Smart beams

Classical and soft robust active control of smart beams... 

ABSTRACT Smart structures usually incorporate some control schemes that allow them to react against disturbances. In mechanics we have in mind suppression of mechanical vibrations with possible applications on noise and vibration isolation. A model problem of a smart beam with embedded piezoelectric sensors and actuators is used in this paper. Vibration suppression is realized by using active control. Classical mathematical control usually gives good results for linear feedback laws under given assumptions. The design of nonlinear controllers based on fuzzy inference rules is proposed and tested in this chapter. 

In the smart beam of Figure 1, the control actuators and the sensors are piezoelectric patches symmetrically bonded on the top and the bottom surfaces of the host beam. Both piezoelectric layers are positioned with identical poling directions and can be used as sensors or actuators. 

The main objective is to design robust control laws for the smart beam bonded with piezoelectric S/A subjected to external induced vibrations. For this purpose the following state space representation will be used ... 

Marinova, D.G., Stavroulakis, G.E. Zacharenakis, E.C. 2005. Robust control of smart beams in the presence of damage-induced structural uncertainties. International Conference PhysCon 2005 Saint Petersburg, Russia. 

Stavroulakis, G.E., Eoutsitzi, G., Hadjigeorgiou, V., Marinova, D.G. Baniotopoulos, C.C. 2005. Design and Robust Optimal Control of Smart Beams with Application on Vibrations Suppression, Advances in Engineering Software, 36, 806-813. 

Analytical solutions of the governing equations with coupled shear and peel stresses were discussed in detail in Luo and Tong (2002) for piezoelectric smart beams, in which the Euler beam theory was used. Stress analysis for adhesively bonded composite joints is to solve Eq. 24.45 with boundary conditions in Eq. 24.49. 

Lee J, Kim H (2007) Elasto-plastic analysis of adhesively bonded symmetric single lap joints under in-plane tension and edge moments. J Adhes 83(9) 837-870 Liljedahl CDM, Crocombe AD, hab I4A, Ashcroft lA (2006) Damage modelling of adhesively bonded joints. Int J Fract 141(1—2) 147—161 Luo Q, Tong L (2002) Exact static solutions to piezoelectric smart beams including peel stresses-1 theoretical formulation. Int J Solids Struct 39( 18) 4677-4695... 

However, most of these improvement methods are traditionally based on the mechanical stiffening m ods. They cannot adaptively adjust the stress distribution. In order to smartly and efficiently improve the joint strength, Cheng and his-coworkers have recently introduced a smart joint concept into the traditional adhesively bonded joint by integrating with piezoelectric materials, which have been confirmed as a very effective method to smartly reduce the stress concentration in the adhesive layer. Here, we will give an overview on the state-of-the-art of the adhesively bonded smart beam-like and tubular joints [9-13]. 

Adhesively Bonded Smart Beam-Like Joint... 

Most of the adhesively bonded pipe joints used in engineering, such as adhesively bonded socket joints, butt-weld and strap joints and heat activated coupling joints etc., can be basically regarded as two pieces of composite pipes joined by a connection coupler via the bonding adhesive, as shown in Figure 5. In order to reduce the stress concentration influence on the joint system, the smart beam-like joint concept was extended to develop a novel adhesively bonded smart composite pipe joint system by integrating the smart piezoelectric... 

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