Fractography in Failure Analysis of Polymers

Fractography in Failure Analysis of Polymers
Michael D. Hayes
Engineering Systems Inc. (ESI), Atlanta, GA, USA
Dale B. Edwards
Engineering Systems Inc. (ESI), Aurora, IL, USA
Anand R. Shah
Engineering Systems Inc. (ESI), Aurora, IL, USA
Table of contents
Foreword
Preface
Acknowledgments

1. Introduction
   1.1 Motivations
   1.2 What Is Fractography?
   1.3 Plastic Material Structure–Property Relationship
   1.4 Components of a Failure Investigation
   References
2. Fractography as a Failure Analysis Tool
   2.1 Failure Analysis Fundamentals
   2.2 The Scientific Method
   2.3 Application of the Scientific Method
   2.4 The Role of Fractography in Failure Analysis
   References
3. Instrumentation and Techniques
   3.1 Field or Site Instrumentation and Techniques
   3.2 Microscopic Examination of Fracture Surfaces in a Laboratory
   3.3 Consideration and Selection of Instruments in Failure Analysis
   3.4 Summary
   3.5 Regulatory Agencies
   References
4. Fractography Basics
   4.1 Fracture Surface Features and Interpretation
   4.2 Brittle Versus Ductile Failures in Polymers
   4.3 Crack Path Analysis
   4.4 Fracture Features
   4.5 Application of Fractography to Failure Analysis
   References
5. Long-Term Failure Mechanisms in Plastics
   5.1 Introduction
   5.2 Creep
   5.3 SCG/Creep Rupture
   5.4 Environmental Stress Cracking
   5.5 Aging, Degradation, and Surface Embrittlement
   5.6 Summary
   References
6. Case Studies
   6.1 Introduction
   6.2 Organization of Case Studies
   6.3 Case Study 1: Composite Crossbow
   6.4 Case Study 2: Showerhead Bracket
   6.5 Case Study 3: Polycarbonate Axle Caps
   6.6 Case Study 4: Hot Water Heater Drain Valve
   6.7 Case Study 5: PEEK Coupling
   6.8 Case Study 6: Icemaker Valve Failure
   6.9 Case Study 7: Automotive Part, ABS
   6.10 Case Study 8: Seat Belt
   6.11 Case Study 9: Automotive Part, PC/ABS
   6.12 Case Study 10: CPVC Cover Plate
   6.13 Case Study 11: XLPE Storage Tank for Sulfuric Acid Storage
   6.14 Case Study 12: Oxidation Failure of HDPE Pipe in Water Service
   6.15 Case Study 13: Washing Machine Hose Failure
   6.16 Case Study 14: Polyacetal Crimp Fittings
   6.17 Case Study 15: PVC Water Main
   6.18 Case Study 16: SAN Battery Cases
   6.19 Case Study 17: Flame-Retarded Thermoformed PPE–PS
   6.20 Case Study 18: 8-in. PVC Pipe
   6.21 Case Study 19: Railcar Part, PPE+PS, 20% Glass Filled
   6.22 Case Study 20: 48-in. HDPE Pipe
   6.23 Case Study 21: HDPE Liner Pipe Used in a High-Pressure Steel Pipeline
   References
7. Epilogue
   7.1 Failure Prevention
   Index
   Index
   Note: Page numbers followed by “f” and “t” refer to figures and tables, respectively.
