Preface	6
	Contents	8
	1 Introduction	14
	Abstract	14
	1.1 Introduction	14
	1.2 Development Perspectives	15
	1.2.1 Increased Damage Growth Resistance of Metal Laminates	15
	1.2.2 Utilization in Context of Damage Tolerance	16
	1.2.3 Increasing Strength of Composites	17
	1.3 From Material Towards Structural Application	18
	1.4 Contribution to the FML Knowledge	18
	References	18
	2 Laminate Concepts & Mechanical Properties	20
	Abstract	20
	2.1 Introduction	20
	2.2 Aluminium with Epoxy-Based Adhesive Systems	21
	2.2.1 ARALL and GLARE, Codes and Standardisation	22
	2.2.2 Aramid Fibres (ARALL)	24
	2.2.3 Glass Fibres (GLARE, Central)	27
	2.2.4 Carbon Fibres (CARE/CARALL)	30
	2.2.5 Polymer Fibres (HP-PE, Zylon)	31
	2.2.6 M5 Fibres	33
	2.3 Other Metal Constituents	34
	2.3.1 Titanium-Based FMLs	34
	2.3.2 Stainless Steel-Based FMLs	35
	2.3.3 Magnesium-Based FMLs	35
	2.4 Thermoplastic Adhesive Systems	36
	2.5 Innovative Hybridization Concepts	36
	References	38
	3 Patents and Intellectual Property	41
	Abstract	41
	3.1 Introduction	41
	3.2 Material Concept Development	41
	3.2.1 Improving Fatigue and Crack Growth	41
	3.2.2 Improving Impact Resistance and Tolerance	44
	3.2.3 Thickness Steps	45
	3.2.4 Thick Panel Concepts for Lower Wing Covers	47
	3.2.5 Alternative Fuselage Skin Concepts	49
	3.3 Splicing Concepts	51
	3.4 Manufacturing Aspects	53
	3.4.1 Post-stretching Panels After Curing	53
	3.4.2 Pre-stretching Panels During Curing	54
	3.4.3 Lay-up and Curing Concepts	55
	3.4.4 Alternative Impregnation Processes	57
	3.5 Design of Fuselage Panels	58
	3.5.1 General Fuselage Panel Concepts	58
	3.5.2 Interlaminar Reinforcements and Inserts	59
	3.5.3 Special Design Features	61
	3.6 Design of Panel Stiffening Elements	61
	3.7 FML Components	63
	3.8 Discussion	64
	3.8.1 Flat Material Concepts	64
	3.8.2 Design Aspects	67
	3.9 Concluding Remarks	67
	References	68
	4 Stress and Strain	71
	Abstract	71
	4.1 Introduction	71
	4.2 Stress–Strain in Orthotropic Materials Under Plane Stress	71
	4.3 Classical Laminated Plate Theory	73
	4.4 Residual Stresses	73
	4.5 Failure of the Composite Constituent	76
	4.6 Plasticity of the Metal Constituent	77
	4.7 Generalized Theories of Plasticity	78
	4.8 Post-stretching	79
	4.9 Shear Stress and Strain	82
	4.10 Out-of-Plane (Bending and Torsion)	83
	4.11 Simple Methods for Design Purposes	84
	4.11.1 Metal Volume Fraction	84
	4.11.2 Determination of Shear Properties Using Uniaxial Material Data	85
	4.12 Limit of Validity of CLT and MVF	87
	References	87
	5 Blunt Notch Strength	89
	Abstract	89
	5.1 Introduction	89
	5.2 Definitions and Failure Phenomena	91
	5.2.1 Definitions	91
	5.2.2 Notch Sensitivity and Ductility	92
	5.2.3 Biaxial Loading Using Uniaxial Data	94
	5.2.4 Composite Failure Modes	95
	5.2.5 Plasticity-Induced Delamination	97
	5.2.6 Other Failure Phenomena	98
	5.2.7 Blunt Notch Strength and Ultimate Strength	99
	5.3 Theoretical Approaches	100
	5.3.1 Tsai–Hill/Norris Failure Criteria	100
	5.3.2 Point and Average Stress Criteria	101
	5.3.3 Blunt Notch Factor to Ultimate Strength in Net Section	103
	5.4 Applicability to General Loading Conditions	104
	5.4.1 Uniaxial Off-Axis Loading	104
	5.4.2 Shear Loading	106
	5.4.3 Biaxial Loading	107
	5.5 Simple Methods for Design Purposes	108
	5.5.1 Metal Volume Fraction	108
	5.5.2 Neuber’s Postulate	109
	References	111
	6 Bearing Strength	113
	Abstract	113
	6.1 Introduction	113
	6.2 Definition of Bearing Strength	114
	6.3 Failure Phenomena	115
	6.3.1 Delamination Buckling	115
	6.3.2 Bearing Failure	117
	6.4 Diameter-to-Thickness Ratio	119
	6.5 Influence of the Diameter-to-Width Ratio	120
	6.6 Influence of Edge Distance	121
	6.7 In-Axis Versus Off-Axis Loading	122
	6.8 Analysis and Prediction Methods	125
	6.8.1 Bilinear Constituent Representation with Rules of Mixtures	125
	6.8.2 Simplified MVF Method	130
	6.8.3 Finite Element Analyses	131
	6.9 Additional Studies	132
	6.9.1 Bearing/ByPass Diagrams	132
	6.9.2 Environmental Exposure	135
	References	135
	7 Fatigue Initiation	138
