Study On Clam Shell Structure And Properties Of Layered

Shell is a common biological materials with complex microstructure and excellent mechanical properties. Is a common mollusk clams clam shells is a natural biological materials with hierarchical structure and excellent performance for high-performance composite materials and biomimetic materials design provides a new idea. Study the biological characteristics of the prototype geometry, mechanical properties, material composition is the basic prerequisite for development of biomimetic materials. Software shell as a kind of natural biological materials, due to its excellent mechanical properties and material design, and researchers are concerned about.In this paper, Yingkou clams for the study area, with a scanning electron microscope and stereo microscope observation of its microstructure; using precision cutting machine segmentation of clam shells, obtained the density distribution of different parts. Electronic universal testing machine with a clam shell on the mechanical properties were analyzed, and used finite element analysis software ansys structure corresponding to its excellent mechanical properties of simulation. Last clams film the relationship between structure and properties were discussed.Clam shells and inorganic constituents of calcite and aragonite are two-phase composition, surface of the cuticle is a layer of hardened protein, organic matter complex composition of the total weight of 5%, mainly from the insoluble polysaccharide chitin, non-glycine and alanine-rich soluble proteins, and other acidic amino acids aspartic acid-rich soluble protein composed of three kinds of biological macromolecules. Of clams and prismatic layer of nacre invasive tests and found that clams prismatic layer surface, the surface nacre are strong hydrophilic, the contact angle on the size of its surface structure, surface structure in which prismatic layer wetting properties to meet the Wenzel model . Shells of different water content compression, shear and other mechanical properties of the comparison experiment, the compression experiments, the vertical growth from the surface of maximum stress loads 54.3Mpa-90.60Mpa, and the maximum stress mainly in 55Mpa and 80Mpa so. Along the growth direction of the load, the maximum stress range between 48.5Mpa-61Mpa, as opposed to vertical loading and stability. Prismatic layer and nacreous layer of the compression strength was significantly higher than the overall maximum compressive strength, maximum strength of layered compression of the overall compressive strength of 2 times. Direction perpendicular to the surface when the load curve showed the characteristics of ceramics. In this study, precision instrument scratches on the sheet between the critical load Lc1 aragonite aragonite prismatic layer between the layer and the critical load Lc2, and compare the different water content Lc1, Lc2 changes, discussed the critical load overall mechanical properties of materials influence.Micro-friction and wear test machine using clam shells on the friction performance measurement, results show that clam shells with different roughness of sandpaper on the ground, the experimental factors on the order of the friction factors for the friction velocity, and vice types, the normal load. 1000 grit sand paper to do with friction velocity and normal load of the full experiment found that under certain conditions in the load, the friction factor increases as the sliding velocity decreases rapidly. As the sliding speed increases, the friction surface temperature, the shell material softening, shell organic matter in surface structure will be filled in between the shell material to become relatively flat smooth, micro-friction and conflict between the body surface increasingly engaging small, micro sudden relative movement between the body hindered weakened, reduced resistance to micro-cutting, in the same normal load conditions, the macroscopic friction also decreases, so that the friction factors measured lower . This trend materials with the shell structure of a certain relationship between the outermost shells stratum corneum, the hard shell of a hard protein composition, the middle layer of prismatic layer, alternating the composition of inorganic and organic matter. Early experiments, the cuticle on the raised lines will necessarily impede the growth of the conduct of friction, friction causes the increase of the friction factors measured increases. The main wear mechanism of shell material fatigue wear and adhesive wear are the two. Clam shell case with sandpaper rubbing process to plow the main, and the emergence of a slight furrow and the material transfer phenomenon.The experiment data acquisition and processing measured, the establishment of the layered structure and the shell prismatic layer and nacreous layer model. Using finite element analysis software ansys, on clam shells in the quasi-static loading and dynamic loading process of the layered structure of the stress distribution model displacement.