   A
   Acetal, 12
   13
   Acetal crimp fitting, degradation of,
   106, 108f
   Acronyms, for commonly used plastic
   materials, 27t
   Acrylonitrile butadiene styrene
   (ABS), 104
   105, 141
   142,
   143f, 144, 144f
   fractured ABS boat steering wheel,
   106, 106f, 107f
   Aging, 103
   108
   American Association for the
   Advancement of Science, 17
   Amorphous thermoplastic, 3
   Archive, 14
   Argument from ignorance, 16
   ASTM D1600, 27
   28
   ASTM E1188, 36
   Automotive part, ABS (case study)
   anti-rattle trigger post, fracture
   surface of, 143f, 144f
   anti-rattle trigger post, overall
   appearance of, 142f
   background, 141
   conclusions, 144
   145
   failure analysis, 141
   144
   fracture, location of, 143f
   material flow and orange-peel-like
   surface finish of anti-rattle
   trigger post, 142f
   techniques, 141
   Automotive part, PC/ABS
   (case study), 148
   152
   background, 148
   conclusions, 151
   152
   failure analysis, 149
   151
   fracture origin location, 150f
   fracture progression in brittle
   manner, 151f
   fracture surface under stereozoom
   optical microscope, 150f
   new uncracked and cracked PC/
   ABS instrument panel, overall
   appearance of, 149f
   techniques, 148
   149
   B
   Background information, gathering,
   23, 26
   27
   Beach marks. See Rib markings
   Bifurcations of crack, 52
   Branching of crack. See Crack
   branching
   Brittle, 94
   Brittle fractures, 55
   57
   Brittle versus ductile failures, in
   polymers, 53
   60
   cautions, 59
   60
   plane stress and plane strain,
   57
   59
   C
   Carbonyl index (CI), 105
   106
   Case studies, 111
   automotive part
   ABS, 141
   145
   PC/ABS, 148
   152
   composite crossbow, 114
   120
   CPVC cover plate, 152
   156
   8-in. PVC pipe, 190
   195
   227Case studies (Continued)
   flame-retarded thermoformed
   PPE-PS, 185
   190
   48-in. HDPE pipe, 203
   211
   HDPE liner pipe used in a highpressure steel pipeline,
   211
   221
   hot water heater drain valve,
   128
   130
   icemaker valve failure, 134
   141
   oxidation failure of HDPE pipe in
   water service, 165
   168
   PEEK coupling, 130
   134
   polyacetal crimp fittings, 173
   177
   polycarbonate axle caps, 123
   127
   PVC water main, 177
   180
   railcar part, PPE 1 PS, 20% glass
   filled, 195
   203
   SAN battery cases, 180
   185
   seat belt, 145
   148
   showerhead bracket, 120
   123
   washing machine hose failure,
   168
   173
   XLPE storage tank for sulfuric acid
   storage, 156
   165
   Causes versus mechanisms, 6
   7
   Chemical evident on fracture
   surface, 53
   Compound microscopes, 39
   Compounding additives, 44
   Conic markings, 88, 88f
   CPVC cover plate,
   case study, 152
   156
   background, 152
   conclusions, 155
   156
   cracks at second machined
   hole in, 153f
   failure analysis, 152
   155
   fluid emanating from crack in,
   154f, 155f
   fracture origin area near
   machined hole, 154f
   fracture surface from fractured
   CPVC cover plate, 153f
   fractures at machined hole, 152f
   sharp ledges on very smooth
   surface, 154f
   techniques, 152
   CPVC elbow fitting, 29
   CPVC ESC failure, 89, 90f
   CPVC pipe, 83
   84, 85f
   crack in, 102f
   depict fracture surfaces
   of, 83
   84, 85f
   evidence of microductility on
   fracture surface of, 102f
   mechanically driven
   crack in, 103f
   Crack arrest marks, 70
   71
   Crack branching, 52, 61, 62f
   Crack growth, 7, 59
   60, 61f, 77
   Crack opening displacement, 34
   Crack path analysis, 61
   62
   Crack propagation, 74, 94, 165
   166,
   190
   191
   Crazing in polymers, 57
   Creep, 93
   95
   brittle, 94
   deformation, 94
   glass transition temperature, 95
   response, 94
   rupture, 94
   failure, 48
   49, 86
   87
   Critical stress, 98
   100, 102
   103
   Crossbow, case study, 114
