Originally posted by Kolchak
And what? Snip, snip.
Ah, I think I WILL jump all over you on this one, you fell into my trap!
Although specific modulus is a primary characteristic of any material, it's the specific strength (within each class of material) that makes ALL the difference in the world. Specific strength can vary by an order of magnitude (or more), specific modulus can vary somewhat (more so for elastomers (say 200%), less for plastics (say 20%), and even less for metals (say 10%)). It is the strength (specifically yield or allowable) of any material that determines properties such as axial, shear (i. e. puncture AND wear resistance), and torsional properties. Specific modulus only relates to elongation (i. e. stiffness of a material to deflect under load (the "stress-strain" curve (Ever seen one? Do you know the difference between an engineering stress-strain curve and the true stress-strain curve? Do you know the reality of stress-strain curves (rarely truly linear, thus it's VERY misleading (in general) to assign a single value for E (usually defined as the tangent modulus (slope of the stress-strain curve at zero load), in general the secant moduli should be used for the design envelope))))). Metals/plastics are usually characterized with a single value of E, due to the fact that the stress-srain curve is approximately linear within its working range, elastomers however are a different beast altogether (basically how they are confined and their aspect ratio determines the initial modulus, but the modulus also changes substantially with % breaking load). Take a rubber band for example, stretch it, it does get stiffer as you stretch it (in engineering stress-strain terms), now doesn't it? Also, there are different moduli depending on how the load is applied (Bulk modulus (K), shear (G) modulus, tensile (E, i. e. Young's) modulus, and Poisson's (v) ratio define an isotropic material (although you only need 3 of these to determine the 4th), few (if any) materials are TRULY isotropic). Maybe you know this already? Although, by what you have already said thus far, this does not seem to be the case?
I do have a LITTLE experience (33 years in fact, as a physical and numerical modeller, structural engineer, hydraulic engineer, coastal engineer, and naval architect). As an undergrad I was best-of-class in structural and hydraulic engineering, subjects I have pursued vigerously to this very day, and I will continue to do so until I'm dead (notwithstanding you). Everything I have ever designed has worked properly (or in the case of timber/congrete/steel structures is still standing AND functional). I have dealt with all manner of metals/plastics/elastomers in performing my job responsibilities in that time (whether model or prototype or finished product). I have worked for the leading US government civil engineering laboratory. I currently work (as a contractor) for this same laboratory (ERDC) on a military project which will use high strength aluminum, elastomers, and high strength synthetic fibers (Vectran, Kevlar, Twaron, Technora, Spectra, Dyneema, M5, Zylon to name drop, I can't tell you which one of these (or possibly several) we WILL use on this project (although I've already selected the candidate fiber (and/or fibers) after a rigerous testing, analysis, and ranking procedure specific to our design criteria)). We've already used Kevlar 100 on two scale models of our "structure." So you could say I am the plastics engineer on this project, no formal training, but then again I'm self taught in naval architecture, it's no biggie really, it's all engineering afterall, now isn't it? Another hat to wear, I kind of like being a master of all trades. And really, I do know a lot about high strength synthetic fibers, go ahead ask me anything, if anyone can answer it, I believe I can. So I do think I know what I'm talking about, just as certain that I know that you don't know what you're talking about. Ever drive down a concrete highway? Notice the rutting of the road surface, what do you think causes this? RUBBER wheels on the CONCRETE surface perhaps? Which one is HARDER? I'll give you ZERO guesses, seeing as you don't know what you're talking about! True, each surface has a different wear rate but they BOTH wear, how can two materials abrade one another and each not wear, if one wears then both must wear (albeit at DIFFERENT rates).
You do know what anodizing does to the metal, it hardens it, i. e. the STRENGTH (not the modulus) of the surface layer is improved (in addition to corrosion resistance and dying potential due to hexagonal nature of the surface molecules (ah, you gotta like wikipedia (for general info))). In regard to coated polycarbonate, just how thick do you think these layers are? My guess is a few mils. Not a whole lot of protection considering the potential duty cycle, now is it? So there you have it, the underlying plastic will determine the long term durability/usability of the product, given the likely environment the nano will see.
I don't know where this is going, for you really can't win this one, you can try, but you're really starting to BORE me!