General methods of product failure evaluation give powerful tools in product improvement. Such methods, discussed in the book, include practical risk analysis, failure mode and effect analysis, preliminary hazard analysis, progressive failure analysis, fault tree analysis, mean time between failures, Wohler curves, finite element analysis, cohesive zone model, crack propagation kinetics, time-temperature collectives, quantitative characterization of fatigue damage, and fracture maps. These methods are broadly used in some industries such as automotive industry, and can be successfully applied to other industries.
Methods of failure analysis are critical to for material improvement and they are broadly discussed in this book. Fractography of plastics is relatively a new field, which has many commonalities with fractography of metals. Here various aspects of fractography of plastics and metals are compared and contrasted. Fractography application in studies of static and cycling loading of ABS is also discussed. Other methods include SEM, SAXS, FTIR, DSC, DMA, GC/MS, optical microscopy, fatigue behavior, multi-axial stress, residual stress analysis, punch resistance, creep-rupture, impact, oxidative induction time, craze testing, defect analysis, fracture toughness, activation energy of degradation.
Considering that product joints are the most common sites of failure this subject is analyzed in detail. Snap-fit joints failure of plastic housing is analyzed aiming at improvement of product reliability by redesign of method of joining. Multiply welding effect on materials durability is discussed for a broad range of temperatures of processing and performance. Effect of hot plate welding on weld properties and morphology is considered in comparison of different methods of testing. Mechanical fasteners are investigated under mechanical loads and temperature variations.
Many products have ductile properties or necking behavior which are another frequent cause of failure discussed here. Fatigue properties and fatigue failure mechanisms are discussed in detail since they cause many materials to fail.
Many references are given in this book to real products and real cases of their failure. The products discussed include office equipment, automotive compressed fuel gas system, pipes, polymer blends, blow molded parts, layered, cross-ply and continuous fiber composites, printed circuits, electronic packages, hip implants, blown and multi-layered films, construction materials, component housings, brake cups, composite pressure vessels, swamp coolers, electrical cables, plumbing fittings, medical devices, medical packaging, strapping tapes, balloons, marine coatings, thermal switches, pressure relief membranes, pharmaceutical products, window profiles, and bone cements.
Many common methods of material analysis are compared in this book. For example, effect of internal pressure and testing of tensile properties, factors affecting Gardner impact testing, standard test procedures for structural analysis, methods of exposure of materials to multidimensional state of stress, and many other.
Attention is given to material morphology and its development during processing as a practical means of material improvement. Orientation effects during welding processes are analyzed in detail. Also morphological changes of fatigue-induced damage are evaluated for crystalline polymers.
Also many different polymers are analyzed here such as polyethylene (LDPE, HDPE, UHMWPE), polypropylene, polyamide, polyoxymentylene, epoxy resins, polyvinylchloride, polystyrene, polyketone terpolymer, polyimide, polycarbonate, polyurethane, aliphatic copolymers, EPDM, ABS, vinyl ester, aromatic polyamide, polyester, polymethylmethacrylate, polyetherimide
The book also contains examples of defect cost analysis which shows that improvement of product quality by the above discussed methods is a very economical means of process engineering and technology selection. Some chapters contain discussion of 10 common pitfall in thin-wall plastic part design and outline of strategies for the evaluation of weather induced failure of polymers.
Practical Risk Analysis—As a Tool for Minimizing Plastic Product Failure
• Avoiding the GIGO Syndrome
• Defect Analysis and High Density Polyethylene Pipe Durability
• Progressive Failure Analysis of Fiber Composite Structures
• Failure Analysis Models for Polyacetal Molded Fittings in Plumbing Systems
• Estimation of Time-Temperature-Collectives at Describing Aging of Polymer Materials
• Fractography of Metals and Plastics
• Fractography of ABS
• Attachment Design Analysis of a Plastic Housing Joined with Snap-Fits
• Joint Performance of Mechanical Fasteners under Dynamic Load
• Morphological Study of Fatigue Induced Damage in Semi-Crystalline Polymers
• Ductile Failure and Delayed Necking in Polyethylene
• Fatigue Behavior of Discontinuous Glass Fiber Reinforced Polypropylene
• Translating Failure into Success—Lessons Learned from Product Failure Analysis
• Case Studies of Plastics Failure Related to Improper Formulation
• Case Studies of Inadvertent Interactions between Polymers and Devices in Field Applications
• Factors Affecting Variation in Gardner Impact Testing
• Standard Test Procedures for Relevant Material Properties for Structural Analysis
• The Influence of Multidimensional State of Stress on the Mechanical Properties of Thermoplastics
• The Influence of Morphology on the Impact Performance of an Impact Modified PP/PS Alloy
• Morphology and Mechanical Behavior of Polypropylene Hot Plate Welds
• Orientation Effects on the Weldability of Polypropylene Strapping Tape
• Activation Energies of Polymer Degradation
• Effects of Processing Conditions on the Failure Mode of an Aliphatic Polyketone Teropolymer
• Durability Study of Conductive Copper Traces within Polyimide Based Substrates
• The Role of Heat Affected Zone (HAZ) on Mechanical Properties in Thermally Welded Low Density Polyethylene Blown Film
• Plastics Failure Due to Oxidative Degradation in Processing and Service
• Comparing the Long Term Behavior of Tough Polyethylenes by Craze Testing
• Crack Propagation in Continuous Glass Fiber/Polypropylene Composites
• Freeze-Thaw Durability of Composites for Civil Infrastructure
• Temperature-Moisture-Mechanical Response of Vinyl Ester Resins and Pultruded Vinyl Ester/e-glass Laminated Composites
• Fracture Behavior of Polypropylene Modified with Metallocene Catalyzed Polyolefin
• Mechanical Performance of Polyamides with Influence of Moisture and Temperature
• Shelf Life Failure Prediction Considerations for Irradiated Polypropylene Medical Devices
• Environmental Stress Cracking of ABS IIRadiation Resistance of Multilayer Films by Instrumented Impact Testing
• Mechanical Behavior of Fabric Film Laminates
• Determining Etch Compensation Factors for Printed Circuit Boards
• Estimation of Long-Term Properties of Epoxies in Body Fluids
• Aspects of the Tensile Response of Random Continuous Glass/Epoxy Composites
• Residual Stress Development in Marine Coatings under Simulated Service Conditions
• Evaluation of a Yield Criteria and Energy Absorbing Mechanisms of Rubber Modified Epoxies in Multiaxial Stress States
• Design Aids for Preventing Brittle Failure in Polycarbonate and Polyetherimide
• Effect of Scale on Mechanical Performance of PMMA
• Defect Cost Analysis
• 10 Common Pitfalls in Thin-Wall Plastic Part Design
• Strategies for the Evaluation of Weathering-Induced Failure of Polymers
Dr. John Moalli received his doctorate in Polymers from MIT and currently serves as Director of Exponent Failure Analysis Associates' Materials Science and Mechanical Engineering group. He addresses issues related to plastics, composite materials, rubbers, adhesives, and general materials science. His specialties include product design and development, analysis of fracture surfaces, combustion behavior, experimental mechanical property evaluation, development of constitutive relations, patent analysis, and risk analysis in polymer and polymer composite systems. His current areas of research pertain to the evaluation of polymers in medical, automotive, construction, recreational, and other environments.