   120
   additional secondary cracks along
   fractured area, 116f
   background, 114
   115
   conclusions, 119
   120
   fractured crossbow, 115f
   fractured end of, 116f
   large voids and stress whitening,
   117f
   stress whitening and rubbed
   surface of, 119f
   surface damage near fracture
   origin area, 116f
   techniques/analysis, 115
   119
   228 INDEXvisibility of internal voids on
   fracture surface, 118f
   visibility of large voids in the
   interior of stock, 118f
   voids near fracture origin at the
   underside of crossbow body,
   118f
   wear marks on stock near fracture
   origin, 117f
   Cross-linked PE (PEX) pipe
   cracks branching in, 62f
   fracture origin at a void in, 65f
   undercut ledges
   on fracture surface near origin
   in, 90f
   in PEX tank fracture near
   origin, 90f
   D
   Damage development, 7
   Daubert v. Merrell Dow
   Pharmaceuticals, Inc., 19
   Deductive reasoning, 14
   16
   Defects versus imperfections, 9
   12
   Degradation, 64, 71
   73, 103
   108
   Design defects, 8
   9
   Design deficiencies, 12
   13
   Differential scanning calorimeter
   (DSC), 44
   Documentation, 26
   photo, 31f, 35f
   Ductile creep failures, 95
   Ductile failures, in polymers, 53
   60
   Ductile fracture origin, 68f
   Ductility, on fracture surface, 49
   Dye penetrants, 41, 42f
   E
   Electromagnetic lenses, 43
   Embrittlement, 103
   108
   Energy-dispersive X-ray spectroscopy
   (EDS), 171, 183, 192, 208
   Environmental SEM (E-SEM),
   42
   43
   Environmental stress crack resistance
   (ESCR) testing, 208, 212
   Environmental stress cracking (ESC),
   96
   103, 127, 140, 152
   153,
   155
   156, 181
   183,
   185
   190, 196
   198
   agent, 96
   97
   characteristics of, 96
   differentiating SCG/creep from,
   100
   103
   failures, 49, 67f
   Environmental variables affecting
   product performance, 225t
   Evidence, definition of, 14
   F
   Fabrication errors, 8
   9
   Failure analysis fundamentals, 6
   13
   causes versus mechanisms, 6
   7
   defects versus imperfections, 9
   12
   design deficiencies, 12
   13
   fractography’s role in, 20
   21
   material selection, 12
   13
   primary versus secondary causes, 8
   root causes, types of, 8
   9
   Failure investigation, 23
   basic elements, 17
   components of, 3
   4
   “Failure of will,” fallacy of, 15
   Failure prevention, 223
   226
   Fallacies/user error, 15
   16
   Fallacious logic, 15
   16
   Fast fracture area on fracture surface,
   52
   53
   Fatigue striations, 78
   87
   fatigue crack growth versus slow
   crack growth, 83
   87
   on fracture surface of PS
   toothbrush failure, 78
   81, 80f
   on fracture surface of SAN field
   fracture, 78
   81, 80f
   on HDPE pipe fracture surface,
   78
   81, 81f
   Field investigation, 24
   38
   INDEX 229Field investigation (Continued)
   field microscopy, 37
   information gathering, 25
   26
   photogrammetry and digitization,
   37
   38
   product specific information, visual
   inspection for, 26
   33
   visual and photographic
   techniques, 33
   37
   Finite element analysis (FEA), 140f,
   163, 171, 172f, 174
   175, 196,
   200, 202
   Flame-retarded thermoformed PPEPS, case study, 185
   190
   background, 185
   conclusions, 189
   190
   cracking at thermoformed bend in
   the bus seat material, 187f
   cracking of plastic seat material
   adjacent to attachment to
   frame, 186f
   cracks around attachment hole in
   seat material, 186f
   failure analysis, 186
   189
   SEM images of cracks, 187f
   smooth fracture origin at outer
   surface of the seat panel, 188f
   strain measurements, 188
   189,
   189f
   techniques, 185
   186
   Flaw, 10
   Foreign materials on fracture
   surface, 53
   Forking, 61
   Fourier transform infrared (FTIR)
   spectroscopy, 152, 155f
   Fractography, definition of, 2
