Several posibilities ... one could be that in order to relate the output of the 'scale model' to that of the 'life-size structure', a 'life-size structure model' consisting of all relevant aspects (such as material properties, etc.) must be accurately modeled, to allow for the scale model & its interactions with the outside world to be reliably related to the 'life-size structure model'.
The key is to understand (or have a clue) about the variables that affects your phenomena. For example, if density matters, somehow you should consider it. It is important to read books throughly dedicated to scaling, for instance "Scaling" by Barenblatt. If the phenomena are already described by equations (like many fluid mechanics do) it is easier.. simply by changing length by following Pi-Buckingham theorem, you'll be able to understand which variables are relevant.
The fundamental question os what are you trying to scale?
If you are not sure of what does affect the response of the "thing", you should perform experiments or simulation varying parameters (Design of Experiment) so as to learn more on what you are studying and start creating the "Dimensionless Numbers" that are relevant for your phenomena.
If you are dealing with mainly elastic seismic response, I believe that is relevant Young Modulus, Density and Length (of course). See that, if you use exactly the same material and scale by beta=1/100 (MLT basis), your resonance frequency will be hundred times higher (1/beta) whilst your displacement 100 times lower (as beta).
Sometimes is also interesting to define a basis different from MLT (mass length time) in order to account for differences in material properties, an approach called "Distorted Similarity". It important to define the desired characteristics of your model and so verify the influence on the other parameters.
Thank you Leonardo for your help in this aspect. I will take into consideration the factors you have explained here and will get back to you on the progress of the work.
I have seen this classic movie "The Time Machine" starring Rod Taylor. There was this miniature (scaled model) of a time machine that operated like the prototype.
From that movie, I concluded that the elements, components, materials, etc. have already been decided by the Inventor. But doing the life-size prototype would be very costly and risky (if it fails).
So the inventor made first a miniature (scaled model) containing and bearing the properties of the real.
The one major issue here is whether size (from big to small) would have an effect on the functionality of the different parts and of the whole scaled machine.