Influence of mean stress and stress amplitude on uniaxial and biaxial ratcheting of ST52 steel and its prediction by the AbdelKarim–Ohno model

Halama, Radim; Fusek, Martin; Poruba, Zdeněk

doi:10.1016/j.ijfatigue.2016.04.033

Cited by 38 publications

(29 citation statements)

References 14 publications

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“…21 In recent years, several plasticity models and the empirical formulations are used to evaluate mean stress relaxation. 24,[29][30][31][32] Also, some logarithmic and exponential empirical models 12,33 have been developed based on the experimental results which are convenient for simulating and predicting the stress relaxation. 24,[29][30][31][32] Also, some logarithmic and exponential empirical models 12,33 have been developed based on the experimental results which are convenient for simulating and predicting the stress relaxation.…”

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confidence: 99%

Experimental and numerical analyses of mean stress relaxation in cold expanded plate of Al‐alloy 2024‐T3 in double shear lap joints

Abdollahi

Chakherlou

2018

Fatigue Fract Eng Mat Struct

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In this paper, the mean stress relaxation behavior of simple Al‐alloy 2024‐T3 specimens and also the mean stress relaxation around the hole of cold expanded specimen are studied. The analyses are performed through the combination of the nonlinear isotropic hardening and Chaboche nonlinear kinematic hardening model accompanied by the results of experimental tests. The strain‐controlled axial tests are performed at two different strain amplitudes, while the stress‐controlled tests of cold expanded specimens are performed for three different imposed load amplitudes. The constitutive equations of the hardening model are coded as a UMAT subroutine in FORTRAN programming language and implemented in the commercial finite element code of ABAQUS. The accuracy of the hardening model has been proved in two steps: first by simulations of mean stress relaxation during the uniaxial strain‐controlled cyclic tests and second by simulation of strain ratcheting during the stress‐controlled cyclic loading. The stress and strain distributions after cold expansion process are examined as well as the mean stress relaxation due to cyclic loading. The results show the influences of imposed stress amplitude on increasing mean stress relaxation and also the effect of cold expansion level on reducing the mean stress relaxation.

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confidence: 99%

Experimental and numerical analyses of mean stress relaxation in cold expanded plate of Al‐alloy 2024‐T3 in double shear lap joints

Abdollahi

Chakherlou

2018

Fatigue Fract Eng Mat Struct

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“…It is clear from the presented results that MCH4 + NLISO model predicts the experimental results better in comparison with CH3 + NLISO model. Also, the comparison of the accumulated strain between two states of loading (L1 and L2) shows that at the same applied stress amplitude, increasing the mean stress increases the strain ratcheting . Also, the results of uniaxial stress‐strain curve obtained from the experimental tests along with simulation results from MCH4 + NLISO model for L1 loading condition during the first cycle of loading and the 5th, 20th, 50th, and 150th cycle are presented in Figure .…”

Section: Finite Element Model Results and Discussionmentioning

confidence: 98%

“…The amplitude of applied load should be in the range that could induce stresses less than the ultimate strength and higher than the yield strength of the material. The effect of loading frequency on the ratcheting was studied, and in the frequency range between 0.1 and 1 Hz, the ratcheting rate was insensitive to the magnitude of loading frequency . In this category of the tests, also, the antibuckling guides were used, and because of presence of them as shown in Figure A, it was not possible to position the strain gauges at the plate surface, and it was attached laterally again.…”

Section: Experimental Studiesmentioning

confidence: 99%

Numerical and experimental study of ratcheting in cold expanded plate ofAl‐alloy 2024‐T3 in double shear lap joints

Abdollahi

Chakherlou

2017

Fatigue Fract Eng Mat Struct

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In this paper strain ratcheting in cold expanded flat plate of Al-alloy 2024-T3 in double shear lap joints was studied both experimentally and numerically. In the experimental part, two types of symmetric strain-controlled and asymmetric stress-controlled cyclic tests were performed. Also, the cold expanded double shear lap joints subjected to cyclic stress-controlled tests. The required parameters for simulating the cyclic plastic behaviour of Al-alloy 2024-T3 were obtained on the basis of the experimental responses. In the numerical part, a combination of nonlinear isotropic and nonlinear kinematic hardening model (Chaboche) was implemented in the commercial finite element code of ABAQUS, using the subroutine UMAT written in FORTRAN. The results of simulations give an accurate prediction of ratcheting for all types of loading. The obtained results show that increasing the mean stress increases the strain ratcheting. It is clearly shown that the cold expansion process decreases the magnitude of strain ratcheting remarkably compared with "as drilled" specimens and the decrease is bigger for larger cold expansion sizes.Also, it is shown that the middle plane has the highest amount of ratcheting compared to the pin entrance plane and exit plane of the plate hole.

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“…The entire set consisting from all three types of wavenumbers can be for given material parameters and frequency range with reasonable division obtained within 20 seconds. Currently, authors are working on development of more time-efficient algorithm in order to apply the results with cooperation of Lamb wave structural health monitoring for various experiments [11][12][13][14][15][16] and also for further application in case of composite structures [17]. …”

Section: Resultsmentioning

confidence: 99%

Numerical solution of Rayleigh-Lamb frequency equation for real, imaginary and complex wavenumbers

2018

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Abstract. Guided waves, especially Lamb waves or shear-horizontal waves, are widely used types of waves for ultrasonic inspection of large structures. Well known property of guided waves is their dispersive character, which means that the propagation velocity of the particular wave mode is not only a function of physical properties of the material, in which the wave propagates or the wave´s frequency, but also depends on the geometry of the structure in itself. Dispersion curves provide us the information related to the dependency between the wavenumber and the frequency of the particular mode and can be obtained by a numerical solution of Rayleigh-Lamb frequency equation. A solution of Rayleigh-Lamb frequency equation forms for a given frequency and plate thickness a set of a finite number of real and pure imaginary wavenumbers and an infinite number of complex wavenumbers. Proposed paper presents a complete procedure of how to obtain all three kinds of wavenumbers for a given geometry and frequency interval. The main emphasis is placed on the effectiveness of the procedures, which are used for finding the roots of dispersion equation for all three kinds of wavenumbers.

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Influence of mean stress and stress amplitude on uniaxial and biaxial ratcheting of ST52 steel and its prediction by the AbdelKarim–Ohno model

Cited by 38 publications

References 14 publications

Experimental and numerical analyses of mean stress relaxation in cold expanded plate of Al‐alloy 2024‐T3 in double shear lap joints

Experimental and numerical analyses of mean stress relaxation in cold expanded plate of Al‐alloy 2024‐T3 in double shear lap joints

Numerical and experimental study of ratcheting in cold expanded plate ofAl‐alloy 2024‐T3 in double shear lap joints

Numerical solution of Rayleigh-Lamb frequency equation for real, imaginary and complex wavenumbers

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