   Fracture features, 62
   90
   conic or parabolic
   markings, 88, 88f
   fatigue striations, 78
   87
   fatigue crack growth versus slow
   crack growth, 83
   87
   fracture origin(s), 63
   65
   hackles, 74
   75
   mirror zone, 66
   70
   mist region, 70
   ratchet marks or
   ledges, 89
   90, 89f
   rib markings/beach marks, 70
   73
   river patterns or river markings,
   75
   77
   Wallner lines, 77
   78
   Fracture modes, 51
   52, 52f
   Fracture origin, 64
   66
   at geometric discontinuity in
   PMMA, 66f
   at an inclusion in PVC, 65f
   at a void in PEX tube, 65f
   Fracture surface, 48
   53
   acrylic, 74, 76f
   bifurcations of crack, 52
   crack branching, 52
   ductility, 49
   failure characteristics, 48
   49
   fast fracture area on, 52
   53
   foreign materials or
   chemicals on, 53
   fracture direction for mating
   parts, 51
   52
   location and nature of fracture
   origin, 49
   microscopic examination of,
   38
   43
   optical microscopy, 39
   41
   scanning electron microscopy
   (SEM), 42
   43
   river patterns/hackles on, 77, 77f
   roughness, 50
   slow crack growth (SCG) region
   on, 52
   53
   smoothness, 50
   straight/curved crack, 52
   stress whitening on, 50
   striations/lines on, 51
   T-junctions, 52
   undercut ledges on, 82, 90f
   various features of, 64f
   230 INDEXFracture type, identification of, 21
   Frye test, 19
   G
   Gel permeation chromatography
   (GPC), 147
   148, 147t
   Glass transition temperature, 95
   H
   Hackles, 74
   75, 75f
   HDPE liner pipe used in a highpressure steel pipeline, case
   study, 211
   221
   background, 211
   212
   conclusions, 220
   221
   failed liner pipes
   long fracture surfaces in, 213f
   typical outer surface gouges and
   scratches on, 212f
   failure analysis, 212
   220
   mechanical testing, 212
   multiple fracture origins, 150
   151,
   213
   215, 214f
   HDPE pipe, 49
   48-in. HDPE pipe (case study),
   203
   211
   background, 203
   204
   conclusions, 211
   cracks on inner surface of pipe
   sample, 205f
   cracks in the pipe, exposing,
   206f
   failure analysis, 209
   211
   fracture surfaces of different
   cracks, 206f, 207f
   material testing, 208
   209
   pipe section with approximate
   location of through-wall
   cracks, 204f
   section of HDPE pipe received
   for analysis, 203f
   techniques, 204
   209
   wall thickness measurements,
   204f, 205f
   crazing ahead of fatigue crack in,
   70, 71f, 72f
   degradation of, 107
   108
   failure in, 74f
   mud cracking of inner surface
   of, 108f
   point load failure in, 73f
   rib markings on, 73f
   in water service, oxidation failure
   of (case study), 165
   168
   background, 165
   conclusions, 168
   crack in pipe after sectioning the
   pipe longitudinally, 166f
   embrittled inner surface, SCG,
   and mud cracking on inner
   surface of the pipe, 167f
   failure analysis, 166
   168
   five mil depth of degraded
   material at inner surface, 167f
   HDPE pipe sample with
   crack, 166f
   techniques, 165
   166
   HDPE tensile test specimen, 54
   55
   before and after testing, 55f
   notched and cooled in liquid
   nitrogen, 56f
   tested with razor notch, 56f
   High-density polyethylene. See HDPE
   Hooke’s law, 57
   58
   Hot water heater drain valve, case
   study, 128
   130, 128f
   background, 128
   conclusions, 130
   techniques and
   analysis, 128
   130, 129f
   Human roots, causes of failure, 9
   I
   Icemaker valve failure, case study,
   134
   141
   background, 134
   135
   conclusions, 141
   failure analysis, 138
   141, 139f
   INDEX 231Icemaker valve failure, case study
   (Continued)
   Faro laser scan deviation plots
   for subject plate, 138f
   for typical exemplar plate, 138f
   inspection, 135
   137
   crack on outlet stem portion of
   valve body, 136f
   lab examination, 135