	Abstract	138
	7.1 Introduction	138
	7.2 Definition of Initiation	138
	7.3 Definition of Stresses	142
	7.4 Stress Concentration in a Uniaxial Stress Field	143
	7.5 Peak Stresses at Locations Other Than ? = ±90°	145
	7.6 Stress Concentration in a Biaxial Stress Field	147
	7.7 Other Load Cases	148
	7.8 Fatigue Stresses at the Notch Root	148
	7.9 Fatigue Initiation Life Estimation	150
	7.10 Adapting Reference Data for Sm and Kt	150
	7.11 Accuracy of Predictions	152
	7.12 Size Effects	153
	7.13 Constant Versus Variable Amplitude Loading	153
	7.14 Mechanically Fastened Joints	155
	7.15 Influence of Post-stretching	156
	References	157
	8 Static and Fatigue Delamination	158
	Abstract	158
	8.1 Introduction	158
	8.2 Strain Energy Release Rate	159
	8.3 Interface Geometry	161
	8.3.1 Resin-Rich Layers	161
	8.3.2 Tapes Versus Weaves	165
	8.4 Modes I, II and Mixed Mode	166
	8.4.1 Mode I	166
	8.4.2 Mode II	166
	8.4.3 Mixed Mode	169
	8.5 Constant Versus Variable Amplitude Loading	171
	8.5.1 Macroscopic Observations	171
	8.5.2 Microscopic Observations	173
	8.6 Asymptotes in Delamination Characteristics	176
	8.6.1 Static Delamination Growth	176
	8.6.2 Delamination Threshold	178
	8.7 Delamination Buckling	179
	8.8 Effect of Post-stretching	180
	References	182
	9 Fatigue Crack Propagation	185
	Abstract	185
	9.1 Introduction	185
	9.2 Crack Geometries	186
	9.3 Fatigue Crack Growth Characteristics	187
	9.4 Superposition of Far-Field Stresses and Fibre Bridging	190
	9.5 Delamination Shapes	194
	9.6 Metal Layer Crack Growth Resistance	196
	9.7 Finite Width Correction Factors	199
	9.8 Other Correction Factors	200
	9.8.1 Open Hole and Pin-Loaded Hole	203
	9.8.2 Edge Cracks Versus Central Cracks	205
	9.9 Fatigue Threshold	206
	9.10 Surface Cracks	208
	9.11 Part-Through Cracks	211
	9.12 In-Axis Versus off-Axis Loading	213
	9.13 Crack Path Angles and Path Deflections	218
	9.14 Constant Versus Variable Amplitude Loading	221
	9.15 Post-stretching	223
	9.16 Biaxial Fatigue	224
	References	227
	10 Residual Strength	231
	Abstract	231
	10.1 Introduction	231
	10.2 Through-Cut Cracks	233
	10.2.1 Fracture Mechanisms	235
	10.2.2 KR-Curve or R-Curve Concept	236
	10.2.3 Compliance Calibration for Orthotropic FML Panels	239
	10.2.4 Crack Tip Opening Angle or CTOA Concept	241
	10.2.5 Superposition Principles for Crack Opening	244
	10.2.6 In-Axis Versus Off-Axis Loading	246
	10.3 Fatigue Through Crack	247
	10.3.1 Observations	247
	10.3.2 Prediction Methodology	250
	10.4 Part-Through Cracks	251
	10.5 Surface Cracks	254
	10.6 Impact Damage Tolerance	256
	References	259
	11 Effect of Temperature	263
	Abstract	263
	11.1 Introduction	263
	11.2 Temperature-Induced Residual Stresses	263
	11.3 Thermal Properties of FMLs	264
	11.3.1 Thermal Conductivity	264
	11.3.2 Specific Heat	267
	11.4 Fatigue Initiation	267
	11.4.1 Temperature Effect on Mechanical Properties	268
	11.4.2 Temperature Effect on Fatigue Properties	269
	11.5 Fatigue Damage Growth	272
	11.5.1 Temperature and Fatigue Crack Growth Resistance of Metals	272
	11.5.2 Temperature and Fatigue Delamination Resistance	273
	11.5.3 Influence of Temperature on Damage Growth in FMLs	276
	11.6 Thermal Fatigue	277
	References	278
	12 Effect of Environment	281
	Abstract	281
	12.1 Introduction	281
	12.2 Moisture Absorption	282
	12.2.1 Planar Diffusion of Moisture	282
	12.2.2 Relevance of Exposure Type	285
	12.3 Effects of Moisture Ingress	287
	12.3.1 Static Strength	287
	12.3.2 Blunt Notch Strength	288
	12.3.3 Delamination Resistance	291
	12.3.4 Fatigue Crack Growth	293
	12.3.5 Residual Strength	294
	12.4 Effect of Frequency	297
	References	299
	13 Acoustic Fatigue	301
	Abstract	301
	13.1 Introduction	301
	13.2 Damping Characteristics	302
	13.3 Acoustic Fatigue	303
	13.4 High-Frequency Bending Fatigue Experiments	303
	13.4.1 Specimen Configuration and Test Set-up	303
	13.4.2 Test Procedure	304
	13.4.3 Performed Tests	305
	13.5 Results and Observations	306
	13.6 Concluding Remarks	308
	References	308
	Index	309