Based on known theoretical developments in linear dynamics of homogeneous beams, two homogenization approaches of composite beams are developed further to an anterior work using two equivalent properties: the physical and the mechanic–geometrical properties. Further to the assumption of Euler–Bernoulli beams, dynamic parameters are needed. Equations of a given beam structure subjected to free un-damped and/or damped vibration are established. The natural frequency responses of the first five modes are obtained from both approaches, and then compared with those obtained from a finite element model approach, taking into account different slenderness and boundary conditions. The result shows good agreement. An extension to the equivalent physical parameter homogenization method using the behaviour law in nonlinear state is presented here. Thus, the homogenization is extended to an elastically equivalent model elaboration for a system having an elastic–plastic and bilinear behaviour. The aim is to use analytical expressions from an elastically equivalent model for a nonlinear system of multilayer beam type to obtain the new corrected dynamic parameter. Based on the ductility factor method combined with the secant method that uses a substitute structure and secant stiffness to account for nonlinear behaviour, we developed a formula using global
effective Es∗, the equvalent mass density ρ∗, as well as the two types of viscous damping parameter (these types include a viscous resistance to transverse
displacement C∗ of the beam anda viscous resistance to straining of the beam material CS∗) which can be
incorporated into the formula without difficulty. The
nonlinear analysis shows that the degradation of
rigidity decreases the frequencies response curve,
which tends to increase the vibration periods giving an additional storage space for the structure capacity to accumulate displacements of a higher degree
compared to those of the elastic case. The
importance of the nonlinearity assumption is shown,
Yettou F, Azoui B, Malek A, Gama A, Panwar NL. Solar cooker realizations in actual use: An overview. Renewable and Sustainable Energy Reviews, SeptemberRenewable and Sustainable Energy Reviews, September. 2014;37 :288–306.
Bouzeria H, Fetha C, Bahi T, Lekhchine S, Rachedi L. Speed Control of Photovoltaic Pumping System. International Journal of Renewable Energy Research (IJRER)International Journal of Renewable Energy Research (IJRER). 2014;4 :705-713.
Intermittently connected mobile networks are wireless networks, where, often, there is no complete path between the source and destination nodes and, the network is considered as a set of disconnected groups. This definition is related to Delay Tolerant Networks (DTN). Thus, several studies have been performed to design routing protocols that consider substantially delay tolerance constraint. In this paper, we investigate the projection of spray and wait routing protocol, which is dedicated to DTNs environments, in Wireless Sensor Networks (WSNs). The obtained results from the intensive performance evaluation of our proposal prove obviously the efficiency of spray and wait protocol in WSNs.
