• Structural Engineering and Mechanics
• /
• v.85 no.5
• /
• pp.665-677
• /
• 2023

In the present study, the limit point buckling and postbuckling behaviors of sinusoidal, shallow arches with pinned supports subjected to localized sinusoidal loading, based on the Euler-Bernoulli beam theory, are numerically analyzed. There are some studies on the buckling of sinusoidal shallow arches under the effect of sinusoidal loading. However, in these studies, the sinusoidal loading acts along the horizontal projection of the entire shallow arch. No study has been found in the relevant literature pertaining to the stability of the shallow arches subjected to various lengths of sinusoidal loading. Therefore, the purpose of this paper is to contribute to the literature by examining the effect of the length of the localized sinusoidal loading and the initial rise of the shallow arch on the limit point buckling and postbuckling behaviors. Equilibrium paths corresponding to certain values of the length of the localized sinusoidal loading and various values of the initial rise parameter are presented. It has been observed that the length of the sinusoidal loading and the initial rise parameter affects the transition from no buckling to limit point instability remarkably. The deformed configurations of the sinusoidal shallow arch under localized loading regarding buckling and postbuckling states are illustrated, as well. The effects of the length of the localized sinusoidal loading on the internal forces of the shallow arch are investigated during various stages of the loading.

• Journal of information and communication convergence engineering
• /
• v.8 no.5
• /
• pp.566-569
• /
• 2010

This paper describes the sinusoidal, pulse, triangular oscillator using second generation current conveyor. To obtain the sinusoidal waveform the circuit blocks are constructed by using all pass filter and integrator. The pulse and the triangular waveforms are obtained from the output of sinusoidal oscillator. The peak-to-peak voltages of sinusoidal and triangular waveforms can be easily controlled by the dc offset voltage. Also the output frequency of the oscillator can be controlled by varying passive elements. The designed circuit is verified by HSPICE simulation.

• Journal of computational fluids engineering
• /
• v.19 no.4
• /
• pp.1-7
• /
• 2014

A numerical study of transient conjugate heat transfer on micro heater in a micro-channel substrate under a sinusoidal heat load was conducted. It was found that the time constant is not affected by the maximum heating magnitude of the sinusoidal heat load. However, the time constant increases with low duration of the sinusoidal heating period and low Reynolds number. Moreover, there is a threshold where a heater temperature do not reach to time constant at low thermal diffusivity, low flow rate, and low pulse duration of the sinusoidal heating. The time constant should be considered for transient convective heat transfer under transient sinusoidal heat load in a micro heat sink.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.16 no.8
• /
• pp.691-697
• /
• 2004

Experimental study is carried out to investigate the heat transport capability and thermal resistance of sinusoidal axially grooved heat pipe, comparing its performance to trapezoidal axially grooved heat pipe. As a result from this work, the heat transport capability of sinusoidal grooved heat pipe is lower than that of trapezoidal grooved heat pipe for the same size of outer diameter. As the ratio of depth to width of sinusoidal groove heat pipe is higher, the heat transport capability of heat pipe becomes higher. It is found that Aluminum-ammonia heat pipes with sinusoidal and trapezoidal grooves have good thermal resistance, below 0.1$^{\circ}C$/W at evaporator section and below 0.05$^{\circ}C$/W at condenser section.

• Journal of the Korean Professional Engineers Association
• /
• v.22 no.4
• /
• pp.12-16
• /
• 1989

This paper presents a n analysis of the output voltage waveforms of the double sinusoidal modulated PWM inverter, and are studied on the driving characteristics through the 3 phase induction motor using 6502 microcomputer. The double sinusoidal modulated waves are produced during the interval 4$\pi$/3 [rad] for one cycle, and the switching loss can be reduced. The amplitude of fundamental wave of double sinusoidal modulated PWM inverter is 1.15 times higher than that of the sinusoidal PWM inverter, but the practical measured value by FFT analyzer is 1.13 times.

• Proceedings of the KIEE Conference
• /
• 1994.07a
• /
• pp.582-584
• /
• 1994

A sinusoidal rotatory chair system using a self-tuning and following control by a fuzzy was designed to evaluate the vestibular function and to apply to a robot driving power system. The experimental results by the sinusoidal rotatory chair system were pretty good and whitch had smaller then ${\pm}210$ pulse error on the ${\pm}810^{\circ}$ sinusoidal rotation at 0.12 Hz by using a 850W DC servo motor. As a results, the sinusoidal rotatory chair system may be useful to evaluate the vestibular function in the field of medicine, and it can be used to robotics or a numerical control system (NC) on the industry if the the obtained control method and the system are adapted for a channel.

• Speech Sciences
• /
• v.7 no.1
• /
• pp.17-29
• /
• 2000

The STC(Sinusoidal Transform Coding) is a vocoding technique that uses a sinusoidal speech model to obtain high- quality speech at low data rate. It models and synthesizes the speech signal with fundamental frequency and its harmonic elements in frequency domain. To reduce the data rate, it is necessary to represent the sinusoidal amplitudes and phases with as small number of peaks as possible while maintaining the speech quality. As a basic research to develop a low-rate speech coding algorithm using the sinusoidal model, in this paper, we investigate the speech quality depending on the number of sinusoids. By varying the number of spectral peaks from 5 to 40 speech signals are reconstructed, and then their qualities are evaluated using spectral envelope distortion measure and MOS(Mean Opinion Score). Two approaches are used to obtain the spectral peaks: one is a conventional STFT (Short-Time Fourier Transform), and the other is a multiresolutional analysis method.

• Journal of Aerospace System Engineering
• /
• v.3 no.2
• /
• pp.20-23
• /
• 2009

The structural analysis of liquid rocket engine was performed in the case of sinusoidal vibration load to verify structural safety. The finite element model is composed with main liquid rocket engine components, combustion chamber, turbopump, gas-generator, pyro-starter, main pipes, main valve, heat-exchanger, gimbal-mount and brackets. Natural vibration mode analysis and structural analysis for sinusoidal vibration load were performed. The natural mode frequency of liquid rocket engine is twice than that of launch vehicle. In the case of stress result of sinusoidal vibration load, the part of maximum stress has