Motion-based design approach for a novel variable friction cladding connection used in wind hazard mitigation

Abstract

Cladding systems typically serve architectural purposes and protect occupants against the external environment. It is possible to leverage these systems to enhance structural resiliency. A common application is the use of blast resistant panels for enhanced protection against man-made hazards, whereas energy is dissipated through sacrificial elements. However, because these protection systems are passive, their mitigation capabilities are bandwidth limited, therefore targeting single types of hazards. The authors have recently proposed a novel variable friction cladding connection (VFCC), which enables the leveraging of cladding inertia for mitigating blast, wind, and seismic hazards. The variation in the friction force is generated by an actuator applying pressure onto sliding friction plates via a toggle system. Previous work has characterized the dynamic behavior of a VFCC prototype, and established design procedures for blast mitigation applications. Here, work is extended for applications to wind mitigation. An analytical model is developed to characterize the dynamic behavior of the VFCC for wind-induced vibrations. A motion-based design framework is developed to enable an holistic integration of the device within the structural design phase. Numerical simulations are conducted on a 24-story building example to demonstrate the motion-based design methodology. Results show that the semi-active cladding system provides significant reduction in the wind-induced inter-story drift and floor acceleration, therefore demonstrating the promise of the VFCC for field applications.

Variable friction cladding connection for seismic mitigation

“…Variable friction has been widely studied in structural control with devices leveraging electromechanical- [49,50], electromagnetic- [51,52], magnetorheological- [53,54], hydraulic- [41,55], and piezoelectric- [56,57] based actuation. Prior work on the VFCC consisted of prototyping and characterizing the device [58], and developing an MBD methodology for blast [59] and wind [60] mitigation.…”

“…represented by a harmonic excitationẍ g (t) = ẍ g e jΩt , where ẍ g is the amplitude of excitation. Following the standard derivation for the steady state response of the reduced structure-cladding system [1,60], the amplitudes of the responses are written…”

“…with g n (λ) = b 0 λ 2n−2 + b 1 λ 2n−4 + ... + b n−1 (58) and h n (x) = a 0 λ n + a 1 λ n−1 + ... + a n (59) its analytical solution follows [79] J = jπQ n a 0 V n (60) where j is the imaginary unit, and V n and Q n are the determinants of the following matrices 61, the analytical solution for J ci can be expressed in terms of the determinants of matrices V n and Q n using Eq. 60.…”

Vibration Damping Performances of Buildings with Moving Façades Under Harmonic Excitation

“…On the other hand, concerning MF systems, it is desirable to endow the connection with enhanced dissipative features. Various types of devices can be conceived for this purpose and the use of high-damping or smart materials, like, for example, friction-based or Shape Memory Alloys might contribute to improve the performances of the MF systems [12,15,17].…”

“…In the context of buildings with DSF, Moon [8] proposed to exploit relative displacement between the façade and the main structure to improve the dynamical behavior of tall buildings subject to wind actions. This idea has then been further explored in [9][10][11][12]. In this concept, the mass of the façade is used to reduce vibrations of the main structure in a way conceptually similar to tuned mass dampers (TMD) but without the need to endow the building with additional mass and with the advantage of saving useful space for the allocation of vibration damping devices.…”