The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
John F Mandell - One of the best experts on this subject based on the ideXlab platform.
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1 EFFECT OF MEAN STRESS ON THE DAMAGE OF WIND TURBINE BLADES*
2015Co-Authors: Herbert J Sutherland, John F MandellAbstract:In many analyses of composite wind turbine blades, the effects of mean stress on the determination of damage are either ignored completely or they are characterized inadequately. An updated Goodman Diagram for the fiberglass materials that are typically used in wind turbine blades has been released recently. This Diagram, which is based on the MSU/DOE Fatigue Database, contains detailed information at thirteen R-values. This Diagram is the most detailed to date, and it includes several loading conditions that have been poorly represented in earlier studies. This formulation allows the effects of mean stress on damage calculations to be evaluated. The evaluation presented here uses four formulations for the S-N behavior of the fiberglass. In the first analysis, the S-N curve for the composite is assumed to be independent of mean stress and to have a constant slope. The second is a linear Goodman Diagram, the third is a bi-linear Goodman Diagram and the fourth is the full Goodman Diagram. Two sets of load spectra, obtained by the LIST (Long term Inflow and Structural Test) program, are used for this *Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin company, for the U.S
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The Effect of Mean Stress on Damage Predictions for Spectral Loading of Fiberglass Composite
2014Co-Authors: Herbert J Sutherland, John F MandellAbstract:In many analyses of wind turbine blades, the effects of mean stress on the determination of damage in composite blades are either ignored completely or they are characterized inadequately. Mandell, et al [1] have recently presented an updated Goodman Diagram for a fiberglass material that is typical of the materials used in wind turbine blades. Their formulation uses the MSU/DOE Fatigue Data Base [2] to develop a Goodman Diagram with detailed information at thirteen R-values. Using these data, linear, bi-linear and full Goodman Diagrams are constructed using mean and “95/95 ” fits to the data. The various Goodman Diagrams are used to predict the failure stress for coupons tested using the WISPERX spectrum [3]. Three models are used in the analyses. The first is the linear Miner’s rule commonly used by the wind industry to predict failure (service lifetimes). The second is a nonlinear variation of Miner’s rule which computes a nonlinear Miner’s Sum based upon an exponential degradation parameter. The third is a generalized nonlinear residual strength model that also relies on an exponential degradation parameter. The results illustrate that Miner’s rule does not predict failure very well. When the mean Goodman Diagram is used, the nonlinear models predict failures near the mean of the experimental data, and when the 95/95 Goodman Diagram is used, they predict the lower bound of the measured data very well
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UPDATED Goodman DiagramS FOR FIBERGLASS COMPOSITE MATERIALS USING THE DOE/MSU FATIGUE DATABASE
2014Co-Authors: Herbert J Sutherland, John F MandellAbstract:Recent expansions of the DOE/MSU Composite Fatigue Database permit the construction of a high resolution Goodman Diagram with detailed information at thirteen R-values (minimum stress / maximum stress). This Goodman Diagram is the most detailed to date, including several loading conditions which have been poorly represented in earlier studies. The data for a single E-glass/polyester material system are extracted from the MSU/DOE Fatigue Database to construct the Goodman Diagrams. Diagrams are constructed using both mean fits to the data and 95/95 fits. These formulations allow the effects of mean stress on damage calculations to be evaluated. Two sets of load spectra are analyzed. The first set is experimentally-determined load spectra obtained from operating wind turbines, and the second is the WISPERX load spectrum. The analysis of the turbine load spectra illustrates a significant overestimation of the equivalent fatigue loads when the mean stress is not considered in the calculation. The analysis of coupon data using the WISPERX spectrum illustrates that the Miner’s rule does not predict failure very well. 1 *Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin company, for the U.S
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the effect of mean stress on damage predictions for spectral loading of fibreglass composite coupons
Wind Energy, 2005Co-Authors: Herbert J Sutherland, John F MandellAbstract:In many analyses of wind turbine blades the effects of mean stress on the determination of damage in composite blades are either ignored completely or characterized inadequately. Mandell et al. have recently presented an updated Goodman Diagram for a fibreglass material that is typical of the materials used in wind turbine blades. Their formulation uses the MSU/DOE fatigue database to develop a Goodman Diagram with detailed information at 13 R-values. Using these data, linear, bilinear and full Goodman Diagrams are constructed using mean and ‘95/95’ fits to the data. The various Goodman Diagrams are used to predict the failure stress for coupons tested using the WISPERX spectrum. Three models are used in the analyses. The first is the linear Miner's rule commonly used by the wind industry to predict failure (service lifetimes). The second is a non-linear variation of Miner's rule which computes a non-linear Miner's residual strength based upon an exponential degradation parameter. The third is a generalized non-linear residual strength model that also relies on an exponential degradation parameter. The results illustrate that Miner's rule does not predict failure very well. When the mean full Goodman Diagram is used, the non-linear models predict failures near the mean of the experimental data, and when the 95/95 Goodman Diagram is used, they predict the lower bound of the measured data very well. Published in 2004 by John Wiley & Sons, Ltd.
