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TABLE OF CONTENTS Table of Contents PARAMETRIC STUDY OF SANDWICH PANEL BUCKLING IN COMPOSITE WIND TURBINE BLADES Shicong Miao, Steven Donaldson, Elias Toubia……………………………………………………………………….….……3 A STUDY OF SIMPLIFIED SHALLOW WATER WAVES: ASSESSMENT OF ADOMIAN’S DECOMPOSITION METHOD FOR THE ANALYTICAL SOLUTION Mehdi Safari……………………………………………………………………………………….……………………..….…….16 ON BICRITERIA LARGE SCALE TRANSSHIPMENT PROBLEMS Dr. Jasem M.S. Alrajhi, Dr. Hilal A. Abdelwali, Dr. Mohsen S. Alardhi, Eng. Rafik El Shiaty…….…………..…..….21 TRIBOLOGY OF HIGH SPEED MOVING MECHANICAL SYSTEMS FOR SPACECRAFTS - TRIBOLOGICAL ISSUES K. Sathyan……………………………………………………………………………………………………..…………..……....27 THE USE OF IRON IN PEAT WATER FOR FENTON PROCESS Mirna Apriani, Ali Masduqi……………………………………………………………………………………..……….……..35 TRIBOLOGY OF HIGH-SPEED MOVING MECHANICAL SYSTEMS FOR SPACECRAFTS: LUBRICATION SYSTEMS OF BALL BEARINGS K. Sathyan………………………………………………………………………………………………………………………..39 AcademyPublish.org – Journal of Engineering and Technology Vol.2, No.2 2
PARAMETRIC STUDY OF SANDWICH PANEL BUCKLING IN COMPOSITE WIND TURBINE BLADES Shicong Miao, Steven Donaldson, and Elias Toubia Parametric Study of Sandwich Panel Buckling in Composite Wind Turbine Blades Shicong Miao, Steven Donaldson * , and Elias Toubia *Corresponding author: steven.donaldson@notes.udayton.edu Department of Civil and Environmental Engineering, University of Dayton, Dayton, OH 45469. USA ABSTRACT: A parametric study of the buckling performance of composite wind turbine blade regions with thin symmetric laminated sandwich rectangular panels, subjected to uniform axial shell edge compression loads is presented. The research focused on the critical buckling load and strain levels with core material parameters, such as transverse core shear modulus and core thickness, for rectangular sandwich strips with long aspect ratios. Both flat and curved-section models were considered. The buckling design plots generated provide an insight into optimal core solutions for efficient designs. NOMENCLATURE a = length of the panel, m b = width of the panel, m c = core thickness, m k = panel curvature ratio, % (arc height divided by the panel width) l = curve length, m r = radius, m t = facing thickness on one surface, m h = overall thickness of sandwich C 0 = normalized core thickness (core thickness divided by total facing sheet thickness) 1, 2, 3 = general coordinates. (1:longitudinal direction; 2: width direction; 3: direction normal to the panel planform) r, t, z = cylindrical coordinates. (r: radial direction normal to panel; t: curve angle direction; z: longitudinal direction) U 1, U 2 , U 3 = displacement in 1, 2, 3 direction U r, U z , U t = displacement in r, z, t direction P cr = critical buckling end load (=eigenvalue), N/m ε cr = critical buckling end strain, % E 1 , E 2 , E 3 = Moduli of elasticity G 13 = Core transverse shear modulus in 1-3 plane, Pa G 23 = Core transverse shear modulus in 2-3 plane, Pa ν 12 , ν 21, ν 23 = Poisson's ratios N 1 = Uniform compressive end load, N/m INTRODUCTION Renewable energy sources continue to increase as a percentage of global energy production. This trend is dominated by wind energy and is the result of both an increase in the number of turbines installed, as well as the increasing diameter of turbine rotors with the corresponding energy output per turbine (Roczek, 2010). As a consequence of this design strategy, the blade structures are becoming increasingly thinwalled, such that buckling problems in the blade panels must be addressed (Lund, Johansen, 2008). In general, the wind turbine blade works in much the same way as the steel I-beam, except that there are shells around the outside that form the aerodynamic shape and resist buckling and torsional loads (WE Handbook- 3- Structural Design). Utility-scale wind turbine blades use extensive sandwich construction, in both the aerodynamic shells and shear webs. To meet stiffness constraints such as deflection limits, the fiber composite materials in the broad unsupported spans of shell and shear web laminates are stiffened through the use of sandwich construction to prevent local deformation and buckling. In blade structures, the largest single role of the sandwich core is to assure adequate stability of the large panel regions against buckling. As such, the most significant attributes of the core materials are the transverse shear modulus and the core thickness. Since core materials are generally available in a wide range of weights, mechanical properties, and cost, a study focused on the shell core is appropriate. Several related and valuable plate buckling studies and wind turbine blade preliminary design studied have been done in this area. General wind turbine blade optimization methods are discussed and presented in (Roczek, 2010, Lund, Johansen, 2008 and Lund, 2005). Structural reliability and mechanical behavior predictions for blade materials are reported in reference (Mishnaevsky et al., 2011). A preliminary design study of an advanced 50 m blade for utility wind turbines is presented in reference (Jackson et al., 2005) Closed form, exact solutions for the buckling of simply supported, rectangular, orthotropic plates under different load conditions are given in (Narita, Leissa, 1990, Leissa, 1985). Many nondimensional buckling parameters were generated by Nemeth and Weaver ( Nemeth, 1995, Nemeth 2004, Weaver, Nemeth, 2007) for long or infinitely long symmetrically laminated anisotropic rectangular plates subjected to various combined load conditions. Theoretical prediction of buckling loads for cyclic sandwich shells under axial compression with laminated facings and foam core is presented in (Morovvati, 2011). Although many researchers have investigated the buckling of simply supported laminated composite plates, the early buckling analysis works focused on anisotropic plate AcademyPublish.org – Journal of Engineering and Technology Vol.2, No.2 3
Page 1: AcademyPublish.org Volume 2 Issue 2
Page 5 and 6: PARAMETRIC STUDY OF SANDWICH PANEL
Page 17 and 18: A STUDY OF SIMPLIFIED SHALLOW WATER
Page 19 and 20: A STUDY OF SIMPLIFIED SHALLOW WATER
Page 21 and 22: ON BICRITERIA LARGE SCALE TRANSSHIP
Page 27 and 28: TRIBOLOGY OF HIGH SPEED MOVING MECH
Page 35 and 36: THE USE OF IRON IN PEAT WATER FOR F
Page 37 and 38: THE USE OF IRON IN PEAT WATER FOR F
Page 39 and 40: TRIBOLOGY OF HIGH-SPEED MOVING MECH
Page 45: Other access free resources from Ac

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