A new Method to determine Stress Cycle Histograms of Structures under Gusty Wind Load
|
|
- Ashley Lawrence
- 5 years ago
- Views:
Transcription
1 new Method to determine Stress Cycle Histograms of Structures under Gusty Wind Load Fran H. Kemper Dept. for Wind Engineering, Institute for Steel Structures, RWTH achen University, 574 achen, Germany. bstract Based on spectral computations with a subsequent frequency based Rainflow count algorithm (Dirli method), a thorough investigation of the response behaviour and the associated Rainflow histograms has been performed for different strcutures under wind load. With respect to stress histograms over the lifetime, it has been identified that mainly the structural frequency and damping, as well as the shape coefficient of the Weibull distribution for the wind speed on site are relevant. Based on this conclusion, concerted calculations of various structural and site-related parameters have been performed. For each case, the Rainflow shape has been fitted to a quadratic logarithmic function. The associated quadratic and linear coefficients could finally be expressed based on the four main influence parameters dependent on structure and location. Summarized in surface plots, an easy to use method to determine the shape of the stress cycle count histogram for any structure and any location has been developed. Introduction For the structural safety of modern steel structures, a realistic consideration all quasi-static or dynamic cyclic actions, a correct interpretation of the resulting structural stresses, a meaningful damage cumulation approach and a realistic fatigue-related material resistance is needed. For structures under gusty wind load, the description of the stress cycles during the foreseen lifetime is often estimated based on simplified closed-form approaches. In most cases, these methods overestimate the Damage value significantly with increasing bandwith of the response process. In earlier investigations it has been shown, that detailed spectral structural computations in combination with a spectral Rainflow cycle count approach lead to reliable stress range distributions for arbitrary response bandwiths (Kemper & Feldmann, b). Spectral Computations of Stress Range Spectra The most common and accepted counting algorithm for cyclic stressed structures is the Rainflow method from Matsuishi & Endo (968). s this algorithm is based on a transient formulation a usage for stochastic wind load processes is limited to the field of Monte-Carlo Simulations with artificial time-series of the wind field. lot of efforts have been made to estimate Rainflow-lie distributions based on spectral densities of response processes, which is much more convinient for the treatment of stochastic fields. n overview of some current methods has been given from Halfpenny (). Own calculations showed, that Rainflow stress range spectra of gust excited structures can be determined in good agreement to
2 6 th European and frican Wind Engineering Conference transient methods based on an emprical formula from Dirli (985). lthough the computation succeeds much quicer than transient methods, for a general rating of structures or an implication into codes it still seems too complex. Especially in the field of mechanical engineering an empirical approach for estimating the Rainflow distribution based on the power spectral density is meanwhile well established. Dirli derived this method based on continuous random processes and subsequent numerical Rainflow counting Dirli (985). He discovered an empirical relationship between the frequency range description of the signal and the Rainflow distribution. His studies were directed to stationary, ergodic random processes with arbitrary bandwidth. Consistently, the Dirli probability density function of pea values of a process with any bandwidth is a weighted sum of a normal distribution and a Rayleigh distribution. In previous studies of Wirsching and Shehata?, a similar approach was chosen, but there an attempt was made to describe the Rainflow distributions by Weibull functions. The simulations of Dirli, as well as own simulations showed, that the Rainflow distributions of peas often differs significantly from a Weibull distribution. For this reason, the Wirsching-Factor, which has been used for instance from Holmes Holmes (), is not realistic in case of higher response bandwidth Kemper & Feldmann (a). With Dirli s formula, the density of the number of cycle counts N of a given stress level can be computed to: whereat: N () = E P T f D () () f D () = D Q e Z() Q + D Z() R e Z() R + D 3 Z() e Z() m () x m = m m R = γ x m D m m 4 γ D + D (3a) D = (x m γ ) + γ D = γ D + D R (3b) D 3 = D D Z() = m (3c) Q =.5 (γ D 3 D R) D are auxillary values. The accuracy of the method has been verified with respect to gust excited structures by comparing the results to corresponding transient simulations. In all cases, the discrepancies between transient Rainflow count and Dirli formula where negligible Kemper & Feldmann (b). Even geometrical nonlinear structures can be analyzed based on the presented spectral approach. The necessary stochastic description of the mechanical system has been presented in Kemper & Feldmann (c). The method presented in this paper is aimed to clarify the influence parameters on the stress range distribution for structures under gusty wind loads and to deduce a simplified approach which taes into account the most relevant influences. The stress range density over the lifetime T Life of a structure can be expressed as a convolution of the stress range spectra within a short reference period N(, u), e.g. T ref = min. at a given wind speed and the frequency of occurence of wind speeds f(u) at the considered site (Kemper & Feldmann, ): (3d)
