A modified analysis for thermal–mechanical properties of staggered structure in biomimetic materials

The thermal–mechanical stress distributions and equivalent coefficient of thermal expansion (CTE) of the staggered arrangement of mineral platelets wrapped by soft matrix are analyzed, which exist in numerous natural biological and biomimetic materials. Two analytical models, ‘Stress model’ and ‘Displacement model’, were established from the ways of stress and displacement solution based on the modification of classical shear-lag model. Complementary finite element analysis (FEA) was used to verify the analytical models. Results reveal that, compared to ‘Displacement model’, ‘Stress model’ gives a better prediction of the stress distributions within the staggered structure referring to FEA. The equivalent CTE predicted by both models reach constant as the aspect ratio and volume fraction of platelets exceeding the critical values. Nevertheless, the relative error between the results from different models increases with the increase of the ratio of overlap to length of platelets. These provide a benchmark to the optimum design of micro/nano-structure in bio-inspired materials suffering to temperature fluctuation and applied loading.

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► Modified shear lag models for stress distribution and equivalent CTE within the staggered biocomposites are proposed.
► Different response of stress distribution is ascribed to the mismatch of elastic moduli and CTEs.
► Slender mineral platelet and high volume fraction of platelets are insensitive to thermal deformation.