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effect of mean stress on the damage of wind turbine blades
Journal of Solar Energy Engineering-transactions of The Asme, 2004Co-Authors: Herbert J Sutherland, John F MandellAbstract:In many analyses of composite wind turbine blades, the effects of mean stress on the determination of damage are either ignored completely or they are characterized inadequately. An updated Goodman Diagram for the fiberglass materials that are typically used in wind turbine blades has been released recently. This Diagram, which is based on the MSU/DOE Fatigue Database, contains detailed information at thirteen Rvalues. This Diagram is the most detailed to date, and it includes several loading conditions that have been poorly represented in earlier studies. This formulation allows the effects of mean stress on damage calculations to be evaluated. The evaluation presented here uses four formulations for the S-N behavior of the fiberglass. In the first analysis, the S-N curve for the composite is assumed to be independent of mean stress and to have a constant slope. The second is a linear Goodman Diagram, the third is a bi-linear Goodman Diagram and the fourth is the full Goodman Diagram. Two sets of load spectra, obtained by the LIST (Long term Inflow and Structural Test) program, are used for this evaluation. The results of the analyses, equivalent fatigue loads and damage predictions, are compared to one another. These results illustrate a significant overestimation of the equivalent fatigue loads when the mean stress is not considered in the calculation. And, the results from the updated Goodman Diagram illustrate that there are a significant differences in accumulated damage when the Goodman Diagram
Herbert J Sutherland - One of the best experts on this subject based on the ideXlab platform.
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1 EFFECT OF MEAN STRESS ON THE DAMAGE OF WIND TURBINE BLADES*
2015Co-Authors: Herbert J Sutherland, John F MandellAbstract:In many analyses of composite wind turbine blades, the effects of mean stress on the determination of damage are either ignored completely or they are characterized inadequately. An updated Goodman Diagram for the fiberglass materials that are typically used in wind turbine blades has been released recently. This Diagram, which is based on the MSU/DOE Fatigue Database, contains detailed information at thirteen R-values. This Diagram is the most detailed to date, and it includes several loading conditions that have been poorly represented in earlier studies. This formulation allows the effects of mean stress on damage calculations to be evaluated. The evaluation presented here uses four formulations for the S-N behavior of the fiberglass. In the first analysis, the S-N curve for the composite is assumed to be independent of mean stress and to have a constant slope. The second is a linear Goodman Diagram, the third is a bi-linear Goodman Diagram and the fourth is the full Goodman Diagram. Two sets of load spectra, obtained by the LIST (Long term Inflow and Structural Test) program, are used for this *Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin company, for the U.S
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The Effect of Mean Stress on Damage Predictions for Spectral Loading of Fiberglass Composite
2014Co-Authors: Herbert J Sutherland, John F MandellAbstract:In many analyses of wind turbine blades, the effects of mean stress on the determination of damage in composite blades are either ignored completely or they are characterized inadequately. Mandell, et al [1] have recently presented an updated Goodman Diagram for a fiberglass material that is typical of the materials used in wind turbine blades. Their formulation uses the MSU/DOE Fatigue Data Base [2] to develop a Goodman Diagram with detailed information at thirteen R-values. Using these data, linear, bi-linear and full Goodman Diagrams are constructed using mean and “95/95 ” fits to the data. The various Goodman Diagrams are used to predict the failure stress for coupons tested using the WISPERX spectrum [3]. Three models are used in the analyses. The first is the linear Miner’s rule commonly used by the wind industry to predict failure (service lifetimes). The second is a nonlinear variation of Miner’s rule which computes a nonlinear Miner’s Sum based upon an exponential degradation parameter. The third is a generalized nonlinear residual strength model that also relies on an exponential degradation parameter. The results illustrate that Miner’s rule does not predict failure very well. When the mean Goodman Diagram is used, the nonlinear models predict failures near the mean of the experimental data, and when the 95/95 Goodman Diagram is used, they predict the lower bound of the measured data very well
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UPDATED Goodman DiagramS FOR FIBERGLASS COMPOSITE MATERIALS USING THE DOE/MSU FATIGUE DATABASE
2014Co-Authors: Herbert J Sutherland, John F MandellAbstract:Recent expansions of the DOE/MSU Composite Fatigue Database permit the construction of a high resolution Goodman Diagram with detailed information at thirteen R-values (minimum stress / maximum stress). This Goodman Diagram is the most detailed to date, including several loading conditions which have been poorly represented in earlier studies. The data for a single E-glass/polyester material system are extracted from the MSU/DOE Fatigue Database to construct the Goodman Diagrams. Diagrams are constructed using both mean fits to the data and 95/95 fits. These formulations allow the effects of mean stress on damage calculations to be evaluated. Two sets of load spectra are analyzed. The first set is experimentally-determined load spectra obtained from operating wind turbines, and the second is the WISPERX load spectrum. The analysis of the turbine load spectra illustrates a significant overestimation of the equivalent fatigue loads when the mean stress is not considered in the calculation. The analysis of coupon data using the WISPERX spectrum illustrates that the Miner’s rule does not predict failure very well. 1 *Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin company, for the U.S
