A Study of Fatigue-Life Estimation and Reliability Analysis for Dental Implants

2012 ◽  
Author(s):  
Yuo-Tern Tsai ◽  
Y. K. Lu ◽  
Y. Y. Hsu ◽  
J. B. Lu
Keyword(s):  
Experimental Data ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Dental Implants ◽  
Fatigue Testing ◽  
Simulation Analysis ◽  
Linear Regression Method ◽  
Estimation Model ◽  
Life Estimation ◽  
Fatigue Life Estimation

Recently, dental implants (DIs) are extensively utilized on edentulous patients. The bio-compatibility & physical properties of DIs are severely specified since it belongs to the products of biomedicine. Generally, DIs must pass a series of tests before they are approved to use in human body. In this paper, a method of probabilistic fatigue-life estimation was proposed to fulfill reliability life prediction of DIs. The probabilistic form of fatigue-life evaluation is developed based on material constants namely fatigue strength coefficient and fatigue strength exponent. The procedure is developed based on the shift of the fatigue-life curve to the desired value of the probability of occurrence. This estimation model yields the life distribution in respect of the scatter of the cyclic properties of DIs. The CAD models of DIs are first constructed to perform computer simulation analysis for establishing the fracture spots. The stress analysis and life estimation were carried out by ANSYS software. The simulation results are further compared with the experimental data obtained by fatigue testing to determine the estimated model of fatigue life. The parameters of the model were determined by linear regression method based on the combination of the simulated and experimental data. The reliabilities of DIs were further investigated to provide an index of life-safety of DI at different cyclic loads. The analyzed results may be useful while programming the fatigue testing of DIs.

Fatigue life and reliability evaluation for dental implants based on computer simulation and limited test data

2012 ◽  
Vol 227 (3) ◽  
pp. 554-564 ◽  
Author(s):  
Yuo-Tern Tsai ◽  
Kuo-Shong Wang ◽  
Jeng-Chung Woo
Keyword(s):  
Computer Simulation ◽  
Fatigue Life ◽  
Dental Implants ◽  
Test Data ◽  
Regression Line ◽  
Preliminary Investigation ◽  
Estimation Model ◽  
Life Estimation ◽  
Fatigue Life Estimation ◽  
Edentulous Patients

Dental implants have been extensively utilized on edentulous patients for many years. The fatigue life of dental implants is critical for them being approved to use in human body because they are within the area of biomedicine. To perform a preliminary investigation of fatigue life of dental implants, this article reports a method of fatigue life estimation based on the combination of computer simulation and limited test data. The method is developed based on a probabilistic form of fatigue life given according to the properties of material fatigue strength. The procedure is carried out by shifting of the regression line (representing the fatigue–life curve) to the desired value of the probability of occurrence. Computer simulation includes both stress analysis and life estimation which are done using the ANSYS software. This estimation model offers a method for fatigue life evaluation and yields the life distribution in respect to the scatter of the cyclic properties of dental implants. Furthermore, the reliability of lifetime is calculated based on the probabilistic form. The purposes of this study are to predict fatigue life using a small amount of testing data and to provide a risk assessment for dental implants in use.

Fatigue life estimation in dental implants

2014 ◽  
Vol 123 ◽  
pp. 34-43 ◽  
Author(s):  
J.M. Ayllón ◽  
C. Navarro ◽  
J. Vázquez ◽  
J. Domínguez
Keyword(s):  
Fatigue Life ◽  
Dental Implants ◽  
Life Estimation ◽  
Fatigue Life Estimation

scholarly journals Application of the S-N Curve Mean Stress Correction Model in Terms of Fatigue Life Estimation for Random Torsional Loading for Selected Aluminum Alloys

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2985
Author(s):  
Michał Böhm ◽  
Krzysztof Kluger ◽  
Sławomir Pochwała ◽  
Mariusz Kupina
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Stress Effect ◽  
Mean Stress ◽  
Torsional Loading ◽  
Correction Model ◽  
Life Estimation ◽  
Mean Stress Effect ◽  
Fatigue Life Estimation ◽  
The Mean

The paper presents the experimental fatigue test results for cyclic constant amplitude loading conditions for the case of the torsion of the PA4 (AW-6082-T6), PA6 (AW-2017A-T4) and PA7 (AW-2024-T3) aluminum alloy for a drilled diabolo type test specimen. The tests have been performed for the stress asymmetry ratios R = −1, R = −0.7, R = −0.5 and R = −0.3. The experimental results have been used in the process of a fatigue life estimation performed for a random generated narrowband stress signal with a zero and a non-zero global mean stress value. The calculations have been performed within the time domain with the use of the rainflow cycle counting method and the Palmgren−Miner damage hypothesis. The mean stress compensation has been performed with the S-N curve mean stress model proposed by Niesłony and Böhm. The model has been modified in terms of torsional loading conditions. In order to obtain an appropriate R = 0 ratio S-N curve fatigue strength amplitude, the Smith−Watson−Topper model was used and compared with literature fatigue strength amplitudes. The presented solution extends the use of the correction model in terms of the torsional loading condition in order to obtain new S-N curves for other R values on the basis of the R = −1 results. The work includes the computational results for new fatigue curves with and without the mean stress effect correction. The results of the computations show that the mean stress effect plays a major role in the fatigue life assessment of the tested aluminum alloys and that the method can be used to assess the fatigue life under random conditions.

