Anodic alumina has been used widely for corrosion protection of aluminum surfaces or as a dielectric material in microelectronics applications. It exhibits a homogeneous morphology of parallel pores that can easily be controlled between 10 and 400 nm. It has been applied as a template for fabrication of the nanometerscale composite. In this study, the mechanical properties of anodic aluminum oxide (AAO) structures are measured by the nanoindentation method. The nanoindentation technique is one of the most effective methods to measure the mechanical properties of nanostructures. Using the nanoindentation method, we investigated the residual stress and mechanical properties such as the indentation modulus and hardness of the AAO structure with different-sized nanoholes. As a result, we find that the "hole effect" that changes the mechanical properties is the hole size.

Eight small scale circular reinforced concrete columns (4.5 aspect ratio) were tested under cyclic lateral load with constant axial load. The selected test variables are longitudinal steel ratio (2.017%, 3.161%), transverse steel ratio, and axial load ratio (0, 0.07, 0.15). Volumetric ratio of spirals of all the columns is 0.335~0.894% in the plastic hinge region. It corresponds to 39.7~122.3% of the minimum requirement of confining steel by Korean Bridge Design Specifications, which represent existing columns not designed by the current seismic design specifications or designed by seismic concept. The final objectives of this study are to provide quantitative reference data and tendency for performance or damage assessment based on the performance levels such as cracking, yielding, steel fracture, etc. In this paper, describes mainly failure behavior, strength degradation behaviour, displacement ductility of circular reinforced concrete bridge columns with respect to test variables.

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A model describing nanoindentation as plastic deformation resulting from a strain gradient is investigated. Using a simplified axisymmetric nanoindentation, the effective strain gradient for indentation depth is derived. The proposed indentation model is a modification of Nix and Gao’s model (1998) . To validate this approach for nanoindentation, solutions for depth-dependent hardness of single various materials such as Cu, Al, Ni are compared with experiments. Results show that the proposed model agrees well with the hardness experiments.