![Fig. 85. Results for the elastic modulus, E 0, the maximum strain, e0max, and the maximum stress, r 0 max. (a) U = 0.42, (b) U = 0.15 (from Jäger and Fratzl [171, p. 1742, Figs. 5 and 6]).](/figures/fig-85-results-for-the-elastic-modulus-e-0-the-maximum-1470vf5n.webp)
![Fig. 20. (a) Stress–strain curve of collagen with three characteristic stages; I: Toe; II: linear elastic; III: failure. (b) Stress–strain curve for ventricular papillary muscle, composed of titin and collagen (courtesy of A. Jukiel, Dept. of Bioengineering, UCSD [99]).](/figures/fig-20-a-stress-strain-curve-of-collagen-with-three-1mzx9vdn.webp)
![Fig. 142. Molecular based and continuum models of red blood cell membrane. (a) Schematic drawing of the red blood cell membrane structure (not to scale). (b) Molecular based model. (c) Effective continuum membrane. (d) Large-strain response of ‘‘single-crystal’’ worm-like chain membrane (p = 8.5 nm, L0 = 87 nm, Lmax = 238 nm) for two area-preserving shear paths J1 and J2 (from Dao et al. [271]).](/figures/fig-142-molecular-based-and-continuum-models-of-red-blood-3agslnp9.webp)
Q2. What are the future works mentioned in the paper "Biological materials: structure and mechanical properties" ?
Two goals of Materials Scientists to study biological materials: ( a ) The ‘ materials ’ approach of connecting the ( nano-, micro-, meso- ) structure to the mechanical properties is different from the viewpoint of biologists and chemists, since it analyses them as mechanical systems. This approach is at the confluence of biology and nanotechnology and is already yielding new architectures that have potential applications in a number of areas, including quantum dots, photonic materials, drug delivery, tissue engineering, and genetically engineered biomaterials.
Q3. How do organic molecules influence the morphology of inorganic crystals?
Organic molecules in solution can influence the morphology and orientation of inorganic crystals if there is molecular complementarity at the crystal-additive interface.
Q4. What is the stable conformation of cellulose?
For cellulose, the most stable conformation is that each unit chair is turned 180 relative to its neighbors, yielding a straight, extended chain.
Q5. How many cracks did they produce when applied to polished shell surfaces?
for applied loads from 0.1 to more than 10 kgf the indentations failed to produce radial cracks when applied to polished interior shell surfaces.
Q6. How was the shear strength of the organic/ceramic interfaces determined?
The shear strength of the organic/ceramic interfaces of H. rufescens was determined by means of a shear test and was found to be approximately 30 MPa.
Q7. What is the reason for the lower tensile strength of proteins?
The much lower tensile strengths obtained at the meso level are due to weak links that are introduced between molecular chains, microfibrils, fibrils, and fibers.
Q8. What is the common occurrence of plastic microbuckling?
Plastic microbuckling is a common occurrence in the compressive failure of fiber-reinforced composites when loading is parallel to the reinforcement.
Q9. What is the key to the determination of the mechanical response of biological materials?
In conclusion, it can be said that the hierarchical structure of biological materials, starting at the nanometer level and continuing up to the structural dimensions, is key to the determination of the mechanical response.
Q10. What are the common configurations of polypeptide chains?
These polypeptide chains acquire special configurations because of the formation of bonds (hydrogen, van der Waals, and covalent bonds) between amino acids on the same or different chains.
Q11. What is the effect of the activation energy on the structure of different crystal faces?
Mann [31] states that this activation energy may also depend on the two-dimensional structure of different crystal faces, indicating that there is a variation in complementarity of various crystal faces and the organic substrate.
Q12. What is the average toughness of dorsolateral skin of rhinoceros?
The average toughness of dorsolateral skin of rhinoceros is 77 kJ/ m2, which is higher than the maximum toughness of rat skin, 30 kJ/m2 [256].
Q13. What are the holes in the organic nanolayer?
Holes in the organic nanolayer, which have been identified by Schäffer et al. [125], are thought to be the channels through which growth continues.
Q14. What is the secret to the ability of the gecko to remain clean and reusable?
The artificial tapes tend to quickly become laden with water or dust particles rendering them useless while the individual spatulae of the gecko are able to remain clean and reusable.
Q15. What is the role of nanoscale effects in the strength of shells?
Although nanoscale effects definitely play a role in the strength of shells, bone, and other biological materials, they by no way determine their toughness, which is established by a hierarchy of mechanisms.
Q16. What is the reason why the arteries inflate?
This makes sense since under normal blood pressure arteries inflate, causing higher strain on the inner wall of the artery (compared to the outer wall).
Q17. What is the brittleness of the ceramic phases?
These ceramic phases alone, i.e. calcium carbonate (CaCO3), are not suitable as structural materials because of their inherent brittleness.