0000000000220699
AUTHOR
Ali El-hafidi
Thermomechanical Behavior of Beams Covered with Viscoelastic Patches
International audience; Infrared thermography is a non-destructive test method based on infrared measurement that provides a luminance map of the thermal scene observed, converting to temperature. The thermographic study allows a surface observation of the thermal effects in order to display the result as a film of the temperature distribution [1]. The present study focuses on the detection of volumetric energy sources in beams covered by viscoelastic patches.
Potentiel D’utilisation D’ondes Élastiques Guidées Pour La Caractérisation De Sandwichs Et De Multicouches Composites
International audience
Characterization of the Dynamic Interaction between Chassis and Powertrain of a Vehicle Using the Coupling Matrix
International audience; This study is concerned with the vibration transmission between two subsystems of a vehicle: the chassis which is considered as an elastic structure and the powertrain which is considered as a rigid body. The study is carried out based on a new coupling matrix constructed from equations of dynamic behavior of each subsystems. This matrix depends only on the impedance matrices of the two subsystems and the mechanical characteristics of the linking mounts. Under some assumptions, a simplified expression to obtain the overall behaviour of the entire system is proposed. Despite its sensitivity to the degree of coupling between the subsystems, this method can be applied t…
IDENTIFICATION OF THE VISCOELASTIC CONSTITUTIVE EQUATIONS OF FLAX FIBREREINFORCED LAMINATESBY VIBRATION ANALYSIS
International audience; Experimental and numericalapproaches to identify the viscoelastic properties of flax fibrereinforced epoxy composite laminatesare proposed in this study. The method used consisted theidentification of the evolutions of both loss factor and stiffness through the use of the frequency responses. Several free-free symmetrically guided beams were excited on the dynamic range of 10 to 4000 Hz with a swept sine excitation focused around their first’s modes. A fractional derivative Zener model was used to predict the behaviourof on-axis ply complex moduli. The modified ply constitutive law was then implemented in Classical Lamination Theory (CLT) calculation routine. The pro…
Characterization of the dynamic behaviour of flax fibre reinforced composites using vibration measurements
International audience; Experimental and numerical methods to identify the linear viscoelastic properties of flax fibre reinforced epoxy (FFRE) composite are presented in this study. The method relies on the evolution of storage modulus and loss factor as observed through the frequency response. Free-free symmetrically guided beams were excited on the dynamic range of 10 Hz to 4 kHz with a swept sine excitation focused around their first modes. A fractional derivative Zener model has been identified to predict the complex moduli. A modified ply constitutive law has been then implemented in a classical laminates theory calculation (CLT) routine.
Dynamic Coupling Study between Substructures. Application to the Chassis-Powertrain Interaction
International audience
Optimization of Passive Constrained Layer Damping (Pcld) Treatments for Vibration Reduction
An efficient method to reduce the frequency averaged transverse vibration level of aplate by optimizing the position of attached passive constrained layer damping PCLD is presented.This method uses a multilayer anisotropic plate model which is an equivalent single layer platemodel (ESL) where transverse shear stresses and displacements are continuous at each layer’sinterfaces. Hence, for a laminate composed of an arbitrary number of layers, all the quantities arerelated to those of the first layer. The optimization process is based on the use of the ESL platemodel combined with the genetic algorithm (GA) and Latin Hypercube Sampling (LHS) algorithmimplemented in a Rayleigh-Ritz resolution p…
Determination of dynamic properties of flax fibres reinforced laminate using vibration measurements
International audience; Experimental and numerical methods to identify the linear viscoelastic properties of flax fibre reinforced polymer (FFRP) composite are presented in this study. The method relies on the evolution of storage modulus and loss factor as observed through the frequency response. Free-free symmetrically guided beams were excited in the dynamic range of 10 Hz to 4 kHz with a swept sine excitation focused around their first modes. A fractional derivative Zener model has been identified to predict the complex moduli. A modified ply constitutive law has been then implemented in a classical laminates theory calculation (CLT) routine. Overall, the Zener model fitted the experime…