In the field of oil & gas drilling engineering, the Rotary Steerable System (RSS) is very widely used in directional drilling, the whole drillstring is rotated from the surface by a hydraulically driven top drive. In this paper we analysis of the dynamic model of the Rotary Steerable System (RSS) with a single stabilizer and flex-sub and takes a method of the longitudinal and transverse bending continuous beam method to analyse the stress of RSS with the flex-sub.

This paper presents a way to model the rotational constraint between beam elements in 3-D space. Beam elements are models used to simulate the behavior of slender objects. Such objects can be found for e.g. in bridges, space structures, robots, and networks of fibers (paper, cloth, biological tissue, etc). In many cases, beam elements are welded or bonded together. To model this bonding, the relative displacements and rotations shall be limited at the contact point using appropriate constraints.

The paper is concerned to the computation of eigenfrequencies of single-walled carbon nanotubes (SWCNTs). Classical treatment, where the nanotube is approximated by beam theory, is replaced by the nonlocal theory of beam bending. The eigenfrequencies are computed by combination of analytical, as well as numerical methods for four types of boundary conditions. The results can be used for determination of Young’s modulus of homogenized SWCNTs from experimental measurements.

In this paper, a numerical model for the analysis of bond-slip occurring in concrete filled steel tube (CFT) columns is introduced. The introduced model considers the bond-slip effect by incorporation of the equivalent steel stiffness. Finally, the validity of the introduced numerical model is verified by comparing the experimental data with the analytical results for CFT columns subjected to axial force and bending moment.

The traditional concepts on severe accident mitigation weren't seriously challenged until the occurrence of Fukushima accident on 2011, suggesting the structural behavior had not been appropriately assessed. Therefore, the paper tries to address the structure-related issue on determining whether structural safety can be maintained or not with the effect of various water levels and internal pressures created from core meltdown accident. The creep and plastic damages are interacted with each other