   137
   laser scan of guide plates, 137
   separated valve body showing
   fracture surfaces, 136f
   subject icemaker, 134f, 135f
   Imperfections, 9
   12
   Inadmissible evidence, 15
   Inductive reasoning, 14
   16
   Information gathering, 25
   26
   environmental factors, 26
   Injection molding, 29, 30f
   Instrumentation/techniques
   consideration and selection of,
   43
   45, 45t
   field/site investigation, 24
   38
   field microscopy, 37
   information gathering, 25
   26
   photogrammetry and digitization,
   37
   38
   product specific information,
   visual inspection for, 26
   33
   visual and photographic
   techniques, 33
   37
   microscopic examination of
   fracture surfaces, 38
   43
   environmental SEM
   (E-SEM), 42
   43
   optical microscopy, 39
   41
   scanning electron microscopy
   (SEM), 42
   43
   regulatory agencies, 46
   47
   Irrelevant evidence, 15
   L
   Laser scanning, 25, 38
   Latent roots, 9
   Linear elastic fracture mechanics
   (LEFM), 179, 194
   Linear-low-density polyethylene
   (PELLD), 28
   Liquid crystal polymer (LCP), 82
   fatigue failure in, 84f
   fracture origin at the edge of, 85f
   Litigation standard, 18
   20
   Frye test, 19
   physical evidence, 18
   U.S. Federal Rules of Evidence
   702 (FRE), 19
   20
   Logic, definition of, 14
   Logic fallacies, 15
   16
   Long-term failure mechanisms, in
   plastics
   aging, 103
   108
   creep, 93
   95
   degradation, 103
   108
   environmental stress cracking
   (ESC), 96
   103
   differentiating SCG/creep from,
   100
   103
   SCG/creep structure, 95
   96
   surface embrittlement, 103
   108
   Low-density polyethylene (LDPE)
   resin, 145, 146f, 147
   148,
   147f
   M
   Manufacturer, identifying, 28
   Manufacturing date, documenting, 32
   Manufacturing defects, 8
   9
   Material defects, 8
   9
   Material properties, 44
   45, 45t
   Material selection, 12
   13, 224
   Microcracking, 35, 107f
   Microscopic examination of fracture
   surfaces, 38
   43
   optical microscopy, 39
   41
   scanning electron microscopy
   (SEM), 42
   43
   environmental SEM (E-SEM),
   42
   43
   232 INDEXMicrovoids in plastics, 59
   60
   Mirror zone, 66
   70, 69f
   Mist region, 70, 71f
   Mode of failure, 6
   7
   Mud cracking, 106, 108f
   N
   National Fire Protection Association
   (NFPA), 16
   17
   Noryl resin, 185
   190, 195
   196,
   202
   203
   GFN2 701 material, 200
   202
   stress rupture curve for, 202f
   mechanical properties of, 188t
   Nylon axial fatigue test, 82, 83f
   O
   Optical microscopy, 23, 39
   41
   categories of, 39
   limitations of, 40
   41
   Organic synthetic polymers, 2
   3
   Oxidation induction time (OIT),
   159
   160, 165
   166, 168
   P
   Parabolic markings, 88, 88f
   Part failure, 1
   2
   PE 3408 tensile specimen
   brittle fracture of, 54
   55, 56f
   ductile failure of, 54
   55, 55f, 56f
   PEL model, 14
   PELA model, 14
   Photogrammetry and
   digitization, 25, 37
   38
   laser scanning, 38
   PhotoModeler Scanner software,
   37
   38
   Physical evidence, 16, 18
   Physical roots, 9
   Plane strain, 57
   59, 95
   96
   Plane stress, 57
   59
   Polyacetal crimp fittings, case study,
   173
   177
   background, 173
   conclusions, 176
   177
   crimp fitting assembly, schematic
   of, 175f
   failure analysis, 173
   176
   field failure, 174f
   techniques, 173
   Polycarbonate (PC) axle caps, case
   study, 123
   127
   appearance of fracture surface
   showing crack initiation, 125f
   background, 123
   conclusions, 127
   failed axle cap with complete
   circumferential fracture, 124f
   failure analysis, 125
   127, 127f
   molding flaws, 125f, 126f
   observations, 123
   125
   partial crack under flange near
   gate, 124f
   two truck wheel axle caps, 124f
   Polycarbonate part, depict fracture
   surfaces of, 83
