Mechanical properties of Chamelea gallina shells at different latitudes

Abstract

In this work we evaluate the mechanical properties of Chamelea gallina shells, collected at various locations in the Adriatic Sea, through compression tests. We present an analytical model for the extraction of the material Young's modulus and ultimate strength, based on the approximation of the valves with a simpler geometry. The effect of porosity and the computation of the energy dissipated at fracture are also discussed. Results show a dependence of the mechanical performance on the location at which the samples were collected, i.e. latitude, and thus the environmental factors can affect the rigidity and strength of the shells. These findings confirm and integrate preliminary results published in a previous work. Graphical Abstract: KeywordsClam shells, abiotic factors, aragonite, analytical modelling, fracture.

Investigation of failure mechanisms of nacre at macro and nano scales

“…being 𝑃𝑃 the load and 𝑤𝑤 𝑚𝑚𝑝𝑝𝑚𝑚 the fracture displacement during the micro-cantilever test, respectively. Thus the right part of equation ( 12) is 0.075~0.1, smaller than left part, where 𝒯𝒯 𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑝𝑝𝑖𝑖𝑝𝑝𝑐𝑐𝑖𝑖 is 8.3~11.1 N/m from the micro-cantilever test in section 3.1 and 𝒯𝒯 𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑎𝑎𝑝𝑝𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖 is estimated to be 110 N/m from the previous research [34]. As shown in Figure 5(d), The normalized energy release rate is plotted as a function of the angle between the incident crack and interface.…”

An Ingenious Microstructure Arrangement in Deep-Sea Nautilus Shell against the Harsh Environment

“…The fracture toughness can be estimated using the fracture energy ( G ), that is, the energy required for crack propagation per unit area. It can be described as where A and P are the fracture area and load, respectively, and δ max is the displacement corresponding to the fracture load. According to eq , the fracture energy for these two groups is calculated, and the value (0.89 KJ/m 2 ) for Up is more than three times that (0.26 KJ/m 2 ) for Down (Figure f).…”

“…The fracture toughness can be estimated using the fracture energy (G), that is, the energy required for crack propagation per unit area. It can be described as 39…”