and mode-type analyses of martensitic steels for proposing fatigue strength evaluation method: Example of 18% Ni BCC martensitic steel

Fatigue crack extension mechanism and mode-type analyses of martensitic steels for proposing fatigue strength evaluation method: Example of 18% Ni BCC martensitic steel

Synergistic impact of corrosion pitting on the rotating bending fatigue of additively manufactured 316L stainless steel: Integrated experimental and modeling analyses

Synergistic impact of corrosion pitting on the rotating bending fatigue of additively manufactured 316L stainless steel: Integrated experimental and modeling analyses

Enhancing high cycle fatigue performance of plasma nitrided AISI 4140 steel by post-aging treatment and direct current magnetic field

Enhancing high cycle fatigue performance of plasma nitrided AISI 4140 steel by post-aging treatment and direct current magnetic field

Fatigue performance testing and life prediction of welded fuel pipes

Fatigue performance testing and life prediction of welded fuel pipes

Abnormal fatigue behavior of a CoCrW-based wear-resistant alloy

Abnormal fatigue behavior of a CoCrW-based wear-resistant alloy

Design and manufacturing of rotating bending fatigue test machine

Design and manufacturing of rotating bending fatigue test machine

A novel machine learning-based model for predicting the transition fatigue lifetime in piston aluminum alloys

A novel machine learning-based model for predicting the transition fatigue lifetime in piston aluminum alloys

A comprehensive study on the effects of surface post-processing on fatigue performance of additively manufactured AlSi10Mg: An augmented machine learning perspective on experimental observations

A comprehensive study on the effects of surface post-processing on fatigue performance of additively manufactured AlSi10Mg: An augmented machine learning perspective on experimental observations

Complex-inclusion induced fracture mechanism of ultraclean 100Cr6 bearing steel under high cycle fatigue test

Complex-inclusion induced fracture mechanism of ultraclean 100Cr6 bearing steel under high cycle fatigue test