A FEM model for lifetime prediction of Ancorsteel1000C in rolling contact fatigue

Ancorsteel1000C is commonly used for important components including bearing rollers, gears, connecting rods, wheels and rails; most failures of these components are caused by rolling contact fatigue (RCF). In this study the fatigue damage indicator based on Fatemi-Socie critical plane were determined in a local hot spot area in finite element (FE) model in case of Hertzian stress with zero slip condition. The simulation results compared with respect to experimental data, which is in good agreement. Therefore, this approach can be implemented as a useful tool for lifetime calculations in RCF in the process of structure fatigue design. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Generation of random processes for fatigue testing

In fatigue testing there is a need to generate multivariate random processes meeting certain conditions on distributions, crossing properties and regularity. In this paper it is demonstrated how these conditions can be satisfied. The required process is generated by a random time deformation working on a Gaussian process.     

Stochastic structural analysis and lifetime oriented optimization

A stochastic structural anal sis for lifetime oriented ontimization is presented. The covariance analysis and a shaping filter-realized with singular value decomposition -enables a simultaneous formulation of load process and structure in an overall state space equation. A numerical example - industrial structure and wind load-illustrates the efficiency of the algorithm to estimate the probability density of stress ranges. The algorithm is used in lifetime oriented structural optimization     

Investigation of the dynamic fatigue of composite polymer materials

The dynamic fatigue of composite film materials has been studied as a function of the frequency and amplitude of deformation. The tests were carried out on a vibration apparatus with a frequency range from 10 to 600 cps. The test objects consisted of foil packaging with a polyethylene backing (foil-film).The dependence of the dynamic fatigue of foil-film on amplitude, frequency, and acceleration was studied. It has been shown that in all cases failure of the material is preceded by cracking of the foil and peeling of the foil from the polyethylene backing at the site of the cracks. The material fails as a result of puncture of the polyethylene backing by the broken edge of the cracked foil.Mekhanika Polimerov, Vol. 1, No. 5, pp. 90–94, 1965     

A mathematical model for lifetime prediction of lacquer-paint coatings in sea water

Main features of the mechanism of lacquer-paint coatings destruction in sea water have been revealed. On this basis, a mathematical model has been developed and boundary value problems of mathematical physics have been formulated to calculate the determining processes on characteristic stages of coatings in sea water. The theoretical evaluation of coatings longevity depending on physical characteristics of the system has been made. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Estimating the parameters of fatigue curve of a composite material

By using the method of maximum likelihood, the parameters of two versions of a mathematical model for fatigue damage accumulation in a laminate are estimated. The models, which are founded on the Markov chain theory, are very simple: they do not take into account the specific structural features of a composite and therefore cannot provide numerical coincidence with experimental fatigue test data, but they can be used for a nonlinear regression analysis of fatigue curves. A simple method is offered for approximately estimating model parameters, some of which characterize the distribution of the local static strength. By using such models, we can predict the relative changes in fatigue curves from known relative variations in the parameters of static strength and also predict the distribution function of fatigue life in program fatigue tests.Translated from Mekhanika Kompozitnykh Materialov, Vol. 41, No. 1, pp. 109–120, January–February, 2005.     

Damage modelling and lifetime prediction of adhesively bonded joints under sustained loading with constant and variable amplitudes

The lifetime of adhesively bonded joints under service loading is predicted by a linear viscoelastic traction–separation model, which is enhanced by an isotropic damage approach. Therefore, a scalar damage variable is defined according to the concept of effective stresses based on the hypothesis of strain equivalence in the framework of continuum damage mechanics. The damage evolution is driven by a specific equivalent stress, adapted for ductile adhesives. Experimental data acknowledge the validity of the proposed model for the lifetime prediction of adhesive joints. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

A generalized model for static fatigue lifetime evaluation of optical fibers to reduce the model uncertainty

The mechanical reliability of silica-based optical fibers declines especially under the combination of applied stresses and severe chemical environment in service. It is of great concern to assess the mechanical reliability and lifetime based on the short-term accelerate testing and the relevant mechanism. The long-term lifetime prediction of optical fibers is sensitive to the form of kinetic model, yet no fair and common agreement has been reached on the best model. This study proposes a generalized lifetime model to search the best model in an expanded model space and hence can reduce model uncertainty. Following that, a procedure using the maximum likelihood estimation and the likelihood ratio test is conducted to determine the model structure. Furthermore, three sets of static fatigue lifetime data are used to illustrate the validity and superiority of the proposed framework. The result demonstrates that the proposed framework can reduce the uncertainty in model choice and is readily applicable to evaluation of static fatigue lifetime of optical fibers.