in this paper a new method for nondestructive testing or nondestructive evaluation is proposed for glass-epoxy composite. for this purpose, impact-echo is used to evaluate the properties of composite materials, detecting internal defects and thickness measurement. in the impact-echo method a steel ball impacts on a composite plate and generates stress waves or p-waves which will be transferred ...

In the last decades, researchers have developed new materials to improve the quality of human life. Owing to the frequent occurrence of bone fractures, it is important to develop plate materials for the fixation of fractured bones. These plate materials have to be lightweight, compatible with human tissues and ought to allow stiffness. Natural fibers have the advantage that they are renewable r...

The steel shear wall and composite steel plate shear wall is introduced in recent three decade and is considered and is spread rapidly. Composite steel plate shear wall which is made of a layer of thin steel sheet with coating of reinforced concrete in one or both sides of steel palate is considered a third generation of resistance shear walls against lateral loads that in addition to increasin...

objective: long-term retention of pit and fissure sealants is crucial for their success. this clinical study evaluated the retention rate of a flowable composite resin (filtek supreme xt flowable restorative) compared to a conventional resin-based sealant (concise light cure white sealant) over 12 months. materials and methods: forty subjects aged 6 to 9 years were included in the study. using ...

We investigate the global bifurcations and multipulse chaotic dynamics of a simply supported laminated composite piezoelectric rectangular thin plate under combined parametric and transverse excitations. We analyze directly the nonautonomous governing equations of motion for the laminated composite piezoelectric rectangular thin plate. The results obtained here indicate that the multipulse chao...

In this work, repaired crack in 6061T6 aluminum plate with composite patches presented, firstly we determine the displacement, strain and stress, also the first six mode shape of the plate, secondly we took the same model adding central crack initiation, which is located in the center of the plate, its seize vary from 20 mm to 60 mm and we compare the first results with second. Thirdly we repai...

Short banana fiber reinforced composites have been prepared in laboratory to determine mechanical properties. It has been observed that as soon as the percentage of the banana fiber increases slightly there is a tremendous increase in ultimate tensile strength, % of strain and young modulus of elasticity. Reinforcement of banana fibers in epoxy resin increases stiffness and decreases damping pr...

This paper presents a solution to the boundary stabilization of a symmetric composite laminated plate in free transverse vibration. The symmetric composite laminated plate dynamics is presented by a linear fourth order partial differential equation (PDE). A linear control law is constructed to stabilize the plate. The control force consists of feedback of the velocity at the boundary of the pla...