> >Aswind energy is aggressively expanding within the alternative sources’ part ofmodern world’s energy pie, the need of addressing various obstacles that limitfurther wind utilization becomes all the more urgent. From a structuralengineering point of view, surmounting the tower-base diameter limitation,dictated by the current transportation capabilities, is one of the industry’sprimary issues. The concept presented in this study, as a means to address thisissue, is the implementation of a composite, sandwich-type tower section insteadof today’s predominant, conventional steel-only tubular section. The proposedsection consists of two steel faces and a core of some lightweight material,binding and keeping them at a specified distance, thus providing significantlyimproved mechanical properties with minimal additional weight and cost. As aninitial step towards a feasibility investigation of the proposed section, theanalytical expressions that govern its behavior under either axial or bendingloads are formulated in the current study. The results are verified by comparisonwith those obtained from a specialized composite section software, as well as ageneral purpose finite element software. The analytical solution is thenemployed to carry out extensive parametric analyses, involving a wide range ofmaterial qualities and layer thicknesses, leading to the optimization of thesection, in terms of either elastic bending strength or initial stiffness.Finally, the determination of the optimal section-properties, which provide themost efficient solution regarding both criteria, is addressed, resulting in apreliminary design tool for sandwich-type, wind-turbine-tower sections.
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