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the effect of mean stress on damage predictions for spectral loading of fibreglass composite coupons
Wind Energy, 2005Co-Authors: Herbert J Sutherland, John F MandellAbstract:In many analyses of wind turbine blades the effects of mean stress on the determination of damage in composite blades are either ignored completely or characterized inadequately. Mandell et al. have recently presented an updated Goodman Diagram for a fibreglass material that is typical of the materials used in wind turbine blades. Their formulation uses the MSU/DOE fatigue database to develop a Goodman Diagram with detailed information at 13 R-values. Using these data, linear, bilinear and full Goodman Diagrams are constructed using mean and ‘95/95’ fits to the data. The various Goodman Diagrams are used to predict the failure stress for coupons tested using the WISPERX spectrum. Three models are used in the analyses. The first is the linear Miner's rule commonly used by the wind industry to predict failure (service lifetimes). The second is a non-linear variation of Miner's rule which computes a non-linear Miner's residual strength based upon an exponential degradation parameter. The third is a generalized non-linear residual strength model that also relies on an exponential degradation parameter. The results illustrate that Miner's rule does not predict failure very well. When the mean full Goodman Diagram is used, the non-linear models predict failures near the mean of the experimental data, and when the 95/95 Goodman Diagram is used, they predict the lower bound of the measured data very well. Published in 2004 by John Wiley & Sons, Ltd.
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effect of mean stress on the damage of wind turbine blades
Journal of Solar Energy Engineering-transactions of The Asme, 2004Co-Authors: Herbert J Sutherland, John F MandellAbstract:In many analyses of composite wind turbine blades, the effects of mean stress on the determination of damage are either ignored completely or they are characterized inadequately. An updated Goodman Diagram for the fiberglass materials that are typically used in wind turbine blades has been released recently. This Diagram, which is based on the MSU/DOE Fatigue Database, contains detailed information at thirteen Rvalues. This Diagram is the most detailed to date, and it includes several loading conditions that have been poorly represented in earlier studies. This formulation allows the effects of mean stress on damage calculations to be evaluated. The evaluation presented here uses four formulations for the S-N behavior of the fiberglass. In the first analysis, the S-N curve for the composite is assumed to be independent of mean stress and to have a constant slope. The second is a linear Goodman Diagram, the third is a bi-linear Goodman Diagram and the fourth is the full Goodman Diagram. Two sets of load spectra, obtained by the LIST (Long term Inflow and Structural Test) program, are used for this evaluation. The results of the analyses, equivalent fatigue loads and damage predictions, are compared to one another. These results illustrate a significant overestimation of the equivalent fatigue loads when the mean stress is not considered in the calculation. And, the results from the updated Goodman Diagram illustrate that there are a significant differences in accumulated damage when the Goodman Diagram
Theodore Nicholas - One of the best experts on this subject based on the ideXlab platform.
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on the use of critical distance theories for the prediction of the high cycle fatigue limit stress in notched ti 6al 4v
International Journal of Fatigue, 2005Co-Authors: David B Lanning, Theodore Nicholas, George K. HaritosAbstract:Abstract Methods are investigated for predicting the high cycle fatigue (HCF) lives of notched cylindrical Ti–6Al–4V specimens using critical distance concepts that employ the stress distribution in the vicinity of the notch. Cylindrical fatigue specimens had circumferential V-notches with a range of elastic stress concentration factors ( k t =1.97–4.07). Notched and unnotched specimens were cycled to failure using a step-loading technique to generate points on a Haigh (Goodman) Diagram for a constant fatigue life of 10 6 cycles. Finite element solutions were generated to provide stress distributions for the notched gage sections. The stress distributions were used in the search for a critical distance over which the quantities of mean stress, stress range, or elastic strain energy may contribute to the fatigue process and can be correlated to similar quantities from smooth, unnotched specimens. If the decrease in the local stress ratio at the notch root for high applied stress ratio is accounted for in the analysis, trends independent of applied stress ratio were found in the calculated critical distances. Predictions based upon the results gave accuracy to within 12% of the experimental fatigue limit stresses and illustrate the method has promise for use in fatigue design of Ti–6Al–4V components.
