CAE · COMPOSITE OPTIMISATION
Simulation-led optimisation and experimental validation of a CFRP motorsport suspension pull rod, investigating laminate thickness and ply orientation under tensile and torsional loading.
GENESIS GRM · MATLAB · ASTM TESTING · CFRP
01
The front suspension pull rod was assessed under a severe braking condition. Vehicle load transfer was used to determine the axial force transmitted through the pull rod, while an eccentric load case provided a representative torsional moment.
02
VTC401 CFRP was experimentally characterised before simulation so that the material model was based on measured rather than purely supplier-derived properties. Tensile and compression testing was performed at 0° and 90° orientations.
INPUT
Experimental results were consolidated into a MAT8 material card for the anisotropic composite model used in Genesis GRM.
| Property | Value |
|---|---|
| E 1 | 55.3 GPa |
| E 2 | 55.4 GPa |
| G 12 | 26.5 GPa |
| ν 12 | 0.05 |
| Density | 1.80 g/cm³ |
| Ply thickness | 0.285 mm |
The measured card also included longitudinal, transverse and shear strength values for optimisation and structural assessment.
03
The optimisation objective was minimum mass. Tensile analysis varied laminate thickness between 3 and 10 plies, while torsional optimisation explored ply orientation between −90° and +90° in 5° increments.
04A
Genesis GRM was used to minimise laminate thickness while retaining the required response under the calculated tensile load. The optimisation converged on a three-ply laminate for the tensile case.
04B
The torsional load case changed the optimum fibre strategy. Off-axis plies were required to carry shear more effectively, producing a layup dominated by ±45° orientations around a central 0° ply.
05
A CNC-machined aluminium split mould was developed to manufacture the hollow aerofoil pull rods. The mould incorporated controlled alignment and jacking features, while an internal vacuum-bagging method was developed to consolidate the laminate through the component's closed section.
06A
Manufactured pull rods were physically tested in tension to assess whether the laminate behaviour observed experimentally followed the expected influence of fibre orientation.
| Layup | Peak load | Observed response |
|---|---|---|
| 0° | ≈ 36 kN | Higher stiffness · brittle fibre-dominated failure |
| 45° | ≈ 17 kN | Lower tensile capacity · progressive shear response |
06B
The test results showed a clear difference in failure mechanism. The 0° specimen failed abruptly through the fibre-dominated load path, whereas the 45° specimen exhibited greater delamination and matrix cracking associated with off-axis loading.
The physical testing supports the expected directional behaviour of the laminates, while the limited sample count means the results should be interpreted as validation of the engineering trend rather than a statistically complete correlation study.
07
Experimental characterisation provided the material inputs used to build the anisotropic Genesis GRM model.
A 0°-dominant laminate suited tensile loading, while ±45° fibres became important when torsional shear was introduced.
The project linked analytical loading, experimental inputs, simulation, manufacturing and physical component testing.
“This project demonstrated that composite optimisation cannot be separated from material characterisation and manufacturing. The confidence placed in the CAE model depended directly on the quality of the experimental inputs and the ability to reproduce the intended laminate physically.”