Multiphysical model to predict thermomechanical fracture of functional hierarchical biomimetic composites

Recent researches show that biomaterials have opened a way to inspire new microstructural designs in pursuit of ideal mechanical properties. Originated from nacre, a brick-and-mortar graded (BM-GRAD) hierarchical arrangement is proposed. To reveal the underlying cracking mechanism, multiphysical fields are investigated theoretically, including thermal, stress, and coupled thermal-stress fields. The interface damage model is further used to estimate the crack propagation direction between dissimilar materials. The Multiphysical model and general solutions of stress and displacement fields are eventually validated by experimental and numerical results. Results show that the BM-GRAD microstructure can remarkably increase the strength of the biomimetic composite under the pure stress field; however, the temperature has a high impact on structures, and a sudden cooling will highly likely cause an opening-mode failure. Moreover, although multifield leads structure to become more risky, compared with functional unbrick single gradient (GRAD) design, the BM-GRAD arrangement has a great advantage, the deflecting cracks form more easily in the BM-GRAD microstructure which progress of crack propagation is much easier to be terminated.

Automated summary

Recent researches have shown that biomaterials can inspire new microstructural designs for ideal mechanical properties. A brick-and-mortar graded (BM-GRAD) hierarchical arrangement, originating from nacre, is proposed. The cracking mechanism is investigated through theoretical analysis of multiphysical fields, including thermal, stress, and coupled thermal-stress fields. Experimental and numerical results validate the multiphysical model and general solutions of stress and displacement fields. The BM-GRAD microstructure significantly increases the strength under pure stress field, but temperature has a high impact and sudden cooling can cause opening-mode failure. Compared with functional unbrick single gradient (GRAD) design, the BM-GRAD arrangement has the advantage of easier termination of crack propagation.