Fatigue Life Prediction Methods Evaluation for Remanufacturing Mechanical Parts

2013 ◽  
Vol 579-580 ◽  
pp. 573-579 ◽  
Author(s):  
Jian Xin Weng ◽  
Wen Hui Yue ◽  
Yong Xing Zhu ◽  
Peng Hui Duan

Aiming at the demand of remanufacturing mechanical parts fatigue life prediction, the main methods of fatigue life prediction are reviewed and summarized. The finite element and dynamics combined simulation method has been widely used at present, whose advantages are that it is suitable for most of the mechanical parts, and the forecast cycle is short, and it can be analyzed combining with the parts actual working condition, but the prediction accuracy depends on the comprehensive degree to the service condition. The experimental method is the most traditional method, and the fatigue life value obtained by the method is reliable, but the method is entirely depend on experience, and the cost of experiments is expensive, so the feasibility is bad. The fatigue life analysis method can lower the dependence on large number of experiments, but there is a great distance between the predicting fatigue life and actual fatigue life in working environment. The metal magnetic memory non-destructive testing method doesnt damage the testing objects, but the method is still in the stage of further research at present. Finally, taking the number of experiments, prediction cycle, prediction accuracy, prediction cost and the complex degree of the principle involved in the prediction process as evaluation indexes, the finite element and dynamics combined simulation method is the best fatigue life prediction method according to the score values of each method calculated by the quantitative scores based on the expert evaluation method.

Author(s):  
NN Subhash ◽  
Adathala Rajeev ◽  
Sreedharan Sujesh ◽  
CV Muraleedharan

Average age group of heart valve replacement in India and most of the Third World countries is below 30 years. Hence, the valve for such patients need to be designed to have a service life of 50 years or more which corresponds to 2000 million cycles of operation. The purpose of this study was to assess the structural performance of the TTK Chitra tilting disc heart valve model TC2 and thereby address its durability. The TC2 model tilting disc heart valves were assessed to evaluate the risks connected with potential structural failure modes. To be more specific, the studies covered the finite element analysis–based fatigue life prediction and accelerated durability testing of the tilting disc heart valves for nine different valve sizes. First, finite element analysis–based fatigue life prediction showed that all nine valve sizes were in the infinite life region. Second, accelerated durability test showed that all nine valve sizes remained functional for 400 million cycles under experimental conditions. The study ensures the continued function of TC2 model tilting disc heart valves over duration in excess of 50 years. The results imply that the TC2 model valve designs are structurally safe, reliable and durable.


2005 ◽  
Vol 297-300 ◽  
pp. 96-101
Author(s):  
Ishak Abdul Azid ◽  
Lee Kor Oon ◽  
Ong Kang Eu ◽  
K.N. Seetharamu ◽  
Ghulam Abdul Quadir

An extensively published and correlated solder joint fatigue life prediction methodology is incorporated by which finite element simulation results are translated into estimated cycles to failure. This study discusses the analysis methodologies as implemented in the ANSYSTM finite element simulation software tool. Finite element models are used to study the effect of temperature cycles on the solder joints of a flip chip ball grid array package. Through finite element simulation, the plastic work or the strain-energy density of the solder joints are determined. Using an established methodology, the plastic work obtained through simulation is translated into solder joint fatigue life [1]. The corresponding results for the solder joint fatigue life are used for parametric studies. Artificial Neural Network (ANN) has been used to consolidate the parametric studies.


Author(s):  
John M. Emery ◽  
Jeffrey E. Bozek ◽  
Anthony R. Ingraffea

The fatigue resistance of metallic structures is inherently random due to environmental and boundary conditions, and microstructural geometry, including discontinuities, and material properties. A new methodology for fatigue life prediction is under development to account for these sources of randomness. One essential aspect of the methodology is the ability to perform truly multiscale simulations: simulations that directly link the boundary conditions on the structural length scale to the damage mechanisms of the microstructural length scale. This presentation compares and contrasts two multiscale methods suitable for fatigue life prediction. The first is a brute force method employing the widely-used multipoint constraint technique which couples a finite element model of the microstructure within the finite element model of the structural component. The second is a more subtle, modified multi-grid method which alternates analyses between the two finite element models while representing the evolving microstructural damage. Examples and comparisons are made for several geometries and preliminary validation is achieved with comparison to experimental tests conducted by the Northrop Grumman Corporation on a wing-panel structural geometry.


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