TABLE OF CONTENTS In the previous chapters we mainly have used single-scale models to study material and structural behaviour at a macroscopic level. However, many natural and man-made materials exhibit an internal structure at more than one length scale. These internal structures may be of a translational nature, where the structure is more or less invariant with respect to a translation corresponding to the smallest length scale. Materials with internal structure may show also multiscale features, i.e. they may be invariant with respect to scaling. Such materials can be considered to be fractal-like, but they are not true fractals since the exponent n remains finite and the volume fraction does not go to zero even for large n. These examples of scalable structures are by no means exhaustive and many other possibilities exist. Thus, in many cases the micro structure may not be scalable and may be different at each structural level.1 Examples of different scales and their domain of application are shown in Table 18.1.
| Level | Length scale (m) | Scientific domain | Subject of manipulation | Nature of prediction |
|---|---|---|---|---|
| Quantum | 10 -12 | Computational chemistry | Molecular assembly, nuclei | Qualitative predictions |
| Nano | 10 -9 | Computational material mechanics | Molecular fragments, molecular interactions | Qualitative predictions |
| Micro | 10 -6 | Computational material mechanics | Surface interactions, orientation, anisotropy, crystals, molecular weight, free volumes | Qualitative predictions-Quantitative predictions |
| Meso | 10 -3 | Computational mechanics-computational material mechanics | Different constituents, different phases, damage | Quantitative predictions |
| Macro |
