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MSE 5090: Case Studies in Material Selection
Week 3 - Material Selection Process
Weighted Property Index Methods - Demonstration Problem
go to WEEK 3 Problem 1 2 3 4 5 Demo Online Course Support
MSE 5090: Case Studies in Material Selection
Week 3 - Material Selection Process
Weighted Property Index Methods - Demonstration Problem
(a) List the key requirements of a material to be used to construct a gear case for the engine of a turboprop aircraft.
(b) For four candidate materials, tabulate the values of the relevant properties.TABLE Q50.1 PROPERTIES OF FOUR CANDIDATE MATERIALS FOR THE GEAR CASE OF A TURBOPROP AIRCRAFT ENGINE
| Material | p
(kg m-3) |
E
(GPa) |
UTS
(MPa) |
SS
(MPa) |
| Magnesium | 1827 | 45 | 234 | 117 |
| Short boron fiber
reinforced epoxy resina |
2132 | 69 | 258 | 155 |
| Continuous boron fiber
reinforced epoxy resina |
2132 | 190 | 1241 | 69 |
| Aluminum | 2700 | 71 | 105 | 75 |
| Material | a
(10-6 ° C-1) |
E/p
(106 m) |
UTS/p
(l03 m) |
SS/p
(l03 m) |
| Magnesium | 25.20 | 2.51 | 13.06 | 6.53 |
| Short boron fiber
reinforced epoxy resina |
3.20 | 3.30 | 12.33 | 7.41 |
| Continuous boron fiber
reinforced epoxy resina |
4.14 | 9.08 | 59.34 | 3.30 |
| Aluminum | 24.00 | 2.68 | 3.96 | 2.83 |
(a) The key requirements of a gear
case material are as follows:
·
High ultimate tensile strength, UTS
·
Low density, p
·
High tensile modulus, E
·
High shear strength, SS
·
High specific stiffness (= EIp)
·
High specific tensile strength (= UTS/p)
·
High specific shear strength (= SSIp)
·
Good corrosion resistance
·
Suitability for easy machining and molding
(b) The values of the relevant properties
of four candidate materials for this application are given in Table Q50.1.
REFERENCE:
1.Lewis , G. Selection of Engineering Materials, Prentice Hall , 1990, pp 394-395
Last update 9-12-98