scholarly journals EFFICIENT FATIGUE LIFE ASSESSMENT OF COMPOSITE MATERIALS BY USING A HYBRID SURROGATE MODELING

2021 ◽  
Vol 2 (2) ◽  
pp. 28
Author(s):  
Prima P Airlangga ◽  
Azzah Dyah Pramata ◽  
Mas Irfan P Hidayat
Keyword(s):  
Fatigue Life ◽  
Composite Materials ◽  
Surrogate Modeling ◽  
Life Assessment ◽  
Fatigue Life Assessment

Neural Networks with Radial Basis Function and NARX Structure for Material Lifetime Assessment Application

2011 ◽  
Vol 277 ◽  
pp. 143-150 ◽  
Author(s):  
M.I.P. Hidayat ◽  
Wajan Berata
Keyword(s):  
Neural Networks ◽  
Fatigue Life ◽  
Composite Materials ◽  
Radial Basis Function ◽  
Basis Function ◽  
Life Assessment ◽  
Analysis And Design ◽  
Fatigue Life Assessment ◽  
Radial Basis ◽  
Narx Model

In the present paper, neural networks (NN) with radial basis function and non-linear auto-regressive exogenous inputs (NARX) structure is introduced and first applied for predicting fatigue lives of composite materials. Fatigue life assessment of multivariable amplitude loading linked to the concept of constant life diagrams (CLD), the well known concept in fatigue of material analysis and design, was investigated. With this respect, fatigue life assessment using the RBFNN-NARX model was realized as one-step ahead prediction with respect to each stress level-S corresponding to stress ratio values-R arranged in such a way that transition took place from a fatigue region to another one in the CLD. As a result, composite materials lifetime assessment can be fashioned for a wide spectrum of loading in an efficient manner. In addition, the produced mean squared error (MSE) values of fatigue life prediction results of the RBFNN-NARX model competed favorably, even better, with those of the MLP-NARX model previously obtained. The simulation results for different multidirectional laminates of polymeric-based composites and loading situations were presented and discussed.

Multi-Axial Fatigue Life Assessment of Wind Turbine Structural Components

2010 ◽  
Author(s):  
Zhigang Wei ◽  
Thomas P. Forte
Keyword(s):  
Fatigue Life ◽  
Composite Materials ◽  
Composite Structures ◽  
Fatigue Loading ◽  
Life Assessment ◽  
Fiber Reinforced ◽  
Reinforced Plastics ◽  
Fatigue Life Assessment ◽  
Fiber Reinforced Plastics ◽  
Axial Fatigue

Modern wind turbines, which are usually made of composite materials, are fatigue critical structures that are subjected to variable multi-axial fatigue loading. Therefore, they should be designed as safely as necessary to withstand the fatigue loads over the designed life time. Path-Dependent Maximum Range (PDMR) is a multi-axial fatigue life assessment tool developed by Battelle researchers. PDMR has been successfully applied to fatigue analysis of isotropic structures under general variable amplitude, multi-axial fatigue loading histories. The effectiveness of the PDMR method has been validated by its ability to correlate a large amount of fatigue data available in the literature. For uniaxial loading data, PDMR gives exactly the same results as ASTM standard Rainflow cycle counting method. In this paper, the PDMR method is extended to composite materials, such as glass fiber reinforced plastics (GFRP) and carbon fiber reinforced plastics (CFRP). The proposed multi-axial fatigue damage model effectively correlates fatigue lives of unidirectional composites for various off-axis ply angles under cyclic tensile loading. With this extended capability, the PDMR can now be used to assess the multi-axial fatigue life of composite structures used in wind energy industry.

scholarly journals Mapping of scatter in fatigue life assessment of welded structures—a round-robin study

2021 ◽  
Author(s):  
Gustav Hultgren ◽  
Mansoor Khurshid ◽  
Peter Haglund ◽  
Zuheir Barsoum
Keyword(s):  
Fatigue Life ◽  
Round Robin ◽  
Life Assessment ◽  
Fatigue Life Assessment ◽  
Fatigue Life Estimation ◽  
Box Structures ◽  
Load Carrying ◽  
Local Stresses ◽  
Sources Of Variation ◽  
Global And Local

AbstractA round-robin study has been carried out within a national project in Sweden with the addition of an international participant, where several industrial partners and universities are participating. The project aims to identify variation and sources of variation in welding production, map scatter in fatigue life estimation, and define and develop concepts to reduce these, in all steps of product development. The participating organisations were asked to carry out fatigue life assessment of welded box structures, which is a component in load-carrying structures. The estimations of fatigue life have also been compared with fatigue test results. Detailed drawings, loads and material data were also given to the participants. The participants were supposed to use assessment methods based on global and local stresses using the design codes or recommendations they currently use in-house. Differences were identified between both methods and participants using the same codes/recommendations. Applicability and conditions from the cases in the codes were also identified to be differently evaluated between the participants. It could be concluded that for the applied cases the nominal stress method often overestimated the fatigue life and had a high scatter in the estimations by different participants. The effective notch method is conservative in comparison to the life of tested components with little scatter between the results derived by the participants.

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