Rainflow Counting

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Ocampo-martínez Carlos - One of the best experts on this subject based on the ideXlab platform.

  • Health-aware model predictive control of pasteurization plant
    'IOP Publishing', 2018
    Co-Authors: Karimi Pour Fatemeh, Puig Vicenç, Ocampo-martínez Carlos
    Abstract:

    Trabajo presentado a la 13th European Workshop on Advanced Control and Diagnosis (ACD 2016).In order to optimize the trade-off between components life and energy consumption, the integration of a system health management and control modules is required. This paper proposes the integration of model predictive control (MPC) with a fatigue estimation approach that minimizes the damage of the components of a pasteurization plant. The fatigue estimation is assessed with the Rainflow Counting algorithm. Using data from this algorithm, a simplified model that characterizes the health of the system is developed and integrated with MPC. The MPC controller objective is modified by adding an extra criterion that takes into account the accumulated damage. But, a steady-state offset is created by adding this extra criterion. Finally, by including an integral action in the MPC controller, the steady-state error for regulation purpose is eliminated. The proposed control scheme is validated in simulation using a simulator of a utility-scale pasteurization plant.Peer Reviewe

  • Multi–layer health–aware economic predictive control of a pasteurization pilot plant
    'Walter de Gruyter GmbH', 2018
    Co-Authors: Karimi Pour Fatemeh, Puig Cayuela Vicenç, Ocampo-martínez Carlos
    Abstract:

    This paper proposes two different health-aware economic predictive control strategies that aim at minimizing the damage of components in a pasteurization plant. The damage is assessed with a Rainflow-Counting algorithm that allows estimating the components’ fatigue. By using the results obtained from this algorithm, a simplified model that characterizes the health of the system is developed and integrated into the predictive controller. The overall control objective is modified by adding an extra criterion that takes into account the accumulated damage. The first strategy is a single-layer predictive controller with an integral action to eliminate the steady-state error that appears when adding the extra criterion. In order to achieve the best minimal accumulated damage and operational costs, the single-layer approach is improved with a multi-layer control scheme, where the solution of the dynamic optimization problem is obtained from the model in two different time scales. Finally, to achieve the advisable trade-off between minimal accumulated damage and operational costs, both control strategies are compared in simulation over a utility-scale pasteurization plant.Peer Reviewe

  • Multi-layer health-aware economic predictive control of a pasteurization pilot plant
    Sciendo, 2018
    Co-Authors: Pour Fatemeh Karimi, Puig Vicenç, Ocampo-martínez Carlos
    Abstract:

    This paper proposes two different health-aware economic predictive control strategies that aim at minimizing the damage of components in a pasteurization plant. The damage is assessed with a Rainflow-Counting algorithm that allows estimating the components’ fatigue. By using the results obtained from this algorithm, a simplified model that characterizes the health of the system is developed and integrated into the predictive controller. The overall control objective is modified by adding an extra criterion that takes into account the accumulated damage. The first strategy is a single-layer predictive controller with an integral action to eliminate the steady-state error that appears when adding the extra criterion. In order to achieve the best minimal accumulated damage and operational costs, the single-layer approach is improved with a multi-layer control scheme, where the solution of the dynamic optimization problem is obtained from the model in two different time scales. Finally, to achieve the advisable trade-off between minimal accumulated damage and operational costs, both control strategies are compared in simulation over a utility-scale pasteurization plant

  • Multi-layer health-aware economic predictive control of a pasteurization pilot plant
    'Walter de Gruyter GmbH', 2018
    Co-Authors: Karimi Pour Fatemeh, Puig Vicenç, Ocampo-martínez Carlos
    Abstract:

    This paper proposes two different health-aware economic predictive control strategies that aim at minimizing the damage of components in a pasteurization plant. The damage is assessed with a Rainflow-Counting algorithm that allows estimating the components’ fatigue. By using the results obtained from this algorithm, a simplified model that characterizes the health of the system is developed and integrated into the predictive controller. The overall control objective is modified by adding an extra criterion that takes into account the accumulated damage. The first strategy is a single-layer predictive controller with an integral action to eliminate the steady-state error that appears when adding the extra criterion. In order to achieve the best minimal accumulated damage and operational costs, the single-layer approach is improved with a multi-layer control scheme, where the solution of the dynamic optimization problem is obtained from the model in two different time scales. Finally, to achieve the advisable trade-off between minimal accumulated damage and operational costs, both control strategies are compared in simulation over a utility-scale pasteurization plant.This work has been partially funded by the Spanish Government (MINECO) through the project DEOCS (DPI2016-76493-C3-3-R), and by MINECO and FEDER through the project HARCRICS (DPI2014-58104-R).Peer reviewe

  • Output-feedback model predictive control of a pasteurization pilot plant based on an LPV model
    'IOP Publishing', 2016
    Co-Authors: Karimi Pour F., Ocampo-martínez Carlos, Puig Cayuela Vicenç
    Abstract:

    In order to optimize the trade-off between components life and energy consumption, the integration of a system health management and control modules is required. This paper proposes the integration of model predictive control (MPC) with a fatigue estimation approach that minimizes the damage of the components of a pasteurization plant. The fatigue estimation is assessed with the Rainflow Counting algorithm. Using data from this algorithm, a simplified model that characterizes the health of the system is developed and integrated with MPC. The MPC controller objective is modified by adding an extra criterion that takes into account the accumulated damage. But, a steady-state offset is created by adding this extra criterion. Finally, by including an integral action in the MPC controller, the steady-state error for regulation purpose is eliminated. The proposed control scheme is validated in simulation using a simulator of a utility-scale pasteurization plant.Peer Reviewe

Alessandro Cristofori - One of the best experts on this subject based on the ideXlab platform.

  • recent developments in frequency domain multi axial fatigue analysis
    International Journal of Fatigue, 2016
    Co-Authors: Denis Benasciutti, Frank Sherratt, Alessandro Cristofori
    Abstract:

    Abstract The purpose of this paper is to discuss the recent developments in multi-axial spectral methods, used for estimating fatigue damage of multi-axial random loadings from Power Spectral Density (PSD) data. The difference between time domain and frequency domain approaches in multi-axial fatigue is first addressed, the main advantages of frequency domain approach being pointed out. The paper then critically reviews some categories of multi-axial spectral methods: approaches based on uniaxial equivalent stress (strength criteria, “equivalent von Mises stress”, multi-axial Rainflow Counting), critical plane criteria (Matake, Carpinteri-Spagnoli, criterion based on resolved shear stress on critical plane), stress-invariants based criteria (Crossland, Sines, “Projection-by-Projection”). The “maximum variance” method and the Minimum Circumscribed Circle/Ellipse formulations defined in the frequency domain are also discussed. The paper critically analyses also non-proportional multi-axial loadings and the role of material fatigue parameters (e.g. S/N curves for bending/torsion) in relation to specific methods. The paper concludes with general comments on advantages and possible limitations in the use of multi-axial spectral methods, with special focus on the assumption of stationarity and Gaussianity in modelling multi-axial random loadings.

  • a stress invariant based criterion to estimate fatigue damage under multiaxial loading
    International Journal of Fatigue, 2008
    Co-Authors: Alessandro Cristofori, Luca Susmel, R Tovo
    Abstract:

    This paper summarises an attempt to propose a novel stress invariant based approach suitable for estimating fatigue damage in the presence of complex multiaxial fatigue loadings. In more detail, according to the devised method, fatigue damage is evaluated by studying the components of the deviator path projected along the axes of a convenient frame of reference, whose orientation univocally depends on the profile of the applied loading path. The Rainflow Counting method used in conjunction with the so-called modified Wohler curve method is subsequently employed to estimate the number of cycles to failure in the medium-cycle fatigue regime. The accuracy of the proposed approach was systematically checked by means of several experimental data taken from the literature and generated by testing different metallic materials under both in-phase and out-of-phase biaxial fatigue loading. This exercise allowed us to prove that the systematic application of the proposed approach resulted in highly accurate predictions and it held true independently of degree of multiaxiality of the stress field damaging the fatigue process zone.

J. Bahuaud - One of the best experts on this subject based on the ideXlab platform.

  • Standardization of the Rainflow Counting method for fatigue analysis
    International Journal of Fatigue, 1994
    Co-Authors: C Amzallag, J.p. Gerey, J. L. Robert, J. Bahuaud
    Abstract:

    Abstract The Rainflow procedure is a cycle-Counting method that makes it possible to store service measurements in a form suitable for fatigue analysis of structures: fatigue life prediction and simulation testing. A consultation has been conducted by the authors with different industries (automobile, aircraft, energy and steel) to obtain a consensus on a proposed Rainflow methodology and its use for fatigue analysis. An AFNOR document, resulting from this work, has been edited for describing the Rainflow procedure, the standardized presentation of results and the reconstruction of a loading sequence from a Rainflow matrix. This paper presents the methodology used and its application for combining different sequences.

R Tovo - One of the best experts on this subject based on the ideXlab platform.

  • a stress invariant based criterion to estimate fatigue damage under multiaxial loading
    International Journal of Fatigue, 2008
    Co-Authors: Alessandro Cristofori, Luca Susmel, R Tovo
    Abstract:

    This paper summarises an attempt to propose a novel stress invariant based approach suitable for estimating fatigue damage in the presence of complex multiaxial fatigue loadings. In more detail, according to the devised method, fatigue damage is evaluated by studying the components of the deviator path projected along the axes of a convenient frame of reference, whose orientation univocally depends on the profile of the applied loading path. The Rainflow Counting method used in conjunction with the so-called modified Wohler curve method is subsequently employed to estimate the number of cycles to failure in the medium-cycle fatigue regime. The accuracy of the proposed approach was systematically checked by means of several experimental data taken from the literature and generated by testing different metallic materials under both in-phase and out-of-phase biaxial fatigue loading. This exercise allowed us to prove that the systematic application of the proposed approach resulted in highly accurate predictions and it held true independently of degree of multiaxiality of the stress field damaging the fatigue process zone.