3 6 th European and frican Wind Engineering Conference 3 Δσ Δσ max in % 5 β α Regression of Inverse N Δσ (N Life) = α log (N Life)+ β log(n Life)+ Δσ max Life -Function: N Life Δσ Δσ max ( ) Figure : Quadratic pproximation of the Inverse N Life -Function Δσ Δσ max Δσ m,8 8 Δσ uref Δσ m,i +.5 Δσ b m,7 7 Δσ m,6 6 N T Life () Life = N= f(u) i Δσ N N(, ( Δσ) dδσ u) du (4) life m,5 5 T ref Δσ m,i -.5 Δσ b Δσ m,4 4 It is meaningful Δσ b Δσ m,3 to decouple parameters which mainly affect the scale of the stress range amplitudes 3 (e.g. the reference Δσ m, wind speed on site) and those which affect the distribution as well (e.g. the structural frequency). s N () Life describes the density of cycle counts over the structural effects, a Δσ m, direct relation to the maximum amplitude 3 succeeds 4 based 5 on 6 the cumulative 7 8 stress N Life ( Δσ range ) distribution: σ σ max n example of,the N Life -function is given in Fig.. s a result of the cumulative representation,,5 N Life (/ max ) = / max σ σ Considering all parameters of the lan G. Davenport Wind Loading Chain, it can be stated, max N that mainly N Life the natural frequency of the structure and its damping behavior as well as the shape Life coefficient of the probability density function of the wind speed on site influence the distibution of stress range spectra. Based on systematic spectral computations, the regression parameter α and β of the general N Life - Curve (cp. Fig. ) have been determined, to identify the relations between the mentioned parameters and the shape of the Rainflow stress range cycle count. In order to extract the indiviual results of the performed computations to a simplified model, for each considered location (expressed by its Weibull parameters and ), a two-dimensional fit has been performed (cp. Fig. ). Finally, the surface regression coefficients (3 in case of a bilinear fit) have been determined. s a result, the shape of the Inverse N Life -Function, expressed by its coefficients α and β can be described related to the dynamical properties of the structure for any location: N Life (t) dt (5) the maximum stress range amplitude is located at N Life =, which corresponds to a probability of exceedance of p = /T Life. For a general usage, the amplitudes may be normalized to the maximum. 3 Influence Parameters and Model Simplification max (N g ) = (κ log f + κ log δ + κ 3 ) log N g... (λ log f + λ log δ + λ 3 ) log N g + (6)
4 6 th European and frican Wind Engineering Conference 4 NL Opt. α [:4.8 :.6] NL Opt. β [:4.8 :.6].5.5. f in Hz..δ. f in Hz..δ Figure : Regression of α and β dependent on the dynamic Properties of all considered Structures where κ i and λ i are the areal regression parameter of a bilinear approach, summarized in Fig. 3. The usage of the presented approach is quite simple:. Computation of the maximum stress amplitude max. Determination of auxiliary values κ i and λ i dependent on the location of the structure 3. Formulation of the cumulative Rainflow spectrum N Life dependent on the structural dynamic parameters with Eq. (6) The stress range density N Life (/ max) can be found to: N (s) = dn(s) ds N(s) = log(e) β 4 α + 4 s α Finally, stress range collectives can be derived for arbitrary class widths and the associated fatigue damage leads do: D = D L N Life ( () ) m + N D D D where: m and m describe the inclination of the structural S-N curve. 4 DMGE EQUIVLENCE FCTOR CONCEPT (7) N Life ( () ) m d (8) N D D In the preceding sections the main computation strategy and a simplified possibility for the determination of realistic cycle count distributions is presented. The latter allows a detailed verification of the actual fatigue life considering appropriate S-N curves and damage accumulation strategies. However, at least for a pre-design stage, the damage assessment might be still too extensive, as the damage integral has still to be solved. For this reason some additional considerations have been made, allowing to reduce the fatigue assessment to a really simple chec of the fatigue endurance. The following items are addressed in order to allow a further simplification: Consideration of a realistic shape of the N Life -curve based on α(f, δ,, ) and β(f, δ,, ) ssumption of a certain shape of the structural S-N curve (trilinear or single slope) Linear damage hypothesis (elementary or modified Miner rule)
5 6 th European and frican Wind Engineering Conference 5 κ κ κ λ λ λ Figure 3: Parameters κ and λ for the determination of realistic Rainflow stress range spectra under consideration of dynamic properties and wind speed probabilities Based on these preconditions, an equivalent stress amplitude E at a given number of cycles can be computed which leads to an identical damage than the original collective. The ratio between the maximum stress amplitude max and E, is therefore denoted as a damage equivalence factor. In order to calculate the damage due to the N Life cycle count distribution in a general form, the density of cycle numbers N Life (s) in accordance to Eq. (4) is needed. The deviation of the cumulative cycle count function is given by: where: N Life (s) = dn Life(s) ds = ln() [ γ(s) exp β + γ(s) ] ln() α (9) γ(s) = β 4 α + 4 s α s = / max The general formulation of the structural damage under consideration of the elementary Miner rule leads to: D = N Life () N c ( c ) m d () where c is the notch case of the structural detail and m ist the slope of the S-N curve. s the N Life curve represends the cumulative cycle counts within 5 years, Eq. () yields to the associated damage within this period.
6 6 th European and frican Wind Engineering Conference 6 4. Elementary Miner-Rule (acc. to Palmgren) In this section the steps are described, which allow the development of damage equivalence factors using the elementary Miner rule. The equivalent stress range E can be calculated implicitly by the definition of the number equivalent of cycles n E = N D = 5 6 and by the demand of an identity of damages: n E = N D! = D Miner,elementary () The associated stress range amplitude E is defined based on the structural S-N curve: E = ( ) D m ND m Under consideration of Eq. (), the equivalent stress amplitude can finally be derived to: E = N D N Life ( s max ) s m ds The damage equivalence factor K F for the consideration of the shape of the stress range collective is given by: m () (3) K F = max / E (4) The fatigue endurance verification can be performed considering characteristic values as follows: max /K F! D (5) realistic damage assessment is enabled using the bearable cycle counts, which are associated with the stress amplitude E : ( ) m D = N D (6) E Finally, the corresponding damage value is defined as: D = n E = N D (7) The verification now includes implicitly the individual shape of the stress and leads to the same collective damage value as the integral of the actual collective consideration based on Eq. (). 4. Damage Equivalence Factors for pplication For an enabling of a preferably simple and general fatigue assessment concept, it was essential to avoid dependencies of the damage equivalence factor K F to other parameters than the shape of the cycle count distribution. Especially an influence of the maximum stress amplitude max and the notch case C would complicate the concept. Considering Eq. (3), it becomes apparent that the equivalent stress range depends on the fatigue endurance limit D in a direct way and indirectly by the damage D. Therefore, the equivalent stress range E, and thus the damage equivalence factor K F, are not dependent on the notch case C. However, as soon as a S-N curve with different inclinations is used, this independency is lost, due to the necessary case distinction.
