Structural Capability
The photograph below illustrates the high strength-to-weight ratio that IsoTruss™ grid structures exhibit. These trusses have the ability to resist relatively high loads compared to their own weight. Here, four 8-node trusses all together weighing less than 1 lb. (.45 kg), support a reinforced concrete block weighing approximately 11,600 lb. (5262 kg). A composite IsoTruss™ structure of equivalent strength weighs only 1/12th the weight of a steel structure. In other words, a 100 lb. (45.4 kg) steel pole could be replaced with a 9 lb. (4.1 kg) composite IsoTruss™ structure.
 

Properties & Behavior
Comparison Results
Loading Condition 100mm X 150mm 50mm X 50mm 122mm diameter
  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 ---- ----

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.
Steel Aluminum Uni-Carbon
 E, Msi 29.0E6  E, Msi 10.5E6  E11, Msi 20.1E6
 G, Msi 11.0E6  G, Msi 4.0E6  E22, Msi 1.2E6
 v 0.32  v 0.33  G12, Msi 5.57E5
 p, lb/in3 0.283  p, lb/in3 0.100  v12 0.259
   v23 0.36
 G23, Msi 4.42E5
 p, lb/in3 0.05687