The Experts below are selected from a list of 143937 Experts worldwide ranked by ideXlab platform
Enrique Castillo - One of the best experts on this subject based on the ideXlab platform.
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design of a composite beam using the failure probability Safety Factor method
International Journal for Numerical Methods in Engineering, 2005Co-Authors: Enrique Castillo, Roberto Minguez, A Ruizteran, Alfonso FernandezcanteliAbstract:The paper shows the practical importance of the failure probability-Safety Factor method for designing engineering works. The method provides an automatic design tool by optimizing an objective function subject to the standard geometric and code constraints, and two more sets of constraints, that guarantee some given Safety Factors and failure probability bounds, associated with a given set of failure modes. Since a direct solution of the optimization problem is not possible, the method proceeds as a sequence of three steps: (a) an optimal classical design, based on given Safety Factors, is done, (b) failure probabilities or bounds of all failure modes are calculated, and (c) Safety Factors bounds are adjusted. This implies a double Safety check that leads to safer structures and designs less prone to wrong or unrealistic probability assumptions, and to excessively small (unsafe) or large (costly) Safety Factors. Finally, the actual global or combined probabilities of the different failure modes and their correlation are calculated using a Monte Carlo simulation. In addition, a sensitivity analysis is performed. To this end, the optimization problems are transformed into another equivalent ones, in which the data parameters are converted into artificial variables. In this way, some variables of the dual associated problems become the desired sensitivities. The method is illustrated by its application to the design of a composite beam. Copyright 2004 © John Wiley & Sons, Ltd.
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an alternative approach for addressing the failure probability Safety Factor method with sensitivity analysis
Reliability Engineering & System Safety, 2003Co-Authors: Enrique Castillo, Antonio J Conejo, Roberto Minguez, Carmen CastilloAbstract:Abstract The paper introduces a method for solving the failure probability-Safety Factor problem for designing engineering works proposed by Castillo et al. that optimizes an objective function subject to the standard geometric and code constraints, and two more sets of constraints that simultaneously guarantee given Safety Factors and failure probability bounds associated with a given set of failure modes. The method uses the dual variables and is especially convenient to perform a sensitivity analysis, because sensitivities of the objective function and the reliability indices can be obtained with respect to all data values. To this end, the optimization problems are transformed into other equivalent ones, in which the data parameters are converted into artificial variables, and locked to their actual values. In this way, some variables of the associated dual problems become the desired sensitivities. In addition, using the proposed methodology, calibration of codes based on partial Safety Factors can be done. The method is illustrated by its application to the design of a simple rubble mound breakwater and a bridge crane.
Roberto Minguez - One of the best experts on this subject based on the ideXlab platform.
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design of a composite beam using the failure probability Safety Factor method
International Journal for Numerical Methods in Engineering, 2005Co-Authors: Enrique Castillo, Roberto Minguez, A Ruizteran, Alfonso FernandezcanteliAbstract:The paper shows the practical importance of the failure probability-Safety Factor method for designing engineering works. The method provides an automatic design tool by optimizing an objective function subject to the standard geometric and code constraints, and two more sets of constraints, that guarantee some given Safety Factors and failure probability bounds, associated with a given set of failure modes. Since a direct solution of the optimization problem is not possible, the method proceeds as a sequence of three steps: (a) an optimal classical design, based on given Safety Factors, is done, (b) failure probabilities or bounds of all failure modes are calculated, and (c) Safety Factors bounds are adjusted. This implies a double Safety check that leads to safer structures and designs less prone to wrong or unrealistic probability assumptions, and to excessively small (unsafe) or large (costly) Safety Factors. Finally, the actual global or combined probabilities of the different failure modes and their correlation are calculated using a Monte Carlo simulation. In addition, a sensitivity analysis is performed. To this end, the optimization problems are transformed into another equivalent ones, in which the data parameters are converted into artificial variables. In this way, some variables of the dual associated problems become the desired sensitivities. The method is illustrated by its application to the design of a composite beam. Copyright 2004 © John Wiley & Sons, Ltd.
