Title of Dissertation: SMART FOAM FOR ACTIVE VIBRATION AND NOISE CONTROL Wael Nabil Akl, Doctor of Philosophy, 2004 Dissertation Directed By: Professor Amr M. Baz Department Mechanical Engineering A new class of smart foams is introduced to simultaneously control the vibration and noise radiation from flexible plates coupled with acoustic cavities. The proposed smart foam consists of a passive ...

Cube-shaped PZT single crystals with PZ/PT=55/45 composition were grown in a relatively uniform size distribution around 80μm by a PbO-flux method. The PZT grains obtained were mixed with liquid polyimide resin and rolled on a glass plate to fabricate 1-3-type composite sheet. This rolling process resulted in a high orientation of the PZT grains as the {h00} are parallel to the substrate plane....

n,n-dichloropolystyrene sulfonamide as a decontaminant was synthesized in 5 steps from styrene monomer. styrene was first polymerized. then, sulfonation reaction was performed by h2so4 (c) followed by chlorination with pocl3 obtain chlorosulfonated polystyrene. amidification reaction was then applied to get sulfonamide resin. sulfonamide resin was treated with sodium hypochloride to obtain n,n-...

There are many objects for which the attenuation varies significantly as they are rotated during computerized X-ray tomography, for example plate samples. This can lead to significant ring artefacts in the subsequent tomographic reconstructions. In this paper a new method is presented that can successfully suppress such ring artefacts and is applicable to both parallel and cone-beam geometries....

In this work, a model based on the combination of two approaches XFEM and CZM, has been used to predict damage repairs by composite patch (patch/adhesive/plate assembly). This degradation is analyzed in terms adhesive considering both initiation propagation interfacial debonding. The cohesive zone patch/adhesive/plate system defined its properties resistance debonding estimated from displacemen...

fiber metal laminates (fmls) are new composite materials consisting of thin metal layers and high strength composite layers. arall (aramid aluminum laminate) is a family of the fml that consists of thin aluminum sheets along with kevlar/epoxy composite layers. this material has many advantages such as light weight, excellent corrosion, fatigue and impact resistance. since, arall is a new materi...

A vibration based damage identification algorithm is implemented to assess the damage of a thin–walled composite structure. The structure analysed is a skin with stiffeners, as frequently applied in aircraft components. Both experimental and numerical studies on a single composite skin–stiffener structure showed that the modal strain energy damage index (MSE–DI) algorithm is a suitable method f...

This study presents an analytical investigation into the mechanical behavior of a cartilage-polydioxanone (PDS) plate composite grafts. Numerical methods are used to provide a first-order, numerical model of the flexural stiffness of a cartilage-PDS graft. Flexural stiffness is a measure of resistance to bending and is inversely related to the amount of deformation a structure may experience wh...

BACKGROUND Most military helmets are designed to prevent penetration by small firearms using composite materials in their construction. However, the transient deformation of the composite helmet during a non penetrating impact may result in severe head injury. METHOD Two experimental designs were undertaken to characterize the extend of injuries imparted by composite panels using in protectiv...

Guided waves based methods are widely used for damage detection and localization in metallic and composite structures. Success of the method application depends on many factors like sensors/actuators location, sensor electronic system design, sensor shape, frequency range of excitation waves and applied signal processing procedures. Authors developed new modified LISA and EFIT algorithms to sol...