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Influence of the Length of Components from Polymer Composite on Selected Machinability Indicators in the Circumferential Milling Process

Ciecieląg Krzysztof

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no 4

229--239

EN

The article presents the results of the research on the influence of the length of elements made of carbon fiber reinforced plastics (CFRP) and glass fiber reinforced plastics (GFRP) on surface roughness, surface topography, passive forces and cutting torques after circumferential milling with diamond-coated inserts (PCD). The paper also presents the results of the research on the stiffness of the elements depending on their length. The samples of composite materials were clamped in a vise at the machining center. The length of the element was defined as the unsupported distance between the milled surface and the place of attachment of the composite element. With constant milling parameters, the maximum values and amplitudes of the values of passive forces and cutting torques at variable element lengths were determined. The obtained surface was measured in order to determine the surface roughness parameters and 3D topography. The research showed that the carbon fiber reinforced plastics is on average one and a half times stiffer than that the glass fiber reinforced plastics. On the basis of the results obtained, it was found that the passive forces and cutting torques as well as the roughness parameters increase along with the length of the element. It was also shown that for the glass fiber reinforced plastics, above a certain length, the surface roughness clearly deteriorates.

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Experimental investigation on effective detection of delamination in gfrp composites using taguchi method

Ng S., Ismail N., Ali A., Sahari B., Yusof J.

Advances in Materials Science

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2012

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Vol. 12, nr 3(33)

16-24

EN

Detection of delamination defect in glass fiber reinforced plastics (GFRP) by using ultrasonic testing has been a challenging task in industry. The properties of the constituent materials, fiber orientation and the stacking sequence of laminated composite materials could cause high attenuation of ultrasound signals. Ultrasonic testing is based on the interpretation of the reflected ultrasound signals when a transducer imposes ultrasound waves (pulse) to a material. It is difficult to differentiate if the reflected signal is induced from the defects, fiber content or the intermediate layers of GFRP composites. Most of the time, the drastic attenuation of signals could enshroud the modest changes in the reflected signals from defects. The purpose of this paper is to investigate the influence of fiber orientation, thickness and delamination of GFRP composites on the rise time, pulse duration and attenuation ratio of the reflected ultrasound signal. The rise time, pulse duration and attenuation ratio of A-scan data was observed with respect to different positions of damage (delamination), thickness and stacking sequence of the lamina. It is essential to identify the significant factors that contribute to the abnormal characteristics of the reflected signals in which the defect is identified. Moreover, this paper presents the application of Taguchi method for maximizing the detection of defect in GFRP composites influenced by delamination. The optimum combination of the significant contributing factor for the signal's abnormal characteristics and its effect on damage detection was obtained by using the analysis of signal-to-noise ratio. The finding of this study revealed that delamination is the most influential factor on the attenuation ratio.

3

The definition of dissipative composite characteristics on the basis of nonlinear damping effects

Marchuk M., Salyak B., Pakosh V., Yakimov F.

Vibrations in Physical Systems

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2006

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Vol. 22

257--264

EN

The work is devoted to the experimental investigations of dissipative properties and damage of composite materials. The experimental technique is based on the measurement of the phase, amplitude and frequency characteristics of prismatic specimens subjected to dynamic excitation. The theoretical foundations of the method and the experimental results related with nonlinear damping effects are discussed. The presented experimental data certain conclusions about delamination damage of composite material can be drawn.