7 6th European and frican Wind Engineering Conference 7. d.. KF 4 b 6 8 = Determine KF via a or b lternatively a simplified determination via (Weibull), f and d is possible =.9. f. = a..4 Figure 4: Damage Equivalence Factors KF dependent on the regression parameter of the NLif e function and assuming the elementary Miner rule Generally, the maximum value of the stress collective max affects the computed structural damage. In case of a simple linear S-N curve (elementary Miner rule) it follows for different collective maximums max, and max, : max, m D = D (8) max, Consequently, in conjunction with equation (3) it follows, that the equivalent stress range E acts linear to the maximum stress amplitude max of the collective. Thus, the damage equivalence factor KF is also independent of the collective maximum amplitude max. When the modified Miner s rule is used, the damage equivalence factor KF depends on both the collective maximum and the notch case of the S-N curve. For the establishment of an easy concept it is therefore advantageous to use the conservative elementary Miner rule with a unique slope of m = 3. In Fig. 4, the damage equivalence factors are plotted for arbitrary combinations of the regression parameter α and β of the cycle count distribution NLif e. Considering the influence of wind characteristic and structural dynamic properties, the equivalent stress factors can be read directly from the chart. Therefore, the bi-linear regression model has been used. s the plot is restricted to three different values for the shape parameter of the Weibull distribution, the usage is limited to rather approximative calculations, for example as a part of a pre-dimensioning. For the accurate determination of the damage equivalent factors it is recommended to determine the parameter α and β in advance using the equations described in section 3. For the fatigue assessment finally Eq. (5) can be simplified to: γf f max! D KF γm f (9) Due to the implicit form of the elementary Miner rule this proof is generally on the safe side. The corresponding damage value can be calculated as follows: D= D KF max m ()
8 6 th European and frican Wind Engineering Conference 8 5 Conclusions The presented method allows for the determination of realistic Rainflow stress range distributions for structures under gusty wind load. The formulation taes into account the individual location of the structure by considering the frequency of occurrence of wind speeds, as well as the dynamical parameter of the structure. s main influencing parameters of the stress cycle count distribution, mainly the structural frequency, the damping behavior and the wind statistic on site has been identified. Under consideration of appropriate shape function, the four independent parameters have been brought together in order to enable a simplified, graphical description. Finally, the damage equivalence factor concepts has been introduced on the base of the regression parameters which describe the actual shape of the cycle count distribution. In combination with the elementary Miner rule it was possible to calculated divisors, which allow a reduction of the maximum stress level in order to consider the distribution of cycle counts. References Dirli, T pplication of computers to fatigue analysis. Ph.D. thesis, Warwic University, Warwic. Halfpenny, ndrew.. Rainflow Cycle Counting and coustic Fatigue nalysis Techniques for Random Loading. In: RSD. Holmes, J. D.. Wind loading of structures. London and New Yor: Spon Press. Kemper, F. H., & Feldmann, M.. Rating of the fatigue relevance of gust induced vibrations based on spectral methods. Pages of: Proceedings of the 9th UK Conference on Wind Engineering. Lulu.com. Kemper, F. H., & Feldmann, M. a. ppraisement of Fatigue Phenomena due to Gust induced Vibrations based on closed-form pproaches. In: ICWE 3. Kemper, F. H., & Feldmann, M. b. Fatigue life prognosis for structural elements under stochastic wind loading based on spectral methods: Part : Linear structures. In: EURODYN. Kemper, F. H., & Feldmann, M. c. Fatigue life prognosis for structural elements under stochastic wind loading based on spectral methods: Part : Nonlinear structures. In: EURODYN. Matsuishi, M., & Endo, T Fatigue of metals subjected to varying stress. Japan Society of Mechanical Engineers.
Gust-induced fatigue cycle counts - sensitivity to dynamic response, wind climate and direction
Gust-induced fatigue cycle counts - sensitivity to dynamic response, wind climate and direction Frank H. Kemper ) and John D. Holmes ) ) Institute for Steel Structures, RWTH Aachen University, 574 Aachen,
More informationOptimized PSD Envelope for Nonstationary Vibration
Optimized PSD Envelope for Nonstationary Vibration Tom Irvine Dynamic Concepts, Inc NASA Engineering & Safety Center (NESC) 3-5 June 2014 The Aerospace Corporation 2010 The Aerospace Corporation 2012 Vibrationdata
More informationOptimized PSD Envelope for Nonstationary Vibration Revision A
ACCEL (G) Optimized PSD Envelope for Nonstationary Vibration Revision A By Tom Irvine Email: tom@vibrationdata.com July, 014 10 FLIGHT ACCELEROMETER DATA - SUBORBITAL LAUNCH VEHICLE 5 0-5 -10-5 0 5 10
More informationStress Concentrations, Fatigue, Fracture
Stress Concentrations, Fatigue, Fracture The fundamental topic in this document is the development of cracks in steel. For structures subjected to cyclic loads, such cracks can develop over time and ultimately
More informationThe Introduction of Pro-EMFATIC For Femap
Che-Wei L. Chang PhD The Introduction of Pro-EMFATIC For Femap Femap Symposium 2014 May 14-16, Atlanta, GA, USA FEMAP SYMPOSIUM 2014 Discover New Insights Table of Contents What Is Pro-EMFATIC? What Is
More informationA USER-FRIENDLY TOOL FOR FATIGUE ASSESSMENT OF STEEL STRUCTURES ACCORDING TO EUROCODE 3
Proceedings of the 5th International Conference on Integrity-Reliability-Failure, Porto/Portugal 24-28 July 2016 Editors J.F. Silva Gomes and S.A. Meguid Publ. INEGI/FEUP (2016) PAPER REF: 6274 A USER-FRIENDLY
More informationD. Benasciutti a, R. Tovo b
«A COMPREHENSIVE APPROACH TO FATIGUE UNDER RANDOM LOADING: non-gaussian and non-stationary loading investigations» D. Benasciutti a, R. Tovo b a DIEGM, Dipartimento di Ingegneria Elettrica Gestionale Meccanica,
More informationPROBLEMS OF EQUIVALENT LOAD AMPLITUDE IN FATIGUE LIFE CALCULATIONS