   84, 86f
   Polyetherether ketone (PEEK)
   coupling, case study,
   130
   134, 131f
   background, 130
   conclusions, 134
   failure analysis, 133
   134
   multiple fracture origins and
   fatigue striations, 133f
   multiple initiation sites and fatigue
   striations, 132f
   observations, 130
   132
   semi-elliptical fatigue fracture
   origins, 131f
   small cutout fragment, 131f
   fracture surface on, 131f
   surface and microvoids/
   microcracks, 133f
   thin section of cutout fragment,
   mating fracture in, 132f
   Polyethylene (PE), 97
   98
   high-magnification fracture
   surface in, 60f
   INDEX 233Polyethylene (PE) (Continued)
   low-magnification view of
   SCG in, 60f
   Polymer classification, 2
   3
   Polymer material variables, 224t
   Polymeric materials, basic fracture
   features in, 63t
   Polymethyl methacrylate (PMMA)
   fracture origin at geometric
   discontinuity in, 66f
   mirror zone at the origin area of
   brittle fracture in, 68f
   multiple crazes in, 54
   Polyphenylene ether
   polystyrene
   (PPE-PS) material, 50
   ESC failure in, 51f
   Polystyrene (PS), 48
   49, 81
   82, 82f
   Polyvinyl chloride
   (PVC), 155
   156, 177
   180,
   177f, 190
   195
   8-in. PVC pipe, case study,
   190
   195
   background, 190
   conclusions, 194
   195
   crack initiation area, 193f
   critical pressure versus crack
   length, 195f
   failed PVC pipe, 191f
   failure analysis, 193
   194
   fractographic observations prior
   to destructive examination,
   191f
   fracture initiation region, 192f
   fracture surface,
   stereomicroscopy of, 192f
   techniques, 190
   192
   fracture origin at an
   inclusion in, 65f
   fracture surface, parabolic
   markings visible on, 88, 88f
   PVC water main, case study,
   177
   180
   background, 177
   conclusions, 180
   fracture origin area in the bell
   end of PVC pipe, 177f
   fracture origin showing SCG area
   and fast fracture area, 178f
   techniques and analysis,
   177
   180
   Presuppositions, 14
   15
   Processing variables, 224
   225, 225t
   Product performance, environmental
   variables affecting, 225t
   Product specific information, visual
   inspection for, 26
   33
   Punctuation marks, 27
   28
   R
   Railcar part, PPE 1 PS, 20% glass
   filled (case study), 195
   203
   background, 195
   196
   conclusions, 202
   203
   cracking, 197f, 198f
   evidence of fibers running
   longitudinal to the direction of
   fracture, 200f
   failure analysis, 196
   202
   finite element analysis, 200
   201
   stress relaxation testing, 202
   stress rupture testing, 201
   202
   thermogravimetric analysis
   (TGA), 198
   200
   fracture surface, examining, 199f
   techniques, 196
   vent assembly, 197f
   Ratchet marks/ledges, 89
   90, 89f
   Red herring, 10
   12, 15
   Retardation, 184
   Rib markings, 70
   73, 72f, 73f, 74f
   River markings, 75
   77
   River patterns, 75
   77
   Root cause, 2
   3
   definition of, 8
   failure analysis, 8
   types of, 8
   9
   Rotational molding, 32
   33
   Rubbers, 2
   3
   234 INDEXS
   Safety concerns, checking, 25
   Scanned electron beam, 43
   Scanning electron microscopy (SEM),
   23, 42
   43, 113
   environmental SEM (E-SEM),
   42
   43
   Scientific method, 13
   16
   applications of, 16
   20
   litigation standard, 18
   20
   multidisciplinary approach,
   17
   18
   deductive versus inductive
   reasoning, 14
   16
   Seat Belt, case study, 145
   148
   background, 145
   conclusions, 148
   cracked LDPE seat belt
   scabbard, 146f
   failure analysis, 145
   147
   LDPE seat belt scabbard, fracture
   surface of, 147f
   loading on seat belt scabbard,
   single point source of, 146f
   techniques, 145
   Semicrystalline materials, 66
   67
   Semicrystalline polymers, 3,
   224
   225
   Service life anomalies, 8
   9
   Shear yielding, 56
   57
