Two-Scale Analysis for the Mechanical Properties of Nano-Composites with Non-Linear Interface

Combining the cohesive zone elements into the two-scale homogenization method, the effective mechanical properties of nano-composites with a non-linear interface are analyzed. A periodic microscopic representative volume element (RVE) is modeled using a four-phase composite composed of matrix, nano-tube, bonded, and debonded interfaces. The debonded interface is simultaneously considered as bilinear plastic material satisfying the von Mises conditions in the presented algorithm, and a simple elastic–plastic constitutive model is established to study the non-linear effective elastic properties of nano-composites and equivalent stress for interface and nano-tube. The predicted results show a strong non-linear dependence of the effective mechanical properties on the interfacial modulus and yield stress.

Energy-Based Debonding Model for Steel-Concrete Composite Structures

This paper present a energy-based modelling approches for interfacial debonding between steel and concrete. Steel-concrete composite structural member is considered as a generalized elastic body with both the applied load and the interfacial shear stress acting as boundary stresses, and the debonding is modeled as crack propagation along the interface. The energy relationship is discussed in the process of debonding and an energy-based criterion for steel-concrete composite structure is proposed. Following, the debonding process is analyzed through energy-based criterion. The analysis is first performed for special case with constant shear stress along debonded interface, and then for the general case with shear stress softening in the debonded zone. A direct correspondence between energy-based and strength-based analysis can be established for arbitrary softening behavior along the interface. Specifically, through the proper definition of effective interfacial shear strength, the conventional strength-based approach can be employed to give the same results as the much more complicated energy-based analysis.