POLISH MARITIME RESEARCH 1(89) 2016 Vol. 23; pp. 85-92 10.1515/pomr-2016-0012 PROBLEMS OF EQUIVALENT LOAD AMPLITUDE IN FATIGUE LIFE CALCULATIONS Bogdan Ligaj, Assoc. Prof. Robert Sołtysiak, Ph. D. University
More informationScienceDirect. Fatigue life from sine-on-random excitations
Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 101 (2015 ) 235 242 3rd International Conference on Material and Component Performance under Variable Amplitude Loading, VAL2015
More informationRandom Fatigue. ! Module 3. ! Lecture 23 :Random Vibrations & Failure Analysis
!! Module 3! Lecture 23 :Random Vibrations & Failure Analysis Random Fatigue!! Sayan Gupta Department of Applied Mechanics Indian Institute of Technology Madras Random fatigue As has been mentioned earlier,
More informationASME 2013 IDETC/CIE 2013 Paper number: DETC A DESIGN ORIENTED RELIABILITY METHODOLOGY FOR FATIGUE LIFE UNDER STOCHASTIC LOADINGS
ASME 2013 IDETC/CIE 2013 Paper number: DETC2013-12033 A DESIGN ORIENTED RELIABILITY METHODOLOGY FOR FATIGUE LIFE UNDER STOCHASTIC LOADINGS Zhen Hu, Xiaoping Du Department of Mechanical & Aerospace Engineering
More informationFatigue Damage Spectrum calculation in a Mission Synthesis procedure for Sine-on-Random excitations
Journal of Physics: Conference Series PAPER OPEN ACCESS Fatigue Damage Spectrum calculation in a Mission Synthesis procedure for Sine-on-Random excitations Related content - A new compound control method
More informationNTNU Faculty of Engineering Science and Technology Department of Marine Technology TMR 4195 DESIGN OF OFFSHORE STRUCTURES
NTNU Faculty of Engineering Science and Technology Department of Marine Technology EXERCISE 4 TMR 495 DESIGN OF OFFSHORE STRUCTURES Distr. Date: 9 th Feb 4 Sign: Q. Chen Mandatory Exercise This exercise
More informationRapid Earthquake Loss Assessment: Stochastic Modelling and an Example of Cyclic Fatigue Damage from Christchurch, New Zealand
Rapid Earthquake Loss Assessment: Stochastic Modelling and an Example of Cyclic Fatigue Damage from Christchurch, New Zealand John B. Mander 1 and Geoffrey W. Rodgers 2, David Whittaker 3 1 University
More informationVibration based Fatigue Damage Assessment of Cantilever Beams
5 th National Conference on Machines and Mechanisms NaCoMM-8 Vibration based Fatigue Damage Assessment of Cantilever Beams N. Harish Chandra, A.S. Sekhar Abstract This paper explores to relate total fatigue
More informationVibration Fatigue Analysis in MSC.NASTRAN
Vibration Fatigue Analysis in MSC.NASTRAN JULY 2011 MAVERICK UNITED CONSULTING ENGINEERS TABLE OF CONTENTS ACKNOWLEDGEMENTS... 3 1.1 GL, ML VIBRATION FATIGUE ANALYSIS... 4 1.1.1 Maximum Absolute Principal
More informationFrequency Based Fatigue
Frequency Based Fatigue Professor Darrell F. Socie Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign 001-01 Darrell Socie, All Rights Reserved Deterministic versus
More informationA Sample Durability Study of a Circuit Board under Random Vibration and Design Optimization
A Sample Durability Study of a Circuit Board under Random Vibration and Design Optimization By: MS.ME Ahmad A. Abbas Ahmad.Abbas@AdvancedCAE.com www.advancedcae.com Sunday, March 07, 2010 Advanced CAE
More informationRandom Variables. Gust and Maneuver Loads
Random Variables An overview of the random variables was presented in Table 1 from Load and Stress Spectrum Generation document. Further details for each random variable are given below. Gust and Maneuver
More informationNumerical methods of multiaxial fatigue life prediction for elastomers under variable amplitude loadings
ORIGINAL CONTRIBUTION doi: 10.1111/ffe.12401 Numerical methods of multiaxial fatigue life prediction for elastomers under variable amplitude loadings J. CHUNG and N. H. KIM Department of Mechanical and
More informationLoad Determination. Fatigue Life Predictions Infinite Life, Stress Life, Strain Life
Durability Agenda Durability Basics Fatigue, Stress, Strain Load Determination Measurements, Multi-Body Simulation Loads and Damage S-N Curve, Cycle Counting Load Characterization Establishing Durability
More informationAnalysis Handbook. Metal Fatigue. for Computer-Aided Engineering. Barkey. Yung-Li Lee. Practical Problem-Solving Techniques. Hong-Tae Kang. Mark E.
Metal Fatigue Analysis Handbook Practical Problem-Solving Techniques for Computer-Aided Engineering Yung-Li Lee Mark E. Barkey Hong-Tae Kang ms- ELSEVIER AMSTERDAM BOSTON HEIDELBERG LONDON NEW YORK OXFORD
More informationA probabilistic method to predict fatigue crack initiation
International Journal of Fracture (2006) 137:9 17 DOI 10.1007/s10704-005-3074-0 Springer 2006 A probabilistic method to predict fatigue crack initiation SALIL. S. KULKARNI, L. SUN, B. MORAN, S. KRISHNASWAMY
More informationKliment Ohridski Blvd No 10, 1756 Sofia, Bulgaria; Fax:
Multiaxial Fatigue Life Assessment of Components of Forged Steel Ck 45 (SAE 1045) and of Sintered Steel Fe-1.5Cu by Integration of Damage Differentials (IDD) S. H. Stefanov 1, C. M. Sonsino 1 Department
More information2028. Life estimation of the beam with normal distribution parameters and subjected to cyclic load
2028. Life estimation of the beam with normal distribution parameters and subjected to cyclic load Changyou Li 1, Xuchu Wang 2, Wei Wang 3, Yimin Zhang 4, Song Guo 5 1, 2, 3, 4 School of Mechanical Engineering
More informationFatigue Reliability and Effective Turbulence Models in Wind Farms
Downloaded from vbn.aau.dk on: marts 28, 2019 Aalborg Universitet Fatigue Reliability and Effective Turbulence Models in Wind Farms Sørensen, John Dalsgaard; Frandsen, S.; Tarp-Johansen, N.J. Published
More informationPROBABILITY-BASED DESIGN EARTHQUAKE LOAD CONSIDERING ACTIVE FAULT
PROBABILITY-BASED DESIGN EARTHUAKE LOAD CONSIDERING ACTIVE FAULT Jun KANDA And Ichiro SATOH SUMMARY The probability-based structural design can provide a specific safety performance demand for the earthquake
More informationNONLINEAR STATIC AND MULTI-AXIAL FATIGUE ANALYSIS OF AUTOMOTIVE LOWER CONTROL ARM USING NEiNASTRAN
NONLINEAR STATIC AND MULTI-AXIAL FATIGUE ANALYSIS OF AUTOMOTIVE LOWER CONTROL ARM USING NEiNASTRAN Dr. J.M. Mahishi, Director Engineering MS&M Engineering Inc, Farmington Hills, MI, USA SUMMARY The Lower
More informationHowever, reliability analysis is not limited to calculation of the probability of failure.
