Cells are compressible and can be regarded as a kind of coated liquid inclusion embedded in a three-dimensional elastic matrix.In the presence of far-field loading,how the coating influences the mechanical response(e....Cells are compressible and can be regarded as a kind of coated liquid inclusion embedded in a three-dimensional elastic matrix.In the presence of far-field loading,how the coating influences the mechanical response(e.g.,volume change)of the liquid inclusion remains elusive,especially when surface tension effects become significant at cell size level.We developed a theoretical model to characterize the mechanical amplification or attenuation role of coating on spherical liquid inclusions,with surface tension and liquid compressibility accounted for.We found that surface tension could increase the volumetric strain of the inclusion through decreasing its effective bulk modulus.We further found that,when there is a monotonic stiffness variation(either decreasing or increasing)from matrix via coating to inclusion,the presence of coating amplified the volumetric strain compared with the case without coating;in the opposite,when there is a non-monotonic stiffness change from matrix via coating to inclusion,the volumetric strain is attenuated by the coating.The results are useful for understanding and exploring the mechanobiological sensation of certain types of cell,e.g.,osteocytes and cancer cells.展开更多
While liquid-filled porous materials widely exist in both natural and engineering fields,their overall thermo-mechanical behaviors are influenced by the combined effects of solid skeleton,pore-filling liquid,and pore ...While liquid-filled porous materials widely exist in both natural and engineering fields,their overall thermo-mechanical behaviors are influenced by the combined effects of solid skeleton,pore-filling liquid,and pore structure.When the pores are sufficiently small(e.g.,micro/nano-scale pores),surface effects also play a significant role.Accounting for surface effects and liquid compressibility,we develop a theoretical model to predict the effective thermo-mechanical properties of liquid-filled porous materials.Idealized spherical compressible liquid inclusions distributed randomly in an elastic solid matrix are con-sidered,with two scenarios separately considered.In the first scenario,the liquid inclusions are isolated so that the liquid does not flow freely.The effective coefficient of thermal expansion(CTE)and effective bulk modulus of the two-phase material are obtained via the generalized self-consistent method.In the second scenario,the liquid inclusions are connected by micro-channels.We adopt a top-down approach(the mixture theory)to establish general thermo-mechanical constitutive relations for liquid-filled porous materials with surface effects,and then use a bottom-up(micromechanics)approach to determine the coupling coefficients(effective thermo-mechanical parameters)in these constitutive relations.Results show that the presence of surface stress at the solid-liquid interface increases the effective CTE and decreases the effective bulk modulus,especially when liquid compressibility is relatively large;however,the decrease in surface stress caused by increasing temperature weakens such effect.This research not only reveals the mechanism of thermo-mechanical coupling in liquid-filled porous materials having small pores but also provides a theoretical basis for accurate prediction of their thermo-mechanical responses in complex load environments.展开更多
基金supported by the National Natural Science Foundation of China(Grants 12032010,11532009,and 11902155)the Natural Science Foundation of Jiangsu Province(Grant BK20190382)the foundation of“Jiangsu Provincial Key Laboratory of Bionic Functional Materials”,the Foundation for the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Cells are compressible and can be regarded as a kind of coated liquid inclusion embedded in a three-dimensional elastic matrix.In the presence of far-field loading,how the coating influences the mechanical response(e.g.,volume change)of the liquid inclusion remains elusive,especially when surface tension effects become significant at cell size level.We developed a theoretical model to characterize the mechanical amplification or attenuation role of coating on spherical liquid inclusions,with surface tension and liquid compressibility accounted for.We found that surface tension could increase the volumetric strain of the inclusion through decreasing its effective bulk modulus.We further found that,when there is a monotonic stiffness variation(either decreasing or increasing)from matrix via coating to inclusion,the presence of coating amplified the volumetric strain compared with the case without coating;in the opposite,when there is a non-monotonic stiffness change from matrix via coating to inclusion,the volumetric strain is attenuated by the coating.The results are useful for understanding and exploring the mechanobiological sensation of certain types of cell,e.g.,osteocytes and cancer cells.
基金supported by the National Natural Science Foundation of China(Grant Nos.12032010,12272179,and 52102425)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX23_0351).
文摘While liquid-filled porous materials widely exist in both natural and engineering fields,their overall thermo-mechanical behaviors are influenced by the combined effects of solid skeleton,pore-filling liquid,and pore structure.When the pores are sufficiently small(e.g.,micro/nano-scale pores),surface effects also play a significant role.Accounting for surface effects and liquid compressibility,we develop a theoretical model to predict the effective thermo-mechanical properties of liquid-filled porous materials.Idealized spherical compressible liquid inclusions distributed randomly in an elastic solid matrix are con-sidered,with two scenarios separately considered.In the first scenario,the liquid inclusions are isolated so that the liquid does not flow freely.The effective coefficient of thermal expansion(CTE)and effective bulk modulus of the two-phase material are obtained via the generalized self-consistent method.In the second scenario,the liquid inclusions are connected by micro-channels.We adopt a top-down approach(the mixture theory)to establish general thermo-mechanical constitutive relations for liquid-filled porous materials with surface effects,and then use a bottom-up(micromechanics)approach to determine the coupling coefficients(effective thermo-mechanical parameters)in these constitutive relations.Results show that the presence of surface stress at the solid-liquid interface increases the effective CTE and decreases the effective bulk modulus,especially when liquid compressibility is relatively large;however,the decrease in surface stress caused by increasing temperature weakens such effect.This research not only reveals the mechanism of thermo-mechanical coupling in liquid-filled porous materials having small pores but also provides a theoretical basis for accurate prediction of their thermo-mechanical responses in complex load environments.
