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The problem of mechanical design, performance prediction (e.g., flap-wise/edge-wise bending stiffness, fatigue-controlled life, the extent of bending-to-torsion coupling), and material selection for a prototypical 1 MW horizontal-axis wind turbine (HAWT) blade is investigated using various computer-aided engineering tools. For example, a computer program was developed which can automatically generate both a geometrical model and a full finite-element input deck for a given single HAWT-blade with a given airfoil shape, size, and the type and position of the interior load-bearing longitudinal beam/shear-webs. In addition, composite-material laminate lay-up can be specified and varied in order to obtain a best combination of the blade aerodynamic efficiency and longevity. A simple procedure for HAWT-blade material selection is also developed which attempts to identify the optimal material candidates for a given set of functional requirements, longevity and low weight.

A multi-disciplinary design-optimization procedure has been introduced and used for the development of cost-effective glass-fiber reinforced epoxy-matrix composite 5 MW horizontal-axis wind-turbine (HAWT) blades. The turbine-blade cost-effectiveness has been defined using the cost of energy (CoE), i.e., a ratio of the three-blade HAWT rotor development/fabrication cost and the associated annual energy production. To assess the annual energy production as a function of the blade design and operating conditions, an aerodynamics-based computational analysis had to be employed. As far as the turbine blade cost is concerned, it is assessed for a given aerodynamic design by separately computing the blade mass and the associated blade-mass/size-dependent production cost. For each aerodynamic design analyzed, a structural finite element-based and a post-processing life-cycle assessment analyses were employed in order to determine a minimal blade mass which ensures that the functional requirements pertaining to the quasi-static strength of the blade, fatigue-controlled blade durability and blade stiffness are satisfied. To determine the turbineblade production cost (for the currently prevailing fabrication process, the wet lay-up) available data regarding the industry manufacturing experience were combined with the attendant blade mass, surface area, and the duration of the assumed production run. The work clearly revealed the challenges associated with simultaneously satisfying the strength, durability and stiffness requirements while maintaining a high level of wind-energy capture efficiency and a lower production cost.

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In order to help meet the needs of automotive original equipment manufacturers and their suppliers for a cost-effective, robust, reliable polymer-metal-hybrid (PMH) technology which can be used for the manufacturing of load-bearing body-in-white (BIW) components and which is compatible with the current BIW manufacturing process chain, a new approach, the so-called direct-adhesion PMH technology, was recently proposed (Grujicic et al., J. Mater. Process. Technol., 2008, 195, p 282-298). Within this approach, the necessary level of polymer-to-metal mechanical interconnectivity is attained through direct adhesion and mechanical interlocking. In the present work, a new concept for mechanical interlocking between the metal and plastics is proposed and analyzed computationally. The approach utilizes some of the ideas used in the spot-clinching joining process and is appropriately named clinch-lock PMH technology. To assess the potential of the clinch-lock approach for providing the required level of metal/polymer mechanical interlocking, a set of finite-element based sheet-metal forming, injection molding and structural mechanics analyses was carried out. The results obtained show that stiffness and buckling resistance levels can be attained which are comparable with those observed in the competing injection overmolding PMH process but with an $3% lower weight (of the polymer subcomponent) and without the need for holes and for overmolding of the free edges of the metal stamping.