Interface Energy and Particle Size Effects on Effective Properties and Damage Energy Dissipation in Nanocomposites

Nowadays, since the materials science and technique have been further advanced to the characteristic size of solids in nano-size structures and nanocomposites, the interface/surface energy effect on mechanical and physical properties and damage energy dissipation of a nano-scale material or composite becomes significant and cannot be ignored. Therefore, the interface/surface energy and particle size effects on the effective properties and the damage dissipation in nanocomposites are investigated. In this research, two viewpoints of observing the interface/surface energy effect are provided in Chapters 3-5 and Chapter 6. The first is to study the interface/surface energy effect on the effective properties of the composite material upon the mechanism of micromechanics, while the second is to investigate the interface/surface energy effect on the energy dissipation due to the interfacial debonding between the particles and the matrix in the framework of the probability, such as the logarithmic normal distribution and Weibull's distribution function. In addition, another method, called Rigid-Body-Spring Model (RBSM) method, is introduced in Chapter 7. In reality, the practical construction materials usually contain multi-phases, like concrete, wood, brick, masonry, etc. Accordingly, finding an easy and convenient method to estimate the interface/surface energy effect on those materials with multiple phases, so as to replace time-consuming and complicated micromechanical operations for the multiple-phase composites, is worth investigating and developing. 3D RBSM method is easy to incorporate with our present model by adding the illustrative results based on the interface/surface energy effect into RBSM's constitutive model. In conclusion, the objective of this research is to develop the characteristic analytical expressions of the effective properties and the damage energy dissipation of the composite, especially the nanocomposite, with the interface/surface energy and particle size effects. Furthermore, since parts of the special cases/illustrations and/or formulations in the research is simplified with some assumptions, such as the axisymmetric stresses or loads, symmetric geometry of structures, fewer phases of composites, small deformations, linear elastic moduli of materials, linearized parameters, etc., more complicated conditions and/or multi-physical parameters can be modified and induced in the present analytical models in the future