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an alternative approach for addressing the failure probability Safety Factor method with sensitivity analysis
Reliability Engineering & System Safety, 2003Co-Authors: Enrique Castillo, Antonio J Conejo, Roberto Minguez, Carmen CastilloAbstract:Abstract The paper introduces a method for solving the failure probability-Safety Factor problem for designing engineering works proposed by Castillo et al. that optimizes an objective function subject to the standard geometric and code constraints, and two more sets of constraints that simultaneously guarantee given Safety Factors and failure probability bounds associated with a given set of failure modes. The method uses the dual variables and is especially convenient to perform a sensitivity analysis, because sensitivities of the objective function and the reliability indices can be obtained with respect to all data values. To this end, the optimization problems are transformed into other equivalent ones, in which the data parameters are converted into artificial variables, and locked to their actual values. In this way, some variables of the associated dual problems become the desired sensitivities. In addition, using the proposed methodology, calibration of codes based on partial Safety Factors can be done. The method is illustrated by its application to the design of a simple rubble mound breakwater and a bridge crane.
Carmen Castillo - One of the best experts on this subject based on the ideXlab platform.
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an alternative approach for addressing the failure probability Safety Factor method with sensitivity analysis
Reliability Engineering & System Safety, 2003Co-Authors: Enrique Castillo, Antonio J Conejo, Roberto Minguez, Carmen CastilloAbstract:Abstract The paper introduces a method for solving the failure probability-Safety Factor problem for designing engineering works proposed by Castillo et al. that optimizes an objective function subject to the standard geometric and code constraints, and two more sets of constraints that simultaneously guarantee given Safety Factors and failure probability bounds associated with a given set of failure modes. The method uses the dual variables and is especially convenient to perform a sensitivity analysis, because sensitivities of the objective function and the reliability indices can be obtained with respect to all data values. To this end, the optimization problems are transformed into other equivalent ones, in which the data parameters are converted into artificial variables, and locked to their actual values. In this way, some variables of the associated dual problems become the desired sensitivities. In addition, using the proposed methodology, calibration of codes based on partial Safety Factors can be done. The method is illustrated by its application to the design of a simple rubble mound breakwater and a bridge crane.
Alfonso Fernandezcanteli - One of the best experts on this subject based on the ideXlab platform.
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design of a composite beam using the failure probability Safety Factor method
International Journal for Numerical Methods in Engineering, 2005Co-Authors: Enrique Castillo, Roberto Minguez, A Ruizteran, Alfonso FernandezcanteliAbstract:The paper shows the practical importance of the failure probability-Safety Factor method for designing engineering works. The method provides an automatic design tool by optimizing an objective function subject to the standard geometric and code constraints, and two more sets of constraints, that guarantee some given Safety Factors and failure probability bounds, associated with a given set of failure modes. Since a direct solution of the optimization problem is not possible, the method proceeds as a sequence of three steps: (a) an optimal classical design, based on given Safety Factors, is done, (b) failure probabilities or bounds of all failure modes are calculated, and (c) Safety Factors bounds are adjusted. This implies a double Safety check that leads to safer structures and designs less prone to wrong or unrealistic probability assumptions, and to excessively small (unsafe) or large (costly) Safety Factors. Finally, the actual global or combined probabilities of the different failure modes and their correlation are calculated using a Monte Carlo simulation. In addition, a sensitivity analysis is performed. To this end, the optimization problems are transformed into another equivalent ones, in which the data parameters are converted into artificial variables. In this way, some variables of the dual associated problems become the desired sensitivities. The method is illustrated by its application to the design of a composite beam. Copyright 2004 © John Wiley & Sons, Ltd.
Patrick Moriarty - One of the best experts on this subject based on the ideXlab platform.
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Safety Factor calibration for wind turbine extreme loads
Wind Energy, 2008Co-Authors: Patrick MoriartyAbstract:Proper prediction of long-term extreme values for operating wind turbine loads and deflections is a critical component of wind turbine design. Direct observations or simulations of long-term extremes are not yet available; therefore, these predictions rely on some combination of large numbers of simulations and extrapolation. Extrapolation methods themselves can have significant uncertainty, and they also require that the wind turbine designer have a greater level of statistical expertise--Factors that make the methods less attractive for industrial application. As an alternative to extrapolation, Safety Factors can be calibrated using techniques that allow designers to use smaller data sets. To calculate such Factors, a series of simulations was used to extrapolate 50 year extreme values for a 5 MW wind turbine. Two methods are proposed for calculating such Safety Factors: one based on the mean and standard deviation of extreme values, and one based on the median of extreme values. Through a process of random sampling without replacement, the Safety Factor based on the median of extreme values was found to be less variable and also more independent of the number of simulations. The Safety Factors required were as large as 1.7, or were only 1.25 if rotor thrust loads weremore » considered the dominant design drivers.« less
