Sintered powder metals have found wide applications in industry. However, the constitutive description under complex loading conditions is an open issue. In the present work, the inelastic deformation mechanisms of sintered iron are investigated using nano-indentation technique. With help of the finite element method, the material behaviour of powder particles can be identified from extensive nano-indentations. Furthermore, the micro-hardness of pre-strained specimens has been investigated as a function of the macro strains up to 14%. Nano-indentation measurements provide a linear correlation between the micro strains in power particles and macro deformation. Ca. 55% of total inelastic deformations are contributed from powder particles and the rest is caused by the void growth as well as micro crack propagation. In sintered metals the micro porosity plays an important role in inelastic deformations.

Based on a brief introduction of the operational principle of terrestrial 3D LiDar, this paper describes some typical defects detection methods of security distance in the overhead transmission line with living examples. These tests are realized by the Z+F Imager 5010 terrestrial 3D LiDar and Polyworks. The research results show that terrestrial LiDar technology can achieve the defect evaluation of defect detection of security distance in the overhead transmission lines. And this technology has many advantages, such as portable, security, intuitive and high precision.

The paper briefly reviews the operational principles and commercialized conditions of airborne three-dimensional (3D) LiDar and terrestrial 3D LiDar. And then the representative functions of 3D LiDar that are developed for the operation and maintenance of overhead transmission lines (OTL) are described in detail. Besides, the problems associated with the process of applying 3D LiDar to OTL are analyzed. It is pointed out that it is necessary to make improvement to several aspects, including new functions development, standardization of application approaches and the simplification of data processing.