Papers by Keyword: Camber

Abstract: A multiphase numerical study has been carried out to understand the effects of wind turbine blade profile (airfoil) symmetry on resultant ice accretion. Two symmetric (NACA 0006 & 0012) and two non-symmetric airfoils (NACA 23012 & N-22) were used for this preliminary study. Based upon the airflow field calculations and super cooled water droplets collision efficiency, the rate and shape of accreted ice was simulated for rime ice conditions. Analysis showed higher air velocity along top surface of the non-symmetric airfoils as compared to symmetrical airfoils that also effects the droplet behavior and resultant ice growth. Results show that change in blade profile symmetry effects the resultant ice accretion. For symmetric airfoils, more streamlines ice shapes were observed along leading edge as compared to non- symmetric airfoils.

Abstract: The paper analyzes the effect of airfoil thickness, camber and blade pitch angle on the performance of the three-bladed Darrieus wind turbines. The research results show that the increase of airfoil thickness, camber and pitch angle of blade, can improve power coefficient when the wind turbine tip speed ratio between zero and four. The increase of thickness and camber of the airfoil leads to running tip speed ratio range of wind turbine get narrowed, and reduces the power coefficient when wind turbine runs in high tip speed ratio range. When the pitch angle of blade is 1˚, power coefficient reaches the maximum value. Negative pitch angle has a bad impact on power coefficient and even creates negative power coefficients.

Abstract: In the hot rolling process, the steel slab may experience a temperature gradient along its transverse direction which may cause camber and wedge after rolling. Camber and wedge phenomenon will affect the quality of the steel plate. To eliminate camber and wedge phenomenon, a pair of side guides is placed before and behind the hot rolling mill. The position mode and the force mode are the control modes for side guides to correct the slab shape and to guide the slab to follow rolling direction. Finite element analysis using ABAQUS was applied to simulate hot rolling process to find the correction mechanism of rolling equipment. The centerline of slab was traced and the shape of slab was predicted. The difference of rolling load between work side and drive side of roller was determined. Furthermore, the load, stress and velocity distribution on the slab at roll bite were analyzed. By using numerical model, hot rolling parameters including side guide control strategy can be predicted, which can provide the hot rolling line as a guideline to improve the quality of the steel slab.

Abstract: The carbody structure of electric multiple unit (here in after EMU) shall be designed withstand the loading conditions without permanent deformation or any form of damage. And the carbody shall have a minimum design life of 25 years or more in Korea. Loading conditions have a longitudinal compressive force and a vertical load. Camber of the carbody is defined as its curved shape viewed in side elevation. Carbody camber shall be a smooth arc from end to end of the carbody and shall be measured from a datum line drawn between the intersections of the arc with the center lines of the carbody bolsters to a line tangent to the arc midway between bolsters. The carbody shall be built with positive camber such that camber shall remain positive with the carbody at maximum load and shall not bind due to deflection caused by variations of service load. To assess the strength and stiffness of the designed carbody, carbodys designer shall be demonstrated by a programme of finite element analysis and testing shall be carried out in accordance with Korean standard technical specifications. The carbody is manufactured by giving the slope of the deflection to be compensated strength and stiffness. The deflection is camber. So this study analyzes that how camber affects safety and durability of carbody according to the load conditions and revenue service on main-line. Methods and analytical model of carbody structure is introduced to demonstrate them.

Abstract: Focused on the problems of prefabricated prestressed concrete small box beams cambering at mid-span, FEM theory and orthogonal test method are applied to analyze the sensitivity of factors involving elastic modulus of concrete (E), effective prestressed force (P), environmental relative humidity (RH), beam-preserving time (T) etc, and approximate expressions for calculating camber of the prestressed concrete small box beam are obtained by stepwise regression method. The fitting precision can meet the requirements of the engineering design, and the study method can provide reference for prediction and control of main beam camber.

Abstract: The plate camber is one of the thorny problems in the plate rolling process. The characteristic variables of plate camber at the delivery and at the entry sides of the mill were illustrated based on the primary concepts of camber. The relationship between the plate characteristic variable and velocity distribution in the deformation area of the plate was also determined. This paper focuses on the features of asymmetry in the transverse direction during rolling, an elastic deformation mathematical model of four-high mill has been developed to optimize the predictive model of plate camber, which ensures the theory of influence factors of plate camber to be applied in plate rolling.

Abstract: Construction monitoring is a system, especially for long-span pre-stressed concrete continuous rigid frame bridge. Based on the construction control of the right bridge Ju-ma River NO.3 Bridge, this paper has made comprehensive conclusion and detailed discussion in the aspects of construction control method, the basic process of construction control, and bridge construction control survey methods. The findings described herein will provide considerable reference for the construction control of other similar long-span bridges.

Abstract: In the manufacturing of slider, the final step is a dicing process of the rowbars into individual slider. However, in all slider separation processes seem to affect the curvature of the slider air bearing surface (ABS). As a result, the change in ABS crown and camber which can significantly affect the fly height of the slider. This paper investigates the influence of three types of dicing process, with the same feed rate and cutting speed, on the ABS curvature.

Abstract: Present modeling algorithm for large-sized revolving parts’ camber can not ensure the smoothness, so a new modeling algorithm based on NURBS Curve was proposed in this study. In detail, the new modeling algorithm is as following: Firstly transfer these discrete points, which are measured along the part’s axial lead by equal distant, into a weighting unity sequence. Secondly filter this sequence by wavelet de-noising algorithm. Thirdly replace the discrete points’ amplitudes by the corresponding weights of filtered sequence, thus yield a group of new discrete points. Lastly calculate the control vertexes and weighting factors by local rational interpolation algorithm, and construct a spatial NURBS Curve through the new discrete points to obtain the model of large-sized revolving parts’ camber. It was experimentally confirmed that this model can represent drilling stem’s camber smoothly and improve its pressure straightening precision.