Description
Book SynopsisThe book presents topical theoretical and experimental studies for developing advanced methods of detecting materials fracture and assessing their structural state using acoustic emission. It introduces new mathematical models characterizing the displacement fields arising from crack-like defects and establishes a new criterion for classifying different types of materials fracture based on specific parameters obtained from wavelet transforms of acoustic emission signals. The book applies this approach to experimental studies in three types of materials—fiber-reinforced composites, dental materials, and hydrogen-embrittled steels.
Table of Contents1 Macrofracture of Structural Materials and Methods of Determining its Type................................................................................................... 1
1.1 Types of Structural Materials Fracture................................................................ 1
1.2 Application of the Acoustic Emission Method to Detect
the Fracture of Structural Materials...................................................................... 8
1.3 Detection of Defects by Signals
of Magnetoelastic Acoustic Emission ................................................................ 19
1.4 Methods of Spectral Analysis of AE Signals................................................... 21
1.5 Application of Wavelet Transform for
Analysis of AE signals........................................................................................... 31
References............................................................................................................................... 43
2 Mathematical Models for Displacement Fields Caused by
the Crack in an Elastic Half-Space............................................................................ 61
2.1 Basic Relations of Three-Dimensional Dynamic Problems
of the Theory of Elasticity for Bodies with Cracks........................................... 62
2.2 Modeling of Wave Displacements Field on the Half-Space
Surface due to Displacement of the Internal Crack Faces............................... 68
References............................................................................................................................ 102
3 Energy Criterion for Identification of the Types of
Material Macrofracture............................................................................................. 105
3.1 Methods for Identifying the Types of Macrofracture................................... 105
3.2 Construction of the Energy Criterion.............................................................. 108
3.3 Continuous Wavelet Transform of the AE Signals Emitted
under Fracture of Aluminum and its Alloy...................................................... 123
3.4 Specific Features of the Acoustic Emission Signals During Fracture of Aluminum Alloy Welded Joints under
Quasi-Static Loading............................................................................................ 130
3.5 AE-identification of the Types of Fracture during
Low-Temperature Creep Crack Growth........................................................... 135
3.6 Application of the Wavelet Transform to Study the
Features of Non-Metallic Materials Fracture................................................... 140
References............................................................................................................................ 144
vii
4 Evaluation of the Types and Mechanisms of Fracture
of Composite Materials According to Energy Criteria...................................... 151
4.1 Specific Features of Macrofracture of the Glass
Fiber Reinforced Composites............................................................................ 152
4.2 AE-diagnostics of Fracture of the Aramid
Fiber Reinforced Composites............................................................................ 159
References............................................................................................................................ 179
5 Ranking of Dental Materials and Orthopedic Constructions
by their Tendency to Fracture.................................................................................. 185
5.1 State-of-the Art of Researches on Mechanical Properties
of Dental Materials............................................................................................. 186
5.2 Determination of the Characteristics of Materials for Temporary
Fixed Constructions of Dentures...................................................................... 187
5.3 Evaluation of the Types of Dental Polymer Fracture by
the Energy Criterion........................................................................................... 199
5.4 Peculiarities of Some Tooth-Endocrown
Systems Fracture under Quasi-Static Loading............................................... 205
References............................................................................................................................ 220
6 Rating of Hydrogen Damaging of Steels by Wavelet
Transform of Magnetoelastic Acoustic Emission Signals................................. 227
6.1 Some Aspects of Operation the Technical Systems
in Hydrogenous Medium................................................................................... 228
6.2 Method for Estimating the Hydrogen Damage of Structural
Materials by Wavelet Transform of MAE Signals........................................ 232
6.3 Approbation of the Research Technigue on Specimens of
Long-Term Operated Pipe Steels..................................................................... 244
References............................................................................................................................ 255