Probabilistic Analysis probabilistic analysis methods, including the first and second-order reliability methods, Monte Carlo simulation, Importance sampling, Latin Hypercube sampling, and stochastic expansions
More informationLoad and Stress Spectrum Generation
Load and Stress Spectrum Generation During 1962, at the request of the FAA, and upon recommendation of the National Aeronautics and Space Administration (NASA) Committee on Aircraft Operating Problems,
More informationPredicting Fatigue Life with ANSYS Workbench
Predicting Fatigue Life with ANSYS Workbench How To Design Products That Meet Their Intended Design Life Requirements Raymond L. Browell, P. E. Product Manager New Technologies ANSYS, Inc. Al Hancq Development
More informationRandom Vibrations & Failure Analysis Sayan Gupta Indian Institute of Technology Madras
Random Vibrations & Failure Analysis Sayan Gupta Indian Institute of Technology Madras Lecture 1: Introduction Course Objectives: The focus of this course is on gaining understanding on how to make an
More informationVolume 2 Fatigue Theory Reference Manual
Volume Fatigue Theory Reference Manual Contents 1 Introduction to fatigue 1.1 Introduction... 1-1 1. Description of the applied loading... 1-1.3 Endurance curves... 1-3 1.4 Generalising fatigue data...
More informationKul Aircraft Structural Design (4 cr) Fatigue Analyses
Kul-34.4300 Aircraft Structural Design (4 cr) M Kanerva 2016 Objective and Contents of the Module The objective of the module is to describe (1) how aircraft fatigue analyses are performed and (2) how
More informationRules for Classification and Construction Analysis Techniques
V Rules for Classification and Construction Analysis Techniques 1 Hull Structural Design Analyses 2 Guidelines for Fatigue Strength Analyses of Ship Structures Edition 2004 The following Guidelines come
More informationAutomotive CAE Durability Analysis Using Random Vibration Approach
utomotive CE Durability nalysis Using Random Vibration pproach Hong Su, Ph.D. CE Tools and Methods Group dvanced Technology Office, Visteon Corporation bstract Dynamic road loads to automotive structures
More informationLoad-strength Dynamic Interaction Principle and Failure Rate Model
International Journal of Performability Engineering Vol. 6, No. 3, May 21, pp. 25-214. RAMS Consultants Printed in India Load-strength Dynamic Interaction Principle and Failure Rate Model LIYANG XIE and
More informationNumerical simulation of an overhead power line section under wind excitation using wind tunnel test results and in-situ measured data
Proceedings of the 9th International Conference on Structural Dynamics, EURODYN 214 Porto, Portugal, 3 June - 2 July 214 A. Cunha, E. Caetano, P. Ribeiro, G. Müller (eds.) ISSN: 2311-92; ISBN: 978-972-752-165-4
More information2 nd SDWED Symposium Advances in Modelling of Wave Energy Devices - WP4
2 nd SDWED Symposium Advances in Modelling of Wave Energy Devices - WP4 Andrew Zurkinden Wave Energy Research Group, Civil Engineering Department, Aalborg University, Denmark April 26, 212 Structural Design
More informationSPECTRUM FATIGUE LIFETIME AND RESIDUAL STRENGTH FOR FIBERGLASS LAMINATES IN TENSION
AIAA-2-25 SPECTRUM FATIGUE LIFETIME AND RESIDUAL STRENGTH FOR FIBERGLASS LAMINATES IN TENSION Neil Wahl Montana Tech of The University of Montana Butte, Montana 597 Daniel Samborsky John Mandell Douglas
More informationRolling Contact Fatigue Life Test Design and Result Interpretation Methods Maintaining Compatibility of Efficiency and Reliability
Rolling Contact Fatigue Life Test Design and Result Interpretation Methods Maintaining Compatibility of Efficiency and Reliability Takumi FUJITA L 1 L 5 L 1 L 5 L 1 L 5 L 1 L 1 L 1 L 5 In this report,
More informationThermodynamics of nuclei in thermal contact
Thermodynamics of nuclei in thermal contact Karl-Heinz Schmidt, Beatriz Jurado CENBG, CNRS/IN2P3, Chemin du Solarium B.P. 120, 33175 Gradignan, France Abstract: The behaviour of a di-nuclear system in
More informationFatigue Life. The curve may be plotted as semilogarithmic
Fatigue Life The total number of cycles for which a specimen sustains before failure is called fatigue (cyclic) life, denoted by N. The graph by plotting values of S a and N is called S-N curve or Wöhler
More informationFrequency-domain methods for a vibration-fatigue-life estimation - Application to real data
Frequency-domain methods for a vibration-fatigue-life estimation - Application to real data Matjaž Mršnik, Janko Slavič, Miha Boltežar Faculty of Mechanical Engineering, University of Ljubljana, Slovenia
More informationSMA Technical Memorandum 121
SMA Technical Memorandum 121 Title: Some thoughts on the SGH test data on NYTEX tubes Date: 2 7 February 1998 (draft) 15 May 1998 (final) From: Jim Moran Although the cyclic testing and pull-to-failure
More informationDamage accumulation model for aluminium-closed cell foams subjected to fully reversed cyclic loading
Fatigue & Fracture of Engineering Materials & Structures doi: 10.1111/j.1460-2695.2011.01591.x Damage accumulation model for aluminium-closed cell foams subjected to fully reversed cyclic loading H. PINTO
More informationFatigue Life Assessment of 30CrNiMo8HH Steel Under Variable Amplitude Loading
