Consider a rod transmitting a tensile force The following ma

Consider a rod transmitting a tensile force. The following materials are being considered: tungsten carbide, zinc alloy, polycarbonate polymer, and aluminum alloy. Using the Ashby Charts, recommend the best material for a design situation in which failure is by exceeding the strength of the material, and it is desired to minimize the weight.

Solution

To desgin a rod under a a tensile load condition a maximum strength for an optimal density needs to be considered.

Ashby\'s Young modulus over density chart is used for the purposes of material selection.

The ashby chart data (E and density) for the material options listed are,

Tungsten carbide E 500 - 1000 GPa, density >10Mg/m3 or 10000kg/m3.

Zinc alloy E 100 GPa, density 5 - 10 Mg/m3 or 7500kg/m3 (average)

Poly carbonate (polymer) E 1 - 5 GPa, density 1 - 5 Mg/m3 or 3000kg/m3

Aluminum alloy E 100 GPa, density 5 Mg/m3 (approx) or 5000kg/m3

Of all the data obtained from the Ashby chart for E vs Density we conclude,

1. Polycarbonate is the least preferred for its least tensile properties.

2. Tungsten carbide for its highest strength has an direct effect on its weight.

3. Either aluminium or zinc could be considered as they have the same strenght properties.

4. Aluminum is most prefered for its highest strength to weight ratio.