Fatigue Laws via Functional Equations

2008 ◽  
Author(s):  
Navendu Patil ◽  
Pradeep Mahadevan ◽  
Anindya Chatterjee
Keyword(s):  
Experimental Data ◽  
Fatigue Life ◽  
Ad Hoc ◽  
Complex Loading ◽  
Metal Fatigue ◽  
Life Estimation ◽  
Fatigue Life Estimation ◽  
Miner’S Rule ◽  
Miner's Rule ◽  
Many Sources

In routine industrial design, fatigue life estimation is largely based on S-N curves and ad hoc cycle counting algorithms used with Miner’s rule for predicting life under complex loading. However, there are well known deficiencies of the conventional approach. Of the many cumulative damage rules that have been proposed, Manson’s Double Linear Damage Rule (DLDR) has been the most successful. Here we follow up, through comparisons with experimental data from many sources, on a new approach to empirical fatigue life estimation (‘A Constructive Empirical Theory for Metal Fatigue Under Block Cyclic Loading’, Proceedings of the Royal Society A, in press). The basic modeling approach is first described: it depends on enforcing mathematical consistency between predictions of simple empirical models that include indeterminate functional forms, and published fatigue data from handbooks. This consistency is enforced through setting up and (with luck) solving a functional equation with three independent variables and six unknown functions. The model, after eliminating or identifying various parameters, retains three fitted parameters; for the experimental data available, one of these may be set to zero. On comparison against data from several different sources, with two fitted parameters, we find that our model works about as well as the DLDR and much better than Miner’s rule. We finally discuss some ways in which the model might be used, beyond the scope of the DLDR.

scholarly journals Influence of Selected Multiaxial Stress Paths on Fatigue Estimation under Variable Amplitude Loading

2021 ◽  
Author(s):  
Jan Papuga ◽  
Matúš Margetin ◽  
Vladimír Chmelko
Keyword(s):  
Experimental Data ◽  
Fatigue Life ◽  
High Cycle Fatigue ◽  
Multiaxial Loading ◽  
Cycle Fatigue ◽  
Variable Amplitude ◽  
Life Estimation ◽  
Fatigue Life Estimation ◽  
Shift Effect ◽  
Fatigue Estimation

The paper discusses solutions used for estimating fatigue life under variable amplitude multiaxial loading in the high-cycle fatigue domain. Various concurring effects are treated, and their proposed solutions are commented upon. The focus is on the categories of the phase shift effect and of cycle counting. It is concluded that the available experimental data are not sufficient to substantiate a clear decision to follow a definite algorithm. An example of own new experimental data is provided, and the fatigue life estimation run to highlight some more points open for discussion.

Defect-based probabilistic fatigue life estimation model for an additively manufactured aluminum alloy

2020 ◽  
Vol 798 ◽  
pp. 140082 ◽  
Author(s):  
Ravi Sankar Haridas ◽  
Saket Thapliyal ◽  
Priyanka Agrawal ◽  
Rajiv S. Mishra
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Estimation Model ◽  
Life Estimation ◽  
Fatigue Life Estimation

Load Spectrum Compiling and Fatigue Life Estimation of the Automobile Wheel Hub

2020 ◽  
Vol 13 ◽  
Author(s):  
Xintian Liu ◽  
Yang Qu ◽  
Xiaobing Yang ◽  
Yongfeng Shen
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Two Dimensional ◽  
Load Spectrum ◽  
One Dimensional ◽  
Life Estimation ◽  
Load Spectra ◽  
Fatigue Life Estimation ◽  
Program Load Spectrum ◽  
Program Load

Background:: In the process of high-speed driving, the wheel hub is constantly subjected to the impact load from the ground. Therefore, it is important to estimate the fatigue life of the hub in the design and production process. Objective:: This paper introduces a method to study the fatigue life of car hub based on the road load collected from test site. Methods:: Based on interval analysis, the distribution characteristics of load spectrum are analyzed. The fatigue life estimation of one - dimensional and two - dimensional load spectra is compared by compiling load spectra. Results:: According to the S-N curve cluster and the one-dimensional program load spectrum, the estimated range fatigue life of the hub is 397,100 km to 529,700 km. For unsymmetrical cyclic loading, each level means and amplitude of load were obtained through the Goodman fatigue empirical formula, and then according to S-N curve clusters in the upper and lower curves and two-dimensional program load spectrum, estimates the fatigue life of wheel hub of the interval is 329900 km to 435200 km, than one-dimensional load spectrum fatigue life was reduced by 16.9% - 17.8%. Conclusion:: This paper lays a foundation for the prediction of fatigue life and the bench test of fatigue durability of auto parts subjected to complex and variable random loads. At the same time, the research method can also be used to estimate the fatigue life of other bearing parts or high-speed moving parts and assemblies.

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