Data Reduction And Error Analysis For The Physical Sciences

The feasibility of high field magnet applications of the twisted stacked-tape cabling method with 2G YBCO tapes has been investigated. An analysis of torsional twist strains of a thin HTS tape has been carried out taking into account the internal shortening compressive strains accompanied with the lengthening tensile strains due to the torsional twist. The model is benchmarked against experimental tests using YBCO tapes. The critical current degradation and current distribution of a four-tape conductor was evaluated by taking account of the twist strain, the self-field and the termination resistances. The critical current degradation for the tested YBCO cables can be explained by the perpendicular self-field effect. It is shown that the critical current of a twisted stacked-tape conductor with a four-tape cable does not degrade with a twist pitch length as short as 120 mm. Current distribution among tapes and hysteresis losses are also investigated. A compact joint termination method for a 2G YBCO tape cable has been developed. The twisted stacked-tape conductor method may be an attractive means for the fabrication of highly compact, high current cables from multiple flat HTS tapes.

https://iopscience.iop.org/article/10.1088/0953-2048/25/1/014011/pdf

HTS twisted stacked-tape cable conductor

By means of Non-Uniform Rational B-Splines (NURBS) curves, it is possible to describe arbitrary shapes with holes and discontinuities. These peculiar shapes can be taken into account to describe the reference domain of several nanoplates, where a nanoplate refers to a flat structure reinforced with Carbon Nanotubes (CNTs). In the present paper, a micromechanical model based on the agglomeration of these nanoparticles is considered. Indeed, when this kind of reinforcing phase is inserted into a polymeric matrix, CNTs tend to increase their density in some regions. Nevertheless, some nanoparticles can be still scattered within the matrix. The proposed model allows to control the agglomeration by means of two parameters. In this way, several parametric studies are presented to show the influence of this agglomeration on the free vibrations. The considered structures are characterized also by a gradual variation of CNTs along the plate thickness. Thus, the term Functionally Graded Carbon Nanotubes (FG-CNTs) is introduced to specify these plates. Some additional parametric studies are also performed to analyze the effect of a mesh distortion, by considering several geometric and mechanical configurations. The validity of the current methodology is proven through a comparative assessment of our results with those available from the literature or obtained with different numerical approaches, such as the Finite Element Method (FEM). The strong form of the equations governing a plate is solved by means of the Generalized Differential Quadrature (GDQ) method.

Free vibration analysis of arbitrarily shaped Functionally Graded Carbon Nanotube-reinforced plates

Nano-cutting fluids are the mixtures of conventional cutting fluid and nanoparticles. Addition of the nanoparticles can alter wettability, lubricating properties, and convective heat transfer coefficient (cooling properties) of nano-cutting fluids. In the present work, nano-cutting fluid is made by adding 1% Al2O3 nanoparticles to conventional cutting fluid. The wettability characteristic of this nano-cutting fluid on a carbide tool tip is measured using the macroscopic contact angle method. Comparative study of tool wear, cutting force, workpiece surface roughness, and chip thickness among dry machining, machining with conventional cutting fluid as well as nano-cutting fluid has been undertaken. This study clearly reveals that the cutting force, workpiece surface roughness, tool wear, and chip thickness are reduced by the using nano-cutting fluid compared to dry machining and machining with conventional cutting fluid.

/pdf/nano-cutting-fluid-for-enhancement-of-metal-cutting-4ze3i8f1k0.pdf

Nano-Cutting Fluid for Enhancement of Metal Cutting Performance

Journal of Materials Processing Technology: Preface

Large rotation analysis of elastic thin-walled beam-type structures using ESA approach

Buckling analysis of thin-walled functionally graded (FG) sandwich box beams is investigated. Material properties of the beam are assumed to be graded through the wall thickness. The Euler-Bernoully beam theory for bending and the Vlasov theory for torsion are applied. The non-linear stability analysis is performed in framework of updated Lagrangian formulation. In order to insure the geometric potential of semitangental type for internal bending and torsion moments, the non-linear displacement field of thin-walled cross-section is adopted. Numerical results are obtained for FG sandwich box beams with simply–supported, clamped–free and clamped–clamped boundary conditions to investigate effects of the power-law index and skin-core-skin thickness ratios on the critical buckling loads and post-buckling responses. Numerical results show that the above-mentioned effects play very important role on the buckling analysis of sandwich box beams.

/pdf/buckling-analysis-of-thin-walled-functionally-graded-2h3vfra39s.pdf

Buckling analysis of thin-walled functionally graded sandwich box beams

Nonlinear buckling behaviours of thin-walled functionally graded open section beams

AISI 316Ti (1.4571) steel—Mechanical, creep and fracture properties versus temperature

In this paper some experimental results and analyses regarding the behavior of AISI 420 martensitic stainless steel under different environmental conditions are presented. That way, mechanical properties like ultimate tensile strength and 0.2 percent offset yield strength at lowered and elevated temperatures as well as short-time creep behavior for selected stress levels at selected elevated temperatures of mentioned material are shown. The temperature effect on mentioned mechanical properties is also presented. Fracture toughness was calculated on the basis of Charpy impact energy. Experimentally obtained results can be of importance for structure designers.

Goran Turkalj

Papers

Large rotation analysis of elastic thin-walled beam-type structures using ESA approach

Buckling analysis of thin-walled functionally graded sandwich box beams

Nonlinear buckling behaviours of thin-walled functionally graded open section beams

AISI 316Ti (1.4571) steel—Mechanical, creep and fracture properties versus temperature

Martensitic stainless steel AISI 420—mechanical properties, creep and fracture toughness