IM417 Failure Analysis Lecture 1 Introduction PDF

IM417 – Failure Analysis Lecture 1: Introduction Dr. Mohamed Khamis Industrial and Management Engineering 2020/2021 Course File Summary: IM417 Failure Analysis Course Information Course Title: Failure Analysis Code...

IM417 – Failure Analysis Lecture 1: Introduction Dr. Mohamed Khamis Industrial and Management Engineering 2020/2021 Course File Summary: IM417 Failure Analysis Course Information Course Title: Failure Analysis Code: IM417 Hours: Lecture: 2 Tutorial: 2 Credit: 3 Prerequisites: IM315 Lecturer: Dr. Mohamed Khamis Assistant: Eng. Nouran Delivery: Lectures Offline Tutorials and Lab, Room 107: Offline Grading 7th week: 30% (20% exam + 10% section assignments, quizzes & attendance). 12th week: 20% (10% exam + 10% section assignments, quizzes & attendance). Continuous assessment: 10% (9th week Project & 13th week Case study). Final Exam: 40% Course Description Techniques for failure analysis; Modes of mechanical failure, Residual stresses, Brittle and ductile fracture, Fatigue fracture, Wear, Corrosion, Elevated-temperature failures, Non-destructive testing, Case histories. Text Book WULPI, D.J. – Understanding How Components Fail – American Society for Metals, Metals Park, Ohio, 1985. Reference Books HUTCHING, F.R and UNTERWEISER, P.M. – Failure Analysis: The British Engine Technical Reports – American society for Metals, Metals Park, Ohio, 1981. BARER, R.D. and PETERS, B.F. – Why Metals Fail – Gordon & Breach, Science Pub., 1970. ASM – Metals Hand Book, Volumes 9, 10, American Society for Metals, Metals Park, Ohio, 1983. Course Outline Week 1: Introduction Week 2: Mechanical Behavior of Materials I Week 3: Mechanical Behavior of Materials II Week 4: Techniques of Failure Analysis Week 5: Residual stresses Week 6: Material Defects I Week 7: Exam Week 8: Material Defects II Course Outline Week 9: Elevated Temp Failures (CREEP) Week 10: Ductile and Brittle Fracture Week 11: Fatigue Failures Week 12: 12th week Exam Week 13: Wear Week 14: Corrosion Failures Week 15: NDT Week No. 16: Final Exam Introduction How and When Metals Fail Failure Analysis Failure is a Huge Issue, many failure modes and mechanisms, failures may overlap, lots of disputes. There always exceptions We will focus on – Some common failures – Failure analysis process Highlight some interesting failures primarily for steel, but present in most materials What is Failure? Part and/or system no longer complies with design intent for part or system. Not always structural – Leaking hydraulic seals – Inappropriate stiffness in component – Rate of corrosive decay/breakdown – Part/system lifetime – Operating/maintenance costs Any design parameter Objective of Failure Analysis Investigation of material facts associated with a part or system failure. To Determine ◦ Timeline, chain of events ◦ Root-cause of incident / contributing factors ◦ Post incident fitness for purpose ◦ Repair options ◦ Mitigating future failures Contributing Factor Areas Original Design Material Properties Manufacturing and processing Service Factors –Loading –Environment Repair Procedures –Weld Repair Failure Analysis Process 1. Problem definition 2. Collection of background data 3. Formulate hypothesis 4. Develop test methodologies 5. Implement tests / collect data 6. Review results, revise hypothesis 7. End by budget (new design / recommendations) ASM process to follow… https://www.asminternational.org/home Technological Tools 1. Photography and lighting 2. Optical Microscopy up to 600X 3. Scanning Electron Microscopy (SEM) over 10,000X 4. Chemical Analysis SEM/EDS (energy dispersive X-ray analysis) Spark Emission Spectroscopy (causes elements to emit light revealing their presence and concentration by distinctive wavelength signatures). Optical Microscopy Use polished and etched specimens Limited depth of field Shows individual grain structure SEM Image Individual grains Large depth of field Vacuum chamber Energy dispersive X-ray (EDS) Elements give distinct X-ray peaks, often primary and secondary Alloys Few metals are used in their pure state. Other elements are added to form alloys. Alloying provides a wide range of properties that can be manipulated by composition and heat treatment. Examples: steels and aluminum alloys. SEM Image of Alloys Constituents - Overall composition - Number of phases - Composition of each phase - Weight fraction of each phase Shape and size of the present phases Mechanical properties of an alloy depend on all phases, and on how the alloy was made (casting, heat treatments, etc.) Processing Methods Metals Cast Powder processed Cold/hot working Surface treatment Heat treatment, various methods Joining methods Processing Methods Polymers Injection molding Extrusion Blow molding Fibers Foaming Engineering Material Families Plastics Main Engineering Metals Steels Low-Carbon steels High-carbon steels Stainless steels Tool steels Cast irons Grey iron White iron Selection of Materials Selection of a material is based on many properties. Example : Jet engine turbine blade — Stiffness — High temperature strength — Thermal expansion — Thermal conductivity — Oxidation resistance — Impact resistance — Fatigue resistance — Cost  Material Properties Basic physical properties - Resistivity, dielectric constants, - Density, melting point magnetic permeability Mechanical properties Environmental interactions - Elastic modulus, yield strength, - Corrosion, wear fracture toughness Economic Thermal properties - Price and availability, - Thermal conductivity, thermal production expansion, specific heat Aesthetic Electrical/Magnetic properties - Color, texture Stress Normal Tension Normal Compression Shear Strain u L Volumetric strain = volume change per unit volume Elasticity Measurement of Elastic Modulus Nonlinear Elasticity Beyond Elasticity References 1. http://www.benbest.com/cryonics/sscurve.gif 2. http://mot.vuse.vanderbilt.edu/mse150/Fracture/Ductile/ductile.htm 3. http://www.science.smith.edu/departments/SEM/Manual99.pdf 4. http://www.corrosion-doctors.org/Forms/scc.htm 5. http://materials.open.ac.uk/mem/mem_mf8.htm 6. (http://www.asminternational.org/pdf/spotlights/jfap0502p011.pdf 7. http://corrosion.ksc.nasa.gov/stresscor.htm 8. ASM Handbook volume 11, Failure Analysis and Prevention 9. http://www.twi.co.uk/j32k/protected/band_3/jk47.html 10. http://www.ae.utexas.edu/courses/ase324_huang/Lecture15.pdf Thanks