R3DC Report 2-08
Introduction
R3 Description
Geometry
Material Specifications
| Material | Youngs Modulus | Density |
| MPa | ||
| Polyeurethane Foam FR-3700 | 140 | 240 |
| Hexacell with holes | ||
| Carbon Fiber Rods | 210 | 580 |
Specific part Drawings
Endplate Deflection
Point Load Deflection
A simple calculation based on the definition of Young's modulus can yield an order of magnitude level estimate for the deflection of an endplate made from Aluminum. According to the definition of Young's modulus
where
- Young's Modulus for Aluminum
- point force/load
- width of the endplate
- deflection of endplate due to point force
- length of the endplate
- thickness of the endplate
A deflection of 6 mm is expected for a 5 cm thick Aluminum endplate, after solving the above equation for and inserting the given values. If a 5 cm thick stainless steel endplate were used, the deflection would drop a factor of 3 from 6 mm to 2 mm due to the linear dependence of the deflection on Young's Modulus. The previous work of Kevin Folkman led to a similar conclusion.
Distributed Load Deflection
Distributed load FEA
In addition to validating the FEA analysis with hand calculations, the above results also reveal the challenge of reducing the endplate deflection using stiffer Materials due to an essentially linear dependence of the deflection to Young's Modulus. The cubic dependence of the deflection on the thickness of the endplate, however, can be used to reach the minimum endplate deflection criteria of 50 instead of using stiffer material. Increasing the endplate thickness comes at the cost of increasing the end plate mass. As a result, composite materials were considered in order to minimize weight.
Carbon Rod Buckling
Compression
Buckling Load Threshold
Buckling FEA
=3-D Analysis