TAFE NSW -Technical and Further Education Commission ENMAT101A Engineering Materials and Processes Associate Degree of Applied Engineering (Renewable Energy Technologies) Lecture 27 – Choice of materials

TAFE NSW -Technical and Further Education Commission Choice of materials EMMAT101A Engineering Materials and Processes Reference TextSection Higgins RA & Bolton, Materials for Engineers and Technicians, 5th ed, Butterworth Heinemann Ch 27 Reference TextSection

TAFE NSW -Technical and Further Education Commission Introduction (Higgins 27) EMMAT101A Engineering Materials and Processes Bicycle development - frames Ashby diagram: Specific strength vs Specific stiffness

TAFE NSW -Technical and Further Education Commission 27.2 Selection of materials (Higgins 27.2) EMMAT101A Engineering Materials and Processes The ability of the material to withstand service conditions. The method(s) by which it will be shaped. The overall cost, i.e. the cost of the material(s), with in some cases the availability of the material, and the cost of the shaping process(es).

TAFE NSW -Technical and Further Education Commission 27.3 Service requirements (Higgins 27.3) EMMAT101A Engineering Materials and Processes Mechanical properties Physical properties Chemical properties Tensile strength and specific strength Stiffness, modulus of elasticity and specific modulus Toughness and impact value Fatigue resistance Creep resistance Refractoriness Friction and wear resistance Stability in the environment Electrical conductivity Relative costs of important engineering materials

TAFE NSW -Technical and Further Education Commission 27.4 Choice of shaping process (Higgins 27.4) EMMAT101A Engineering Materials and Processes Malleability Ductility Strength The effects of temperature on the above properties Castability Machinability Can it be heat treatment? How can it be joined?

TAFE NSW -Technical and Further Education Commission 27.4 Choice of shaping process (Higgins 27.4) EMMAT101A Engineering Materials and Processes Processes Number of components required Equipment, tooling and labour costs, i.e. the capital costs to set up a process and then the running costs Processing times Material costs and availability Component form, detail such as holes required, and dimensions Dimensional accuracy and surface finish required

TAFE NSW -Technical and Further Education Commission 27.4 Choice of shaping process (Higgins 27.4) EMMAT101A Engineering Materials and Processes Changing conditions

TAFE NSW -Technical and Further Education Commission Environmental Factors (Additional) EMMAT101A Engineering Materials and Processes Disposal (bury it or burn it) Reuse (collect it intact, clean it up and use it again) Recycle (collect it as scrap and recover the material and use it somehow). Aluminium is very energy intensive to produce from ore, but as it is easy to remelt, it is particularly cost effective to recycle. Although thermoplastics can be easily recycled once separated, the bulkiness of scrap polymer products like drink bottles means that very large volumes have to be collected, which is rarely economic. Even if they can be collected, mixed thermoplastics are difficult to separate and it is probably more economic to burn the material to produce energy. In spite of their higher cost, composites are difficult to recycle because the fibre and matrix cannot easily be separated, and ceramics cannot effectively be recycled at all.

TAFE NSW -Technical and Further Education Commission Recycling (Additional) EMMAT101A Engineering Materials and Processes Ashby Diagram Recycle Fraction - Cost

TAFE NSW -Technical and Further Education Commission Energy cost (Additional) EMMAT101A Engineering Materials and Processes Ashby Diagram Energy content - Cost

TAFE NSW -Technical and Further Education Commission Selection Summary (Additional) EMMAT101A Engineering Materials and Processes Overview Advanced Design and Technology Third Edition, Norman, Cubitt, Urry and Whittaker. Longman 2000 p363

TAFE NSW -Technical and Further Education Commission EMMAT101A Engineering Materials and Processes Wikipedia: Welding Resources. HI-RESOLUTION ASHBY CHARTS : DESIGN CASE STUDIES AND TUTORIAL

TAFE NSW -Technical and Further Education Commission Glossary EMMAT101A Engineering Materials and Processes Specific (density/stress etc) Mechanical properties Physical properties Chemical properties Service conditions Duty cycle Industrial design Manufacturing energy content Recycle fraction Disposal Re-use Recycle Product life-cycle

TAFE NSW -Technical and Further Education Commission QUESTIONS: Joining of Materials Higgins Ch27, Ashby, Norman 1.Define all glossary terms 2.On the specific stiffness - strength chart (Ashby Chart), the bubbles for the metals and alloys tend to be elongated parallel to the strength axis. By considering the physical origins of Young's modulus and strength in these materials, explain why this is so. (Norman 2000) 3.Explain why bike frames are made from steel, aluminium alloy, titanium alloy and carbon fibre composites. Why are carbon fibre composites and titanium generally only found in performance racing bikes. Discuss the practicality of making a bicycle frame out of a polymer. (Norman 2000) 4.The dominant material in car bodies is steel, but there is now fierce competition from aluminium and glass fibre composites. Use the energy content and recycle fraction selection charts to compare how these materials compete with steel in a life cycle analysis of the car. (Norman 2000) 5.Briefly the relative advantages and disadvantages of timber, metal and plastic window- frames. Your answer should refer to one specific named material from each of the three groups of materials: (i) manufacturing methods employed; (ii) durability and maintenance; (iii) aesthetic factors. (Norman 2000) EMMAT101A Engineering Materials and Processes

TAFE NSW -Technical and Further Education Commission QUESTIONS: Joining of Materials Higgins Ch27, Ashby, Norman 6.Research the manufacture of large wind turbine blades. List the required performance needs, the potential materials and associated production processes. You may need to research the size, design life, factors influencing wear, storm and other damage, risk factors. (Norman 2000) 7.Old cars have metal door handles but today they are mostly plastic. Investigate the older metal door handles and their finish and compare to the modern ones. List the reasons and outline the pro’s and con’s of such a change. Describe design changes necessary when switching from a metal to a plastic. 8.Designing and making a one-off product is very different to producing many thousands. Using, as an example, a project you have made, discuss and sketch the changes which would be needed to make it viable for mass production. Your answer should compare your one-off product with a similar mass produced one in terms of: (i) choice of material, (ii) shaping and forming, (iii) joining and assembly, (iv) applying finishes, and (v) evaluating and testing. (b) Discuss the disadvantages of mass production of products. (Norman 2000) 9.Explain how a CO2-based penalty/incentive scheme (carbon-tax) would influence material and process selection for a significant area of industry (e.g. transport, housing, manufacturing etc). What are the pros and cons of this concept in terms of meeting an environmental objective? Can you think of a better way to manage environmental resources? EMMAT101A Engineering Materials and Processes