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Goodman Diagram via vibration based fatigue testing
Journal of Engineering Materials and Technology-transactions of The Asme, 2005Co-Authors: M Herma H She, Onome Scottemuakpo, Theodore Nicholas, Jeffrey CalcaterraAbstract:A new vibration-based fatigue testing methodology for assessing high-cycle turbine engine material fatigue strength at various stress ratios is presented. The idea is to accumulate fatigue energy on a base-excited plate specimen at high frequency resonant modes and to complete a fatigue test in a much more efficient way at very low cost. The methodology consists of (1) a geometrical design procedure, incorporating a finite-element model to characterize the shape of the specimen for ensuring the required stress state/ pattern; (2) a vibration feedback empirical procedure for achieving the high-cycle fatigue experiments with variable-amplitude loading; and finally (3) a pre-strain procedure for achieving various uniaxial stress ratios. The performance of the methodology is demonstrated with experimental results for mild steel, 6061-T6 aluminum, and Ti-6Al-4V plate specimens subjected to a fully reversed bending, uniaxial stress state.
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critical issues in high cycle fatigue
International Journal of Fatigue, 1999Co-Authors: Theodore NicholasAbstract:High cycle fatigue (HCF) failures in materials used in rotating components of gas turbine engines have often been found to be attributable to fatigue loading on materials which have sustained damage from other sources. Damage can be present in the form of initial material or manufacturing defects, or can develop during service operation. Three major sources of in-service damage have been identified which can alter the HCF resistance individually or in conjunction with one another: low cycle fatigue (LCF), foreign object damage (FOD), and fretting. Methodologies for treating such damage in establishing material allowables are considered. Some recent results on the effects of damage on the Haigh (Goodman) Diagram and a discussion of the life management aspects of HCF are presented.
M.-h. H. Shen - One of the best experts on this subject based on the ideXlab platform.
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Reliability assessment of high cycle fatigue design of gas turbine blades using the probabilistic Goodman Diagram
International Journal of Fatigue, 1999Co-Authors: M.-h. H. ShenAbstract:A probability-based procedure has been developed to predict the reliability of gas turbine engine blades subjected to high cycle fatigue. The procedure provides a systemic approach for predicting and designing turbomachinery blading reliability against various potential high cycle fatigue problems for all relevant vibratory modes, and taking into account variability in geometry (e.g. dimensional variation, surface smoothness, etc.). The variability in materials (e.g. damage, cracks, degradation, etc.), unsteady aerodynamics, and structural damping can be also considered in this approach. A reliability prediction was performed on gas turbine blades at high frequency modes (e.g. third strip modes) using a probabilistic vibratory stress distribution in conjunction with the modified Goodman Diagrams. The cumulative reliability and risk assessment are then calculated using the fast probability integration (FPI) technique to construct a novel probabilistic Goodman Diagram which provides lifetime design guide lines for blades and an optimal maintenance strategy in management, in decision-making relating to the PM/inspection scheduling, replacement, and spare parts requirements.
Joseph Calogero - One of the best experts on this subject based on the ideXlab platform.
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Using surrogate models to predict nodal results for fatigue risk analysis
International Journal of Fatigue, 2021Co-Authors: Christopher Thelin, John L. Salmon, Steven E. Gorrell, Spencer Bunnell, Gregory Bird, Christopher Ruoti, Evan Selin, Joseph CalogeroAbstract:Abstract Fatigue life analysis and FEA require high computational costs for aerospace models. Goodman Diagrams are useful tools for determining the fatigue life of a part, and depend on structural and modal FEA simulations. Surrogate models have been used in fatigue analysis to predict the steady stresses and alternating stresses FEA model for every par node enabling a dynamically-updated Goodman Diagram that responds to design parameter changes in real time. This research analyzes a jet engine compressor blade, and compares the accuracy of these nodal surrogate methods to previous surrogate methods where only a single value is predicted for failure analysis. Quantitative data summarizing the error between the single value and full field models are presented for the transonic Purdue blade.
