IsoTruss® Bike Frame Strength and Stiffness
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A finite element analysis of three different designs was performed by an independent consultant to enable direct comparison of 6-node IsoTruss® structures to equivalent metallic structures for general vehicle applications. The designs were partially optimized for bending and torsional stiffness by allowing the helical and longitudinal properties to be different. The properties used in the analysis are listed in the table below, with the results summarized in the table on the left.
The results show that rectangular and square IsoTruss® designs exceed the performance of metallic designs in bending, torsion, and axial stiffness, both separately and combined. Likewise, a 6-node double grid IsoTruss® exceeds the metallic bending stiffness and is equivalent in torsion, although not as efficient under combined loading. The 6-node double grid IsoTruss® structure was not as efficient in the combined condition because of the volume limitation imposed for this particular application.
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| Comparison Results |
| Loading Condition |
100mm X 150mm |
50mm X 50mm |
122mm diameter |
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Value,
lb-in2 |
Unit wt.,
lb/in |
Value,
lb-in2 |
Unit wt.,
lb/in |
Value,
lb-in2 |
Unit wt.,
lb/in |
| Bending: |
| Metallic |
2.25E8 |
0.4317 |
1.64E7 |
0.2855 |
7.61E7 |
0.2720 |
| IsoTruss® |
2.23E8 |
0.2850 |
1.84E7 |
0.1134 |
7.62E7 |
0.2100 |
| Torsion: |
| Metallic |
9.86E7 |
0.4317 |
1.01E7 |
0.2855 |
5.72E7 |
0.2720 |
| IsoTruss® |
5.39E7 |
0.2850 |
1.03E7 |
0.2320 |
5.78E7 |
0.2822 |
| Combined Bending & Torsion: |
| Metallic |
---- |
---- |
See Above |
0.2855 |
See Above |
0.2720 |
| IsoTruss® Bending |
---- |
---- |
1.58E7 |
0.2540 |
7.62E7 |
0.3775 |
| IsoTruss® Torsion |
---- |
---- |
1.03E7 |
0.2540 |
6.00E7 |
0.3775 |
| Axial Stiffness: |
| Metallic |
---- |
---- |
2.90E7 |
0.2855 |
---- |
---- |
| IsoTruss® Bending |
---- |
---- |
2.88E7 |
0.1410 |
---- |
---- |
| IsoTruss® Torsion |
---- |
---- |
2.78E7 |
0.1410 |
---- |
---- |
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