Fatigue Life Assessment of 3CrNiMo8HH Steel Under Variable Amplitude Loading by Elfaitori Ibrahim A thesis presented to the University of Waterloo in fulfillment of the thesis requirement for the degree
More informationPSD Analysis and Optimization of 2500hp Shale Gas Fracturing Truck Chassis Frame
Send Orders for Reprints to reprints@benthamscience.ae The Open Mechanical Engineering Journal, 2014, 8, 533-538 533 Open Access PSD Analysis and Optimization of 2500hp Shale Gas Fracturing Truck Chassis
More informationModel-Assisted Probability of Detection for Ultrasonic Structural Health Monitoring
4th European-American Workshop on Reliability of NDE - Th.2.A.2 Model-Assisted Probability of Detection for Ultrasonic Structural Health Monitoring Adam C. COBB and Jay FISHER, Southwest Research Institute,
More informationProbabilistic Fatigue and Damage Tolerance Analysis for General Aviation
Probabilistic Fatigue and Damage Tolerance Analysis for General Aviation Probabilistic fatigue and damage tolerance tool for the Federal Aviation Administration to perform risk analysis Juan D. Ocampo
More informationBuffeting research of suspension steel frame for ±500 kv converter station DC filter
Buffeting research of suspension steel frame for ±5 kv converter station DC filter Long-Yi Ou 1, Yang-Ke Jian 2 State Grid Hunan Electric Power Corporation Research Institute, Changsha 417, China 2 Corresponding
More informationFREQENCY DOMAIN FATIGUE ANALYSIS
FREQENCY DOMAIN FATIGUE ANALYSIS Peter Bigoš, Peter Bocko 1 Key words: frequency domain analysis, vibration fatigue, wind loading 1 INTRODUCTION Dynamical loading is a dominant factor causing the fatigue
More informationOutline of parts 1 and 2
to Harmonic Loading http://intranet.dica.polimi.it/people/boffi-giacomo Dipartimento di Ingegneria Civile Ambientale e Territoriale Politecnico di Milano March, 6 Outline of parts and of an Oscillator
More informationA Novel Model-Based Algorithm for Battery Prognosis
A Novel Model-Based Algorithm for Battery Prognosis Lorenzo Serrao Simona Onori Giorgio Rizzoni Yann Guezennec The Ohio State University, Department of Mechanical Engineering and Center for Automotive
More informationModal Based Fatigue Monitoring of Steel Structures
Modal Based Fatigue Monitoring of Steel Structures Jesper Graugaard-Jensen Structural Vibration Solutions A/S, Denmark Rune Brincker Department of Building Technology and Structural Engineering Aalborg
More informationModelling trends in the ocean wave climate for dimensioning of ships
Modelling trends in the ocean wave climate for dimensioning of ships STK1100 lecture, University of Oslo Erik Vanem Motivation and background 2 Ocean waves and maritime safety Ships and other marine structures
More informationThis guide is made for non-experienced FEA users. It provides basic knowledge needed to start your fatigue calculations quickly.
Quick Fatigue Analysis Guide This guide is made for non-experienced FEA users. It provides basic knowledge needed to start your fatigue calculations quickly. Experienced FEA analysts can also use this
More informationCyclic Event Identification and Fatigue Damage Assessment for Multiaxial Mission Loadings
Cyclic Event Identification and Fatigue Damage Assessment for Multiaxial Mission Loadings Mr. Eric Goodin 1, Dr. Alan Kallmeyer 1, and Dr. Peter Kurath 2 1 Department of Mechanical Engineering, North Dakota
More informationDevelopment of a Modal Approach for the Fatigue Damage Evaluation of Mechanical Components Subjected to Random Loads
Copyright 2012 Tech Science Press SDHM, vol.8, no.1, pp.1-29, 2012 Development of a Modal Approach for the Fatigue Damage Evaluation of Mechanical Components Subjected to Random Loads F.Cianetti 1 Abstract:
More informationTOOLS FOR A MULTIAXIAL FATIGUE ANALYSIS OF STRUCTURES SUBMITTED TO RANDOM VIBRATIONS
1 TOOLS FOR A MULTIAXIAL FATIGUE ANALYSIS OF STRUCTURES SUBMITTED TO RANDOM VIBRATIONS X.Pitoiset, A.Preumont Active Structures Laboratory, ULB - CP 165/42 Av F.D. Roosevelt 50, B-1050 Brussels Mail: scmero@ulb.ac.be,
More informationTMHL TMHL (Del I, teori; 1 p.) SOLUTION I. II.. III. Fig. 1.1
TMHL6 204-08-30 (Del I, teori; p.). Fig.. shows three cases of sharp cracks in a sheet of metal. In all three cases, the sheet is assumed to be very large in comparison with the crack. Note the different
More informationStructures and Multiaxial Fatigue Analysis. Timothy Langlais
Computational Methods for Multiaxial Fatigue 1 Structures and Multiaxial Fatigue Analysis Timothy Langlais University of Minnesota langlais@me.umn.edu Advisers: J. H. Vogel and T. R. Chase http://www.menet.umn.edu/
More informationReliability of Acceptance Criteria in Nonlinear Response History Analysis of Tall Buildings
Reliability of Acceptance Criteria in Nonlinear Response History Analysis of Tall Buildings M.M. Talaat, PhD, PE Senior Staff - Simpson Gumpertz & Heger Inc Adjunct Assistant Professor - Cairo University
More informationMODIFIED MONTE CARLO WITH LATIN HYPERCUBE METHOD
MODIFIED MONTE CARLO WITH LATIN HYPERCUBE METHOD Latin hypercube sampling (LHS) was introduced by McKay, Conover and Beckman as a solution to increase the efficiency of computer simulations. This technique
More informationImproving the Accuracy of Dynamic Vibration Fatigue Simulation
Improving the Accuracy of Dynamic Vibration Fatigue Simulation Kurt Munson HBM Prenscia Agenda 2 1. Introduction 2. Dynamics and the frequency response function (FRF) 3. Using finite element analysis (FEA)
More informationArmin Rasch * Abstract
Optimization strategy for the identification of elastomer parameters of truck mountings for the improved adjustment of Multi-Body Simulation data with measured values on rough road conditions Armin Rasch
More informationNONLINEAR RANDOM DISPLACEMENT AND FATIGUE ESTIMATES USING PDF TRANSFORMATIONS
NONLINEAR RANDOM DISPLACEMENT AND FATIGUE ESTIMATES USING PDF TRANSFORMATIONS K. A. Sweitzer and N. S. Ferguson ITT Industries Space Systems Division LLC, Rochester, NY, USA Institute of Sound and Vibration
More informationVariation of Stress Range Due to Variation in Sea States An Overview of Simplified Method of Fatigue Analysis of Fixed Jacket Offshore Structure
American Journal of Engineering Research (AJER) e-issn : 2320-0847 p-issn : 2320-0936 Volume-03, Issue-04, pp-98-107 www.ajer.org Research Paper Open Access Variation of Due to Variation in Sea States
More informationFatigue Reliability and Calibration of Fatigue Design Factors for Offshore Wind Turbines
Energies 2012, 5, 1816-1834; doi:10.3390/en5061816 Article OPEN ACCESS energies ISSN 1996-1073 www.mdpi.com/journal/energies Fatigue Reliability and Calibration of Fatigue Design Factors for Offshore Wind
More informationModule 8. Lecture 5: Reliability analysis
Lecture 5: Reliability analysis Reliability It is defined as the probability of non-failure, p s, at which the resistance of the system exceeds the load; where P() denotes the probability. The failure
More informationLoad Sequence Interaction Effects in Structural Durability
Load Sequence Interaction Effects in Structural Durability M. Vormwald 25. Oktober 200 Technische Universität Darmstadt Fachgebiet Werkstoffmechanik Introduction S, S [ log] S constant amplitude S variable
More informationAvailable online at ScienceDirect. Procedia Engineering 133 (2015 ) th Fatigue Design conference, Fatigue Design 2015
Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 133 (2015 ) 613 621 6th Fatigue Design conference, Fatigue Design 2015 Response Spectra and Expected Fatigue Reliability: A
More informationAlternate Methods for Construction of Design Response Spectrum
Proc. Natl. Sci. Counc. ROC(A) Vol. 22, No. 6, 1998. pp. 775-782 Alternate Methods for Construction of Design Response Spectrum R. YAUNCHAN TAN Department of Civil Engineering National Taiwan University
More informationFatigue Modeling of Large Composite Wind Turbine Blades
Fatigue Modeling of Large Composite Wind Turbine Blades Oscar Castro K. Branner, P. Brøndsted, N. Dimitrov, P. Haselbach 4th Durability and Fatigue Advances in Wind, Wave and Tidal Energy. Bristol, UK
More informationNEW CONCEPT OF A LOCAL ELASTIC STRESS APPROACH FOR FATIGUE LIFE CALCULATION
NEW CONCEPT OF A LOCAL ELASTIC STRESS APPROACH FOR FATIGUE LIFE CALCULATION * Milan Ruzicka Jan Papuga Abstract: Principles of different approaches to fatigue life prediction until the crack initiation
More informationReliability Considerations for Steel Frames Designed with Advanced Analysis
Reliability Considerations for Steel Frames Designed with Advanced Analysis Stephen G. Buonopane Benjamin W. Schafer Takeru Igusa Dept. of Civil Engineering Johns Hopkins University Features of Advanced
More informationStress concentrations, fracture and fatigue
Stress concentrations, fracture and fatigue Piet Schreurs Department of Mechanical Engineering Eindhoven University of Technology http://www.mate.tue.nl/ piet December 1, 2016 Overview Stress concentrations
More informationApplication of Capacity Spectrum Method to timber houses considering shear deformation of horizontal frames
Application of Capacity Spectrum Method to timber houses considering shear deformation of horizontal frames Kawai, N. 1 ABSTRACT Relating to the revision of Building Standard Law of Japan, the application
More informationChapter 6 Seismic Design of Bridges. Kazuhiko Kawashima Tokyo Institute of Technology
Chapter 6 Seismic Design of Bridges Kazuhiko Kawashima okyo Institute of echnology Seismic Design Loading environment (dead, live, wind, earthquake etc) Performance criteria for gravity (deflection, stresses)
More informationProbabilistic Assessment of a Stiffened Carbon Fibre Composite Panel Operating in its Postbuckled Region Authors: Correspondence:
Probabilistic Assessment of a Stiffened Carbon Fibre Composite Panel Operating in its Postbuckled Region Authors: D. Elder and R. Thomson Cooperative Research Centre for Advanced Composite Structures Limited
More informationACCELERATED ELECTRICAL AND MECHANICAL AGEING TESTS OF HIGH TEMPERATURE LOW SAG (HTLS) CONDUCTORS
27-April-7 ACCELERATED ELECTRICAL AND MECHANICAL AGEING TESTS OF HIGH TEMPERATURE LOW SAG (HTLS) CONDUCTORS Dominik Stengel, Richard Bardl (BAM) Christian Kühnel, Steffen Großmann (TU Dresden) Wilhelm
More informationVibrations of Chimneys under the Action of the Wind
Porto, Portugal, 3 June - 2 July 214 A. Cunha, E. Caetano, P. Ribeiro, G. Müller (eds.) ISSN: 2311-92; ISBN: 978-972-752-165-4 Vibrations of Chimneys under the Action of the Wind Hans-Jürgen Niemann 1,
More informationInstitute for Statics und Dynamics of Structures Fuzzy probabilistic safety assessment
Institute for Statics und Dynamics of Structures Fuzzy probabilistic safety assessment Bernd Möller Fuzzy probabilistic safety assessment randomness fuzzy randomness fuzzyness failure Fuzzy- Probabilistik
More informationTENSILE FATIGUE BEHAVIOR OF SINGLE FIBRES AND FIBRE BUNDLES
TENSILE FATIGUE BEHAVIOR OF SINGLE FIBRES AND FIBRE BUNDLES C. Qian 1 *, R. P. L. Nijssen 1, D. D. Samborsky 2, C.Kassapoglou 3, Z. Gürdal 3, G. Q. Zhang 4 1 Knowledge Centre Wind turbine Materials and
More informationAvailable online at ScienceDirect. Procedia Engineering 133 (2015 ) th Fatigue Design conference, Fatigue Design 2015
Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 133 (015 ) 698 713 6th Fatigue Design conference, Fatigue Design 015 Fatigue life from kurtosis controlled excitations Frédéric
More informationMARKOV CHAIN APPLICATION IN FATIGUE RELIABILITY ANALYSIS FOR DURABILITY ASSESSMENT OF A VEHICLE CRANKSHAFT
MARKOV CHAIN APPLICATION IN FATIGUE RELIABILITY ANALYSIS FOR DURABILITY ASSESSMENT OF A VEHICLE CRANKSHAFT S. S. K.Singh,2, S. Abdullah 2 and N. A. N.Mohamed 3 Centre of Technology Marine Engineering,
More informationProbabilistic approach for the fatigue design of tower cranes
Probabilistic approach for the fatigue design of tower cranes S. Bucas a,b,c, P. Rumelhart c, N. Gayton a,b, A. Chateauneuf a,b a. Clermont Université, Université Blaise Pascal, IFMA, Institut Pascal,
More information5.5 Exercises for This Chapter Two-Axle Vehicle on Cosine Track Two-Axle Vehicle on Generally Periodic Track...
Contents 1 Introduction... 1 1.1 The Basic Function of the Wheel/rail System.... 1 1.2 Significance of Dynamics on the Operation of Rail Vehicles... 2 1.3 On the History of Research in the Field of Railway
More informationReduction of computational cost for design of wind turbine tower against fatigue failure
No. E-13-AAA- Reduction of computational cost for design of wind turbine tower against fatigue failure Ali R. Fathi, Hamid R. Lari, Abbas Elahi Wind turbine Technology Development Center Niroo Research
More informationEFFECT OF ALTERNATE CHANGE IN STRESS RATIO ON FATIGUE STRENGTH OF WOVEN FABRIC CFRP LAMINATE AND LIFE PREDICTION USING THE ANISOMORPHIC CFL DIAGRAM
EFFECT OF ALTERNATE CHANGE IN STRESS RATIO ON FATIGUE STRENGTH OF WOVEN FABRIC CFRP LAMINATE AND LIFE PREDICTION USING THE ANISOMORPHIC CFL DIAGRAM M. Kawai a*, K. Yang a, S. Oh a a Department of Engineering
More informationCharacterization and modelling of seismic action
COST C26: Urban Habitat Constructions under Catastrophic Events Final Conference, 16-18 September 2010, Naples, Italy Characterization and modelling of seismic action Report of WG2: Earthquake resistance
More informationFundamentals of Durability. Unrestricted Siemens AG 2013 All rights reserved. Siemens PLM Software
Fundamentals of Durability Page 1 Your single provider of solutions System simulation solutions 3D simulation solutions Test-based engineering solutions Engineering services - Deployment services Troubleshooting
More informationLoad-Strength Interference
Load-Strength Interference Loads vary, strengths vary, and reliability usually declines for mechanical systems, electronic systems, and electrical systems. The cause of failures is a load-strength interference
More informationFatigue-Ratcheting Study of Pressurized Piping System under Seismic Load
Fatigue-Ratcheting Study of Pressurized Piping System under Seismic Load A. Ravi Kiran, M. K. Agrawal, G. R. Reddy, R. K. Singh, K. K. Vaze, A. K. Ghosh and H. S. Kushwaha Reactor Safety Division, Bhabha
More informationSITE ANALYSIS USING RANDOM VIBRATION THEORY
Transactions, SMiRT-23, Paper ID 050 SITE ANALYSIS USING RANDOM VIBRATION THEORY 1 President APA Consulting, USA Alejandro P. Asfura 1 ABSTRACT This paper compares two methods for the seismic analysis
More informationAvailable online at ScienceDirect. Procedia Engineering 74 (2014 )
Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 74 (2014 ) 236 241 XV11 International Colloquim on Mechanical Fatigue of Metals (ICMFM17) ProFatigue: A software program for
More informationFatigue Life Estimation of an Aircaft Engine Under Different Load Spectrums
Int. J. Turbo Jet-Engines, Vol. 29 (2012), 259 267 Copyright 2012 De Gruyter. DOI 10.1515/tjj-2012-0017 Fatigue Life Estimation of an Aircaft Engine Under Different Load Spectrums Hong-Zhong Huang, 1;
More informationCritical Plane Approach to Multiaxial Variable Amplitude Fatigue Loading
Critical Plane Approach to Multiaxial Variable Amplitude Fatigue Loading Yingyu Wang Key Laboratory of Fundamental Science for National Defense-Advanced Design Technology of Flight Vehicle, Nanjing University
More informationPaper to be presented at Americas User Conference, Oct 5-9, Sheraton Universal Hotel, Universal City, California
Paper to be presented at Americas User Conference, Oct 5-9, Sheraton Universal Hotel, Universal City, California Title: Vibration Fatigue Analysis in the Finite Element Environment Authors: Dr Neil Bishop,
More informationS. Stefanov 1, J. Wiebesiek 2, K. Störzel 2, T. Bruder 2
Fatigue Life Assessment of Laserbeam Welded Steel Tube- Tube Joints under Constant-amplitude Out-of-phase Combined Axial Loading and Torsion by Integration of Damage Differentials (IDD) S. Stefanov 1,
More information