Fatigue Life Predictions by Coupling Finite Element and Multibody Systems Calculations

1997 ◽  
Author(s):  
Stefan Dietz ◽  
Helmuth Netter ◽  
Delf Sachau
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Elastic Body ◽  
Multibody Systems ◽  
Life Prediction ◽  
Fatigue Life Prediction ◽  
Dynamic Loads ◽  
Multibody Simulation ◽  
Bogie Frame ◽  
Life Predictions

Abstract The dynamic loads and accelerations acting on a railway bogie are predicted by multibody simulation. The bogie frame is considered as an elastic body of the MBS-model, in which elastic displacements are represented by eigen and staticmodes. Stresses are calculated for the most stressed locations of a bogie in the MBS-postprocessor. Based on these a fatigue life prediction is carried out.

Integrated Computational Durability Analysis

1993 ◽  
Vol 115 (4) ◽  
pp. 492-499 ◽  
Author(s):  
W. K. Baek ◽  
R. I. Stephens ◽  
B. Dopker
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Life Prediction ◽  
Dynamic Stress ◽  
Local Strain ◽  
Fatigue Life Prediction ◽  
Dynamic Loads ◽  
Finite Element Stress Analysis ◽  
Multibody Dynamic ◽  
Crack Initiation Life

A computer aided analysis method is described for durability assessment in the early design stages using multibody dynamic analysis, finite element stress analysis, and fatigue life prediction methods. From multibody dynamic analysis of a mechanical system, dynamic loads of a mechanical component were calculated. Finite element stress analysis with substructuring techniques produced accurate stress fields for the component. From the dynamic loads and the stress field of the component, a dynamic stress history at the critical location was produced using the superposition principle. Using Neuber’s rule, a local strain time history was produced from the dynamic stress history. The local strain based fatigue life prediction method was then used to predict “crack initiation” life of the critical component. The predicted fatigue crack initiation life was verified by experimental durability tests. This methodology can be combined with identification of weak links and optimization techniques such that the design optimization for an entire mechanical system based upon durability is possible during the early product development stage.

Fatigue Life Prediction of Mooring Chains Subjected to Tension and Out of Plane Bending

2009 ◽  
Author(s):  
Tom Lassen ◽  
Eirik Storvoll ◽  
Arild Bech
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Life Prediction ◽  
Hot Spot ◽  
Fatigue Life Prediction ◽  
Combined Loading ◽  
Chain Segment ◽  
Out Of Plane ◽  
Plane Bending ◽  
Life Predictions

The present paper describes the behaviour of chain segments that are subjected to pretension and a rotation angle at the segment end. The behaviour such segments has been investigated both experimentally and by finite element modelling. The purpose is to carry out fatigue life predictions. A full scale test with a studless chain segment with a diameter of 125 mm has been carried out to shed more light on the behaviour. The test corroborated the assumption that the chain segment behaves semi-rigidly under the given conditions due to locking of the inter-link hinge mechanism. The influence of various important parameters on the bending effect was studied. The chain segment has a significant flexural stiffness and an intra-link bending curvature for links that are in a flat position with respect to the inflicted end rotation. The associated Out of Plane Bending (OPB) stresses are significant for critical links close to the end hang-off. This effect must be taken into account when carrying out fatigue life predictions. There is still no guidance given in rules and regulations for this case. In the present work it is suggested that a hot spot method is applied for fatigue life predictions. Under a combined loading mode, defined by tension and OPB, the maximum principal stress range in the link bend area must be determined by refined finite element analysis. Subsequently, the fatigue life can be predicted by using an appropriate hot spot S-N curve. The paper points out how a good fatigue design of the hang-off area can reduce the effect of OPB. A Buoy Turret Loading (BTL) is used as a case study to demonstrate both the design proposal and the fatigue life prediction methodology.

TTK Chitra tilting disc heart valve model TC2: An assessment of fatigue life and durability

2017 ◽  
Vol 231 (8) ◽  
pp. 758-765 ◽  
Author(s):  
NN Subhash ◽  
Adathala Rajeev ◽  
Sreedharan Sujesh ◽  
CV Muraleedharan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Heart Valve ◽  
Life Prediction ◽  
Heart Valves ◽  
Failure Modes ◽  
Fatigue Life Prediction ◽  
Element Analysis ◽  
Valve Model

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.

Application of Artificial Neural Network for Fatigue Life Prediction

2005 ◽  
Vol 297-300 ◽  
pp. 96-101
Author(s):  
Ishak Abdul Azid ◽  
Lee Kor Oon ◽  
Ong Kang Eu ◽  
K.N. Seetharamu ◽  
Ghulam Abdul Quadir
Keyword(s):  
Neural Network ◽  
Finite Element ◽  
Fatigue Life ◽  
Solder Joint ◽  
Finite Element Simulation ◽  
Life Prediction ◽  
Fatigue Life Prediction ◽  
Element Simulation ◽  
Parametric Studies ◽  
Solder Joint Fatigue

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.

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