  • cycle distribution and fatigue damage under broad band random loading
    International Journal of Fatigue, 2002
    Co-Authors: R Tovo
    Abstract:

    Fatigue damage under broad-band loading is analysed by summarizing and reviewing available analytical solutions. Relationships between fatigue damage assessment and Counting methods are investigated by establishing when, in frequency domain analysis, analytical solutions of expected damage are connected with a Counting procedure assumption and how this is related to the Rainflow Counting procedure. A new approach is also proposed for Rainflow damage evaluation. This approach gives accurate approximations of fatigue damage under both broad- and narrow-band Gaussian loading; it is based on the theoretical investigation of possible combinations of peaks and valleys in Gaussian loading and on numerical fitting on several simulated broad-band loads.

Ying Min Low - One of the best experts on this subject based on the ideXlab platform.

  • uncertainty of the fatigue damage arising from a stochastic process with multiple frequency modes
    Probabilistic Engineering Mechanics, 2014
    Co-Authors: Ying Min Low
    Abstract:

    Abstract Predicting the variance of the fatigue damage due to a stochastic load process is a difficult classical problem that dates back to the 1960s. For many years, the available analytical methods for tackling this problem have been limited to the linear oscillator response under Gaussian white noise excitation. In a recent prior work, the author developed an improved method for calculating the damage variance for a general narrowband Gaussian process. From a fatigue uncertainty perspective, a narrowband process is particularly crucial as the amplitude correlation magnifies the variance. This paper extends the analysis to a multimodal process comprising two or more narrowband components. The proposed method is tractable, involving a single summation for an arbitrary spectral density. Moreover, closed form expressions are available for two special cases, i.e. the components are all linear oscillator responses or the spectral density of each is rectangular. The equations also yield insight on the multilayered correlation mechanisms produced by different narrowband components. The accuracy of the method is verified by Rainflow Counting of simulated time history stresses.

  • an analytical formulation for the fatigue damage skewness relating to a narrowband process
    Structural Safety, 2012
    Co-Authors: Ying Min Low
    Abstract:

    Abstract In spectral fatigue analysis, the expected fatigue damage is customarily used to ascertain the design fatigue life. The uncertainty of the damage induced by the underlying stochastic process is typically disregarded in both theory and practice. Yet, this uncertainty may be consequential in many circumstances. Recently, the author developed an accurate analytical approach for quantifying the damage variance for a narrowband Gaussian process. This paper extends the statistical analysis to the skewness, as the damage probability distribution can be distinctly asymmetric when the coefficient of variation is sizeable. For a linear oscillator system, the damage skewness has a closed form result, which is demonstrated to be highly accurate when benchmarked against Monte Carlo simulation and Rainflow Counting. For a more general narrowband process, two variants of the method are presented. The simpler version entails merely a single summation, whereas the more sophisticated approach involves a double summation that is still tractable. Further, it is shown that using the first three statistical moments, a good approximation to the distribution can be obtained.

  • variance of the fatigue damage due to a gaussian narrowband process
    Structural Safety, 2012
    Co-Authors: Ying Min Low
    Abstract:

    Abstract The fatigue life of a structure is inherently random when the loading is irregular. There is a vast body of literature on the analysis of the mean fatigue damage, but very few studies have been devoted to the variance. This paper presents an improved method for analyzing the variance of the damage for any narrowband Gaussian process. The field of application is not confined to the linear oscillator, unlike approaches in previous studies. The method is simple to apply; it involves a single summation for arbitrary processes, and closed form solutions are available for special cases (linear oscillator and bandpass process). The effectiveness of the method is demonstrated through case studies encompassing a variety of systems, including a realistic spectrum commonly seen in offshore engineering. Using Rainflow Counting of simulated time domain stresses as a benchmark, the proposed method is shown to yield a highly precise prediction of the variance. Moreover, it is significantly more accurate than an existing method for the linear oscillator system.

  • extending a time frequency domain hybrid method for riser fatigue analysis
    Applied Ocean Research, 2011
    Co-Authors: Ying Min Low
    Abstract:

    Abstract Fully coupled time domain analysis of a floating system is rigorous but time-consuming, thus an efficient hybrid method was developed in a prior work. The method simulates the coupled slow-drift responses in the time domain and analyzes the wave-frequency dynamics in the frequency domain. The hybrid method was shown to compare well with time domain analysis in predicting the mean-square vessel motions and line tensions. In this paper, the hybrid method is extended for the fatigue analysis of moorings and risers. The fatigue damage thus calculated is found to closely agree with the result from time domain analysis in conjunction with Rainflow Counting. Several spectral fatigue techniques are also compared, and these methods are significantly less accurate, thus attesting to the complexity of the problem.