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A Unified Statistical Methodology for Modeling Fatigue Damage

:	Enrique Castillo, Alfonso Fernandez-Canteli
:	A Unified Statistical Methodology for Modeling Fatigue Damage
:	Springer-Verlag
:	9781402091827
:	1
:	CHF 85.50
:

:	Maschinenbau, Fertigungstechnik
:	English

:	232
:	Wasserzeichen/DRM
:	PC/MAC/eReader/Tablet
:	PDF

This book is an attempt to provide a uni?ed methodology to derive models for fatigue life. This includes S-N, ?-N and crack propagation models. This is not a conventional book aimed at describing the fatigue fundamentals, but rather a book in which the basic models of the three main fatigue approaches, the stress-based, the strain-based and the fracture mechanics approaches, are contemplated from a novel and integrated point of view. On the other hand, as an alternative to the preferential attention paid to deterministic models based on the physical, phenomenological and empirical description of fatigue, their probabilistic nature is emphasized in this book, in which stochastic fatigue and crack growth models are presented. This book is the result of a long period of close collaborationbetween its two authors who, although of di?erent backgrounds, mathematical and mechanical, both have a strong sense of engineering with respect to the fatigue problem. When the authors of this book ?rst approached the fatigue ?eld in 1982 (twenty six years ago), they found the following scenario: 1. Linear, bilinear or trilinear models were frequently proposed by relevant laboratoriesandacademiccenter toreproducetheW¨ ohler?eld. Thiswas the case of well known institutions, which justi?ed these models based on clientrequirementsorpreferenc s. Thisledtotheinclusionofsuchmo els and methods as, for example, the up-and-down, in standards and o?cial practical directives (ASTM, Euronorm, etc.), which have proved to be unfortunate.

	I Introduction and Motivation of the Fatigue Problem	14
	An Overview of Fatigue Problems	15
	Introduction	16
	Models with dimensionless variables	16
	S-N or Wöhler curves	18
	Compatibility condition of N\| and \|N	21
	Statistical considerations	23
	-N curves	24
	Stress level effect	25
	Compatibility condition of S-N curves for constant m* and S-N curves for constant M*	26
	Crack growth curves	28
	Crack growth curves for a constant stress pair T*	30
	Crack growth curves for a varying stress pair T*	32
	Compatibility of crack growth and S-N models	34
	Crack growth rate curves	34
	Size effect	37
	Normalization	38
	Percentile based normalizations	38
	Stress range and lifetime based normalizations	41
	Extended percentile normalization	42
	Damage measures and damage accumulation	43
	II Models Used in the Stress Based Approach	45
	S-N or Wöhler Field Models	46
	Introduction	47
	Dimensional analysis	49
	Extreme models in fatigue	52
	The Weibull model	52
	The minimal Gumbel model	53
	Model for constant stress range and level	54
	Derivation of the model	54
	Parameter estimation	56
	Alternative methods for dealing with run-outs	59
	Model for varying range and given stress level	60
	Derivation of the model	60
	Some weaknesses of the proposed model	64
	Parameter estimation	66
	Use of the model in practice	67
	Example of application	68
	Model for varying stress range and level	70
	Dimensional Weibull and Gumbel models	75
	Properties of the model	76
	Parameter estimation	80
	Use of the model in practice	82
	Example of applications	83
	Concluding remarks	95
	Appendix A: Derivation of the general model	96
	Appendix B: S-N curves for the general model	100
	Length Effect	102
	Introduction	102
	Modeling the S-N field for different lengths	106
	A previous example	106
	General model for different lengths	108
	Parameter estimation	109
	Examples of Application	111
	Prestressing wires	111
	Prestressing strands	116
	III Models Used in the Strain Based Approach	121
	Log-Weibull -N Model	122
	Introduction	122
	Model for constant strain range and level	125
	Practical example	128
	Model for varying strain range and level	128
	Converting strain- into stress-life curves	130
	Practical example	132
	Concluding remarks	133
	IV Models Used in the Fracture Mechanics Approach	135
	Crack Growth Models	136
	Introduction and motivation	136
	Building crack growth models	138
	Crack growth curves approach I	142
	Crack growth curves for constant * and *	142
	Crack growth curves for varying * and *	145
	Compatibility of crack growth and S-N models	148
	Crack growth curves approach II	151
	Crack growth curves for constant * and *	151
	Crack growth curves for varying * and *	153
	Statistical distributions of a\|N and N\|a	156
	Learning and estimating the model	159
	Compatibility of approaches I and II	160
	Example of application	161
	Summary and future work	163
	V Damage and Damage Accumulation Models	165
	Damage Measures	166
	Introduction	166
	Normalization	170
	Damage measures	172
	Some requirements for a damage measure	172
	Some damage measures	173
	Concluding remarks	179
	Damage Accumulation	180
	Damage accumulation	180
	Accumulated damage after a constant stress range load step	185
	Accumulated damage after block loading	186
	Fatigue under a general loading history	187
	Random loading	191
	Crack growth damage for any load history	191
	VI Appendices	195
	Models Used in Fatigue	196
	Introduction	196
	S-N curve models	199
	The Wöhler model	199
	The Basquin model	201
	The Strohmeyer model	202
	The Palmgren model	202
	The Stüssi model	203
	The Weibull model	203
	The Spindel and Haibach model	203
	The Kohout and Vechet model	204
	Stress field models	205
	The Pascual and Meeker model	205
	The Bastenaire model	205
	The Castillo et al. (1985) model	207
	Fatigue limit models	208
	The up-and-down method	208
	Notation Used in This Book	216
	Bibliography	216
	Index	222