   Showerhead bracket, case study,
   120
   123
   background, 120
   conclusions, 123
   crack initiation at injection
   gate, 122f
   cracking at gate location, 121f
   failure analysis, 121
   123
   fractured bracket, 121f
   hand-held shower product, overall
   view of, 120f
   higher magnification of crack at
   gate, 122f
   observations, 120
   121
   Simple microscopes, 39
   Site investigation. See Field
   investigation
   Slow crack growth (SCG), 48,
   52
   53, 59
   60
   continuous SCG in HDPE samples,
   84
   85, 86f
   discontinuous SCG in HDPE
   samples, 84
   85, 87f
   versus fatigue crack growth,
   83
   87
   low-magnification view of, in
   polyethylene, 60f
   SCG/creep rupture, 95
   96
   versus environmental stress
   cracking, 100
   103
   Solid-state structure, development
   of, 224
   225
   Stereomicroscopes, 39
   Strain optical coefficient, 184
   Straw-man argument, 16
   Stress crack agents, 100t, 101
   102
   Stress cracking failures in
   polyethylene, 97
   98
   Stress intensity factor, 69
   70,
   179
   180, 194
   Stress state, 58
   ahead of cracked or notched
   material, 58f
   in notched material, 59f
   Stress whitening on fracture surface,
   50
   Striations on fracture surface, 51
   Structure
   property
   relationship, 2
   3, 44
   Styrene acrylonitrile (SAN) battery
   cases, case study, 180
   185
   background, 180
   conclusions, 185
   example of cracks, 181f
   failure analysis, 183
   184
   material found on fracture
   surface, 182f
   observations, 180
   182
   INDEX 235Styrene acrylonitrile (SAN) battery
   cases, case study (Continued)
   photoelastic birefringence patterns
   around gates, 184f
   typical fracture surface, 182f
   Styrene acrylonitrile (SAN) field
   fracture, 78
   81, 80f
   Surface embrittlement of polymers, 103
   T
   Tensile test, 54, 54f
   HDPE, 55f, 56f
   Thermoplastic, 2
   3
   Thermosets, 2
   3
   T-junctions, 52, 61
   62
   Twist hackle, 74
   75, 76f, 77
   U
   Undercut ledges on fracture surface,
   82, 90f
   Uniaxial and biaxial stress states,
   56
   57
   U.S. Federal Rules of Evidence 702
   (FRE), 19
   20
   “Unobtainable perfection,” 15
   User errors, 8
   9, 15
   UV degradation, 104
   V
   Variabilities in materials, 10
   Viscoelasticity, 93
   94
   Visual and photographic techniques,
   33
   37, 36t
   ASTM E1188, 36
   digital camera and accessories,
   33
   34, 34t
   hand-held instruments, 33
   microcracks identification, 35
   Visual inspection for product specific
   information, 26
   33
   manufacturing date, documenting, 32
   rotational molding, 32
   33
   V-shaped dual gooseneck flexible
   light adapter, 39
   W
   Wallner lines, 77
   78, 78f, 79f
   Washing machine hose failure, case
   study, 168
   173
   background, 168
   conclusions, 173
   crack pattern on inner surface, 169f
   exemplar part, cross section of,
   172f
   failed washing machine hose, 169f
   failure analysis, 171
   172
   FEA of tube in bending that is
   constrained on right end, 172f
   fracture surface, 169f
   fracture surface, 170f
   observations, 168
   171
   tool marks, 170f
   Wehnelt cylinder, 42
   X
   XLPE storage tank for sulfuric
   acid storage, case study,
   156
   165
   background, 156
   158
   bottom surface of the tank, 157f
   changes in elevation, visualizing,
   160, 161f
   conclusions, 163
   165
   crack in bottom panel, 157f
   ductility on fracture surface, 159f
   failure analysis, 159
   163
   hackles in final fracture region near
   outer surface, 161f
   microcracking, 159f
   removed section containing crack
   (s), 157f
   step at tailing edge of a void in
   UHMWPE, 162f
   step in PC, 161f
   step in PE, 162f
   steps at an inclusion in PE
   pipe, 162f
   subject tank, 156f
   techniques, 158

كلمة سر فك الضغط : books-world.net
The Unzip Password : books-world.net