UNIVERSITY OF SOUTH AUSTRALIA
5:48 PM15
ENGINEERING MATERIALS TECHNICAL WRITING REPORT
Brief
The aim of this activity is to solve simple engineering and material selection problems, and to develop writing and communication skills.
A high performance racing catamaran is being designed. The total width of the catamaran is 7m, and the maximum compression load on the mast is expected to be 1000kg. Maximum deflection of the beam should not exceed 50mm. The load on the 15m wire stays is expected to be a maximum of 600kg each. The mass of the hulls and mast together is 500kg (not including the beam and stays). The catamaran will be lifted out of the water each day by a crane using a single lifting point. The lifting wire must be strong enough to lift the combined weight of the hulls, mast, beam and stays. You must:
1. Specify the material to be used for the beam, and calculate the diameter. Assume the beam is cylindrical with 1000kg load applied in the middle.
2. Specify the material to be used for the wire stays, and calculate the diameter.
3. Specify the material and diameter to be used for a wire to lift the catamaran out of the water.
Choose appropriate safety factors for each.
Figure 1. Diagram of components to be designed.
Remember:
1. Your report should contain the following sections:
Title and authors
Executive Summary (approx. 100 words)
Discussion (approx XXXXXXXXXXwords for each design element)
Conclusions (approx. 100 words)
References (approx. 6-10)
Appendix (include all calculations/tables etc for each element)
2. You should discuss why you choose certain materials and sizes for the application instead of the alternatives listed below in Table 1.
3.
Material
Yield Stress (MPa)
Tensile (or Compressive) Stress (MPa)
Elastic (or Flexural) Modulus (GPa)
Density (kg/m3)
Steel
200
307
200
7890
Aluminium
70
110
70
2700
Coppe
150
180
110
8960
Titanium alloy
880
950
110
4510
Silicon Nitride
820
830
310
3440
Oak
40
70
11.3
780
Fi
eglass
235
250
24
1900
Prepreg Ca
on fi
e
1800
1860
150
1600
Concrete
3
3
4.5
2200
Glass
70
75
80
2200
Reinforced Polyca
onate
85
90
23
1200
Table 1. Properties of materials to be selected from.
Some useful equations for bending (also see Ch 12 in textbook)
Stress for a rectangular section beam
Stress for a circular section beam
Deflection for a rectangular section beam
Deflection for a circular section beam
RENG1005 Engineering Materials Technical Report
Marking Scheme
Student name:
Assessable element
Comments
Marks
Word count
Not including Title, author and references
Marks deducted if outside the recommended range.
2
Sections
The report should be suitably formatted and address all section headings
Title and autho
Executive Summary
Discussion
Conclusions
References
Appendix
3
Technical content
The report should demonstrate knowledge of the properties and use of materials with relevance to the chosen topic. Materials selection criteria should be addressed in detail. The quality of the referencing will also be assessed.
Possible examples of relevant properties include stiffness, toughness, durability, density, strength-weight ratio, cost, ease of manufacture etc
12
Appendix
Calculations to be accurate, suitably presented and answers valid
3
Total
/20
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