Torsion of a racing car aerofoil

Torsion of a racing car aerofoil.

An aerofoil is manufacturing from a carbon fibre reinforced polymer skin thickness 1.5mm  with the geometry, lengths and areas given in the accompanying assignment XL spread sheet containing a corresponding SET No. ranging from 1 to 14.

use SET No 6.

A schematic of the cross-section is shown in fig A1. Using this information complete the following tasks stated below and answer the questions at the end of the tasks.

 

Position Length (mm)
AB
BC
CD
DE
EF
FG
GH
HA
CG

 

Area Size (mm2)
ABH
BCGH
CDFG
DEF

 

 

 

 

 

Table A1, for your actual lengths and areas see your set number in the spreadsheet at the appendix.

 

 

 

 

 

 

 

 

 

 

Assume for the skin the following properties, Mean E fibre = 350 GPa, volume fraction = 65%, design strain 0.5%, and effective length is 1.6m.

Task 1 (40%)

Assuming the car can achieve a maximum speed of 220 mph with a lift coefficient of 1.6 for the aerofoil and the centre of twist is approximately is 15% of the chord length AE;determine the maximum angle of twist and shear stress induced in the aerofoil for this case.

 

Task 2 (10%)

The actual aerofoil however has closed ends with a small plate of the same material. Estimate how this will change your predicted answer and indicate the positions along the length were this is most affected using a simple sketch.

Task 3 (25%)

If under race condition the section is subject to an impact at the mid-point between the end plates which damages section FG. Estimate the increase in angle of twist and the maximum induced shear stress due this impact.

Torsion of a racing car aerofoil Supplementary questions

  1. If the aerofoil was manufactured from aluminium comment on how the behaviour of the aerofoil would react to the conditions in tasks 1 to 3 inclusive (10%)
  2. Describe how the “centre of twist” affects the loading (5%)
  3. Describe briefly how the composite part would be joined and how you could estimate the stress in the adhesive. (10%)

 

 

LOs for this work are as follows:

Demonstrate a comprehensive understanding of the scientific principles of mechanical and related engineering disciplines (US1m

Demonstrate an awareness of developing technologies related to mechanical engineering. (US4m)

Submission method

 

On completion of your task you will need to upload your solution via the moodle link provided by your module tutors.

 

Appendix

 

Position Length(mm) DIMENSIONS
Area Size (mm2) Area Size (mm2)
AB 78 ABH 960 AB 75 ABH 945
BC 86 BCGH 2700 BC 83 BCGH 2685
CD 60 CDFG 2300 CD 57 CDFG 2285
DE 38 DEF 160 DE 35 DEF 145
EF 38 EF 35
FG 64 FG 61
GH 92 SET 1 GH 89 SET 5
HA 80 HA 77
CG 36 CG 33
AB 82 ABH 976 AB 72 ABH 930
BC 90 BCGH 2716 BC 80 BCGH 2670
CD 64 CDFG 2316 CD 54 CDFG 2270
DE 42 DEF 176 DE 32 DEF 130
EF 42 EF 32
FG 68 FG 58
GH 96 GH 86
HA 84 SET 2 HA 74 SET 6
CG 40 CG 30
AB 86 ABH 991 AB 68 ABH 918
BC 94 BCGH 2731 BC 76 BCGH 2658
CD 68 CDFG 2331 CD 50 CDFG 2258
DE 46 DEF 191 DE 28 DEF 118
EF 46 EF 28
FG 72 FG 54
GH 100 SET 3 GH 82
HA 88 HA 70 SET 7
CG 44 CG 26

The grading system and assessment criteria are those as described in the module handbook in sections 11, 13 and 14.

 

 

Torsion of a racing car aerofoil