Dynamical analysis of wind turbine blades based on harmonic response

As the forces applied on the wind turbine blade are irregular, the deformation and concentrated stress of the blade may vary with the load and excitation. And the lamination of composite materials is critical to blade design, it directly affects the performance and power of wind power plants. In this paper, the response characteristics of the wind turbine blade is analyzed by the application of the harmonic response method under different ply angles. Through the simulation results, the performance of the actual blade is estimated, and the rationality of this design is judged. The results demonstrate that the blade displacement response amplitude is the minimum when ply angle is 45°. It is also found that the maximum displacement response occurs in the Y direction (i.e. parallel to the flow direction) by analyzing the displacement of each section in the blade, while the maximum stress is located at blade root

A new column-generation-based algorithm for VMAT treatment plan optimization

We study the treatment plan optimization problem for volumetric modulated arc therapy (VMAT). We propose a new column-generation-based algorithm that takes into account bounds on the gantry speed and dose rate, as well as an upper bound on the rate of change of the gantry speed, in addition to MLC constraints. The algorithm iteratively adds one aperture at each control point along the treatment arc. In each iteration, a restricted problem optimizing intensities at previously selected apertures is solved, and its solution is used to formulate a pricing problem, which selects an aperture at another control point that is compatible with previously selected apertures and leads to the largest rate of improvement in the objective function value of the restricted problem. Once a complete set of apertures is obtained, their intensities are optimized and the gantry speeds and dose rates are adjusted to minimize treatment time while satisfying all machine restrictions. Comparisons of treatment plans obtained by our algorithm to idealized IMRT plans of 177 beams on five clinical prostate cancer cases demonstrate high quality with respect to clinical dose–volume criteria. For all cases, our algorithm yields treatment plans that can be delivered in around 2 min. Implementation on a graphic processing unit enables us to finish the optimization of a VMAT plan in 25–55 s.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98593/1/0031-9155_57_14_4569.pd