Validation of a 20 m Wind Turbine Blade Model

In the projects Smartblades and Smartblades 2 a full-scale 20 m rotor blade for the NREL CART3 wind turbine was designed, built and tested. The rotor blade was intended to have a strong bending–torsion coupling. By means of the experiments, the proof for the technology in question was supposed to be provided. The experimental work was accompanied by simulations. The aim of the paper was to describe and publish a reference finite element model for the 20 m rotor blade. The validation procedure is presented, as are the modelling strategy and the limitations of the model. The finite element model is created using quadratic finite shell elements and quadratic solid elements. Different data sets were used for the validation. First, the data of static test bench experiments were used. The validation comprised the comparison of global displacement and local strain measurements for various flap and edge bending tests and for torsion unit loading tests. Second, the blades’ eigenfrequencies and eigenvectors in clamped and free–free scenarios were used for validation. Third, the mass distributions of the finite element and real blade were investigated. The paper provides the evaluated experimental data, and all analysed scenarios and the corresponding finite element models in Abaqus, Ansys and Nastran and formats as a reference dataset.

Tensile Properties of Natural and Synthetic Rattan Strips Used as Furniture Woven Materials

This study investigated factors on tensile properties of rattan strips commonly used as woven materials for furniture. The factors were rattan type (bast, core, synthetic), gauge length (100, 140 mm), and unit loading speed (0.1, 0.2, 0.3, 0.4, 0.5 mm/min/mm). Experimental results indicated that natural bast and core rattan strips, when subjected to tensile loading, behaved like synthetic rattan strips in terms of their stress-strain curves showing excessive plastic deformation. There was no significant difference in ultimate tensile strain between bast and synthetic rattan strips. Bast rattan strips had the highest ultimate tensile strength and modulus of elasticity among three materials evaluated in this study, followed by core rattan and synthetic strips. The major tensile properties of natural rattan bast strips can be influenced by their gauge length adapted to their evaluation test. Unit loading speeds, in general, had no significant effects on the major tensile properties of natural bast rattan strips but tended to significantly effect the ultimate strength of synthetic rattan strips, while less significantly for strengths at the proportional limit and yield point.

Tribological properties and metallurgical characteristics of different diffusion layers formed on steel

The article presents results of investigations of wear resistance by friction, employing the “3 cylinder-cone” method, of selected structural and tool steels, subjected to given thermo-chemical treatment, i.e. boriding, carburizing, nitriding, chromizing and titanizing. It was observed that a proportionality exists between their wear resistance and the value of surface unit loading. Moreover, the friction-wear properties of these layers exhibited certain differences, dependent on their microstructure and chemistry.

Central-radial bi-porous nanocatalysts with accessible high unit loading and robust magnetic recyclability for 4-nitrophenol reduction

Multifunctional bi-porous nanocatalysts derived from dendritic templates were synthesized and applied for efficient, stable and recyclable heterogeneous catalysis.

WEAR RESISTANCE CHARACTERISTICS OF THERMO-CHEMICALLY TREATED STRUCTURAL STEELS

The article presents results of investigations of wear resistance by friction, employing the “3 cylinder – cone” method, of selected structural steels subjected to given thermo-chemical treatment, i.e. nitriding, carburizing, and precipitation hardening after nitriding. The investigated steels were C45, 21NiCrMo2, 18HGT, and 41Cr4. These materials, after thermo-chemical treatment undergo metallurgical characteristics of diffusion layers formed on steel. It was observed that proportionality exists between their wear resistance and the value of surface unit loading. Moreover, the friction – wear properties of these layers exhibited certain differences, depending on their microstructure and chemistry.

DIFFUSION LAYERS FORMED ON STEEL AND THEIR WEAR BEHAVIOUR

The article presents the results of investigations of wear resistance by friction, employing the “3 cylinder-cone” method, of selected structural and tool steels, subjected to given thermo-chemical treatment, i.e. boriding, carburizing, nitriding and chromizing. It was observed that a proportionality exists between their wear resistance and the value of surface unit loading. Moreover, the friction-wear properties of these layers exhibited certain differences, dependent on their microstructure and chemistry.

The Electric-Hydraulic Servo Equipment for the Real Force and Motion Simulation of Pumping Unit

In this paper, new type electro-hydraulic servo equipment is given for testing the working feature on pumping unit. It is the key to get the real simulation of motion and loading of pumping unit. The equipment in paper can be used to repeat all kind of the real force and motion on pumping unit. In order to get better simulation results, the algorithm for self-adaptation control with Kalman filter, which is used for error-free estimate of motion state in order to obtain high accuracy, is applied to solve powerful motion error—surplus force in passive loading system . All algorithms can be used in computer. Last, the test results of pumping unit loading are given. By actual use，the results show that self-adaptation control model with Kalman filter are used for decreasing error by motion of loading system is feasible and the control model can automatically regulate coefficients of regulator.

Simulation of Postwelding Distortion Control of Stiffened Hull Blocks by Line Heating

The objective of this study is to develop an analysis method to predict the reduction of welding distortion of stiffened plates by line heating. The equivalent loading method, based on the inherent strain theory, was established to analyze the heat straightening of stiffened plates. The heat input for the analysis was obtained based on experimental temperature variation curves. Temperature distributions during two- line heating process were calculated by two-dimensional heat transfer analysis using the finite element method. The degree of restraints was estimated by combining the experimental data of simple specimen and unit loading analysis. Equivalent loads were obtained by integrating the inherent strains, which were determined from the highest temperature and the degree of restraint. Finally, the equivalent loads obtained were imposed, as applied loads, on the elastic analysis to predict the reduction of welding deformation in stiffened plates. If the basic experiments for several simple cases are carried out, the proposed method can be extended to the analysis of heat straightening of welding distortion of more complicated stiffened plates and ship hull blocks.