Ashby Charts (Eco-costs / Quality Charts)

Only 3 types of Ashby charts (Ashby, 2009) are provided at this webpage:

  • eco-costs versus yield strength, to select materials with a high strength and a low eco-burden
  • eco-costs versus Young’s modulus, to select materials with high stiffness and a low eco-burden
  • eco-costs versus density, to select materials with a low weight (e.g. for parts of vehicles, since transport of more weight results in more eco-burden)

The optimum choice depends on the specific application of the material. For a comprehensive explanation see (Ashby, 2009).

For a tie rod, where strength is the quality criterion,  the optimum material choice is determined by the lowest ratio of
eco-costs (euro/m2) / yield strength (MPa)

This equation results in a line of “equal eco-costs at equal strength” in Fig.7.1.

In design, however, the bending characteristics of a beam are often more important. For the bending strength of a beam, the optimum material choice is determined by the lowest ratio of
eco-costs (euro/m2) / [yield strength (MPa)]**2/3   

See Fig.7.2.

Figure 7.1 The “equal eco-costs at equal strength” line for a tie rod

Figure 7.2 The “equal eco-costs at equal bending strength” line for a beam

For bending stiffness of a beam the material choice is determined by:
eco-costs (euro/m2) / [young’s modulus (GPa)]**1/2

See Fig. 7.3

Content

Figure 7.3 The “equal eco-costs at equal bending stiffness” line for a beam

At this page below, you can find the different Ashby Charts for the yield strength, the Young’s modulus and the density of several materials in relationship to the eco-costs (per m2).

Note. The charts have been based on the eco-costs 2012, rather than the eco-costs 2023, however the relative positions are not much affected (since the graphs have a logarithmic scale). In due time the graphs will be updated.