Developing a Smart Façade System Controller for Wind-Induced Vibration Mitigation in Tall Buildings

Abstract

Tall and slender buildings often endure disturbances resulting from winds composed of various mean and fluctuating velocities. These disturbances result in discomfort for the occupants as well as accelerated fatigue life cycles and premature fatigue failures in the building. This work presents the development of a smart morphing façade (Smorphaçade) system that dynamically alters a buildings’ external shape or texture to minimize the effect of wind-induced vibrations on the building. The Smorphacade system is represented in this work by a series of plates that vary their orientation by means of a central controller module. To validate the simulation, a simple NACA0012 airfoil is simulated in a stream of air at a Reynolds number (RE) of 2 million. The pressure and viscous force profiles are captured to plot the variation of the lift force for different angles of attack that are then validated using published experimental airfoil data. After validation, the airfoil is attached to a linear spring-damper combination and is allowed to translate vertically without rotation according to the force profile captured from the surrounding air stream. A PID controller is developed to equilibrate the vertical position of the airfoil by altering its angle of attack. The model and its utility functions are implemented as an OpenFOAM® module (MSLSolid). Thereafter, the model is expanded to handle a planar case of a building floor carrying 4 controllable plates. The forces on the building profile are summed at the centroid of the building and the windward rigid body motion of the floor is estimated by reflecting the horizontal force component on a Finite Element (FE) model of the building. The time series information of the force acting on the building and the resulting oscillations are captured for exhaustive combinations of the plate angles. This data is used to build a lookup table that gives the best plate configuration for a given wind condition. A controller operates in real-time by searching the lookup table using readings of the wind condition. Preliminary results show a 94% reduction in the amplitudes of wind-induced vibrations.