ENGINEERING TRIPOS PART IA - 2012/2013

PAPER 2 - STRUCTURES and MATERIALS

Materials

Leaders: Dr H.R. Shercliff/Dr A.E. Markaki/Dr. A. Kabla

Timing: Weeks 1-8 Lent term and weeks 1-3 Easter term.

Structure: Lent: 12 lectures (1 or 2 per week); Easter: 8 lectures (2 or 3 per week)

AIMS

The aims of the course are to:

• Introduce the material properties and failure mechanisms most relevant to mechanical design and engineering applications.
• Relate properties to atomic, molecular and microstructural features, using appropriate mathematical models.
• Develop systematic strategies for material and process selection for a given component.

OBJECTIVES

As specific objectives, by the end of the course students should be able to:

• Describe the atomic and microstructural characteristics which control the important properties of engineering materials, and to interpret material property charts
• Explain briefly the origin of the elastic modulus for each class of engineering materials (metals, ceramics, polymers) and analyse the moduli of composites
• Understand the mechanisms for plastic flow in metals, and the ways in which the strength can be enhanced via the microstructure
• Describe and analyse the stress-strain response of simple geometries under uniform mechanical and thermal loads, distinguishing between true and nominal stress and strain
• Understand a systematic strategy for materials selection for a given component, and use the Cambridge Engineering Selector software to find material data and select materials
• Choose materials from material property charts using simple calculations (e.g. stiffness and strength of beams at minimum weight)
• Choose primary shaping process from process attribute charts, and estimate the cost of manufacture for batch processing
• Understand the environmental impact of materials in the life cycle of products
• Apply fracture mechanics principles to metals and Weibull statistics for fracture to ceramics, and describe mechanisms of failure in all classes of material
• Describe and model fatigue fracture in metals
• Describe the origins of friction and wear in engineering
• Understand the principal mechanisms of environmental degradation of metals and polymers (oxidation, corrosion) and know the common methods for protection of components

SYLLABUS (Book References)

1. Introduction (1L, Dr H.R. Shercliff)

• Classes of engineering materials; materials in design (design-limiting properties); life-cycle of materials. (1) Chap. 1,2,20; (2) Chap. 1,3; (3) Chap. 30; (4) Chap. 27

2. Elastic Properties of Materials (5L, Dr H.R. Shercliff)

• Elastic stiffness in design: analysis of stress and strain, thermal stress. (1) Chap. 4,12; (3) Chap. 3; (5) Chap. 7
• Young's modulus and density: measurement, data and materials property charts: introduction to Cambridge Engineering Selector software; stiffness-limited component design. (1) Chap. 4,5; (2) Chap. 3-6; (3) Chap. 3,7; (5) Chap. 7
• Microstructure of engineering materials I: Atomic/molecular structure and bonding; physical basis of elastic modulus and density. (1) Chap. 4; (3) Chap. 4-6; (5) Chap. 2-4
• Manipulating properties I: Elastic properties in composites and foams. (1) Chap. 4; (2) Chap. 13; (3) Chap. 6

3. Plastic Properties of Materials (4L, Dr H.R. Shercliff)

• Tensile and hardness testing, measurement of strength, data and material property charts: strength-limited component design. (1) Chap. 6,7; (2) Chap. 3-6; (3) Chap. 8,11,12,31; (4) Chap. 4-6; (5) Chap. 7
• Microstructure of engineering materials II: Atomic basis of plasticity, dislocations. (1) Chap. 6; (3) Chap. 9; (5) Chap. 8
• Manipulating properties II: Strengthening mechanisms in metals. (1) Chap. 6,14; (3) Chap. 10; (5) Chap. 8,12

4. Process Selection and Environmental Impact in Design (2L, Dr H.R. Shercliff)

• Selection of manufacturing process and cost estimation for batch processes. (1) Chap. 18; (2) Chap. 7,8
• Environmental impact and life cycle analysis of materials. ((1) Chap. 20; (2) Chap. 16; (5) Chap. 21

5. Fracture and Fatigue (5L, Dr A.E. Markaki)

• Toughness, fracture toughness and fatigue fracture. Micromechanisms of fracture and fatigue in metals. Weibull statistics for ceramic fracture. Polymer failure mechanisms. (1) Chap. 6,8-10; (3) Chap. 13-19; (4) Chap. 18,23; (5) Chap. 9

6. Wear, Corrosion and Natural Materials (3L, Dr. A. Kabla)

• Friction and wear. (1) Chap. 11; (3) Chap. 28,29
• Oxidation and corrosion. (1) Chap. 17; (3) Chap. 24-27; (5) Chap. 16

REFERENCES

Please see the Booklist for Part IA Courses for details of the references for this module.