Active Control of Tall Buildings

Duffour

Winslow

2019

Struct Multidisc Optim

114

This paper presents the formulation of a new methodology to design adaptive structures. This design method synthesises structural configurations that are optimum hybrids between a passive and an active structure. An optimisation scheme searches for an optimal material distribution and actuation layout to minimise the structure whole-life energy which consists of an embodied part in the material and an operational part for structural adaptation. Instead of using more material to cope with the effect of loads, here, strategically located active elements redirect the internal load path to homogenise the stresses and change the shape of the structure to keep deflections within required limits. To ensure the embodied energy saved this way is not used up to by actuation, the adaptive solution is designed to cope with ordinary loading events using only passive load-bearing capacity whilst relying on active control to deal with larger events that have a smaller probability of occurrence. The design methodology has been implemented for statically determinate and indeterminate reticular structures. However, the formulation is general and could be implemented to other structural types. Numerical simulations on a truss system case study confirm that substantial savings up to 50% of the whole-life energy can be achieved by the adaptive solution compared to a passive solution designed using state of the art optimisation methods.

Section: Adaptation In Structural Applicationsmentioning

confidence: 99%

Synthesis of minimum energy adaptive structures

Duffour

Winslow

2019

Struct Multidisc Optim

114

“…strong winds, earthquakes) (Soong 1988). Active brace systems have been tested using hydraulic actuators fitted as cross-bracing elements of the structure controlling directly its deflections (Abdel-Rohman and Leipholz 1983;Reinhorn et al 1992;Bani-Hani and Ghaboussi 1998). Deflection reduction in cable stayed bridges can be obtained via control forces provided by the stay cables working as active tendons (Rodellar et al 2002;Xu et al 2003).…”

Section: Adaptation In Structural Applicationsmentioning

confidence: 99%

Designing and Prototyping Adaptive Structures—An Energy-Based Approach Beyond Lightweight Design

Springer Series in Adaptive Environments

2018

This chapter presents an overview of an original methodology to design optimum adaptive structures with minimum whole-life energy. Structural adaptation is here understood as a simultaneous change of the shape and internal load-path (i.e. internal forces). The whole-life energy of the structure comprises an embodied part in the material and an operational part for structural adaptation. Instead of using more material to cope with the effect of rare but strong loading events, a strategically integrated actuation system redirects the internal load path to homogenise the stresses and to keep deflections within limits by changing the shape of the structure. This method has been used to design planar and spatial reticular structures of complex layout. Simulations show that the adaptive solution can save significant amount of the whole-life energy compared to weight-optimised passive structures. A tower supported by an exo-skeleton structural system is taken as a case study showing the potential for application of this design method to architectural buildings featuring high slenderness (e.g. long span and high-rise structures). The methodology has been successfully tested on a prototype adaptive structure whose main features are described in this chapter. Experimental tests confirmed the feasibility of the design process when applied to a real structure and that up to 70% of the whole-life energy can be saved compared to equivalent passive structures.

“…In civil engineering, active control has been mostly implemented for vibration suppression of structures under extreme loading events [1,2,3]. Different systems including active bracing for buildings and active cable-tendons for bridges through hydraulic actuators have been studied [4,5,6,7]. Shape control has been investigated to reduce the static as well as the dynamic response of tensegrity structures [8,9,10,11,12], to improve airplane maneuverability through morphing wings [13,14,15] as well as for the control of direct daylight in buildings [16].…”

Section: Introductionmentioning

confidence: 99%

Minimum energy adaptive structures – All-In-One problem formulation

Wang

2020

Computers & Structures

This paper presents a new All-In-One (AIO) implementation of an existing formulation to design adaptive structures through Total Energy Optimization (TEO). The method implemented in previous work is a nested optimization process, here named TEO-Nested. Numerical simulations and experimental testing have shown that the TEO-Nested method produces structures that embody and use significantly lower energy compared to passive designs. However, TEO-Nested does not guarantee solution optimality. The formulation presented in this paper is an AIO optimization based on Mixed Integer Nonlinear Programming (MINLP), here named TEO-MINLP. Element cross-section areas, internal forces, nodal displacements and control commands are treated as continuous variables while the actuator positions as binary variables. Stress and displacement limits are included in the optimization constraints. Case studies of reticular structures are employed to benchmark the solutions with those produced by the TEO-Nested method. Results have shown that both formulations produce similar solutions which are only marginally different in energy terms thus proving that the TEO-Nested method tends to converge to optimal (local) solutions. However, the computation time required by TEO-Nested is only a fraction of that required by TEO-MINLP which makes the former more suitable for structures of complex layout that are made of many elements.