Technology Record - Issue 24: Spring 2022

120 www. t e c h n o l o g y r e c o r d . c om Founded in 2003, Liftra is recognised by the international wind turbine industry as a professional specialist in lifting and transportation solutions. Liftra has undergone rapid growth as a contributor and trusted partner, with locations in Denmark, the USA, Spain, China and Poland. Liftra has revolutionised the installation of wind turbines by creating the LT1500 crane that ‘climbs’ the wind turbine tower as it is being assembled instead of sitting beside it. The bottom of the crane grabs onto a flange of one tower section and lifts the next section into place. Then, a hoist block travels up and attaches to the higher section and pulls the crane up the tower to attach to the higher flange. In a sequence of such grabbing and hoisting moves, an entire wind turbine, including the tower, nacelle, rotor, and blades, can be constructed. With 50 engineers working primarily in Spain and Denmark, Liftra is developing this crane for use by the original equipment manufacturers of wind turbines and maintenance staff wind farms. In designing the smaller climbing crane that would take up less ground space and require just one truck to move to the next installation site, Liftra engineers needed to be able to ensure that the tower elements would not be crushed by the applied climbing forces, including the load on the tower and flanges, and the gripping forces. They therefore ran finite element structural simulations both in Ansys Cloud and on their own workstations to model the loads involved when a crane is attached to and climbs up the long tower of a wind turbine as it is being assembled. They ran both linear material models and non-linear material models for elastic or plastic analysis of the towers to determine whether the crane would cause any permanent deformation to the tower, and, if so, how much. Liftra used the Ansys Cloud to simulate the design of a revolutionary new ‘climbing’ crane for constructing wind turbines up to five times faster Simulation at speed P ROF I L ED : L I F T RA