• 한국포장학회지
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• 제12권1호
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• pp.21-25
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• 2006

Measurements of accelerometer levels transmitted from the floor in commercials truck shipments were carried out transportation of 300 Kg-load from Gyungbu Highway(Waegouan-Seoul) to 88 Highway(Gwangju-Daegu). Different characteristics were observed the values measured the vibration levels with directions in the two Highway's as a function of road condition and truck speed. The results showed that the vibration levels of the Gyungbu Highway is much higher than those of the 88 Highway. A following analysis on the obtained values was used to get the acceleration spectral density (ASD) and power spectral density (PSD). For the entire transit route, the results showed that the level of vibration to vertical direction was significant effects for damaging the products carried compared to other directions such as longitudinal and transverse. This paper provides an updated history of measured characteristics of vibration levels for highways using mainly in domestic area.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.1047-1051
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• 2004

Charge amplifier systems benefit from the very wide dynamic range of PE accelerometers by offering flexibility in adjusting the electrical output characteristics such as sensitivity and range. They are well suited for operation at high temperatures. Modern charge systems feature improved low noise operation, simplified digital controls, and dual mode operation for operation with charge or IEPE voltage mode sensors. high impedance circuitry is not well suited for operation in adverse field or factory environments. The resolution of a PE accelerometer may not be specified or known since noise is a system consideration determined by cable length and amplifier gain. IEPE accelerometrs operate from a constant current power source, provide a high-voltage, low-impedance, fixed mV/g output. They operate through long, ordinary, coaxial cable in adverse environments without degradation of signal quality. They have limited high temperature range. IEPE sensors are simple to operate. Both resolution and operating range are defined specifications. Cost perchannel is lower compared to PE systems since low-noise cable and charge amplifiers are not required.

• International Journal of Ocean System Engineering
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• 제2권3호
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• pp.151-159
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• 2012

The characteristics of an impact load and pressure were experimentally investigated. Drop tests were carried out using a modified Wigley with CB = 0.56. The vertical force, pressures, and vertical accelerations were measured. A 6-component load cell was used to measure the forces, piezo-electric sensors were used to capture the impact pressure, and strain-gauge type accelerometers were used to measure the vertical accelerations. A 50-kHz sampling rate was applied to capture the peak values. The repeatability of the measured data was confirmed and the basic characteristics of the impact load and pressure such as the linearity to the falling height were observed for all of the measurements. A simple formula was derived to extract the physical impact load from the measured force based on a simple mass-sensor-mass diagram, which was validated by comparing impact forces with existing data using the mathematical model of Faltinsen and Chezhian (2005). The effects of the elasticity of the model and change in acceleration during the water entry were investigated. It is interesting to observe that the impact loads occurred and reached peak values at the same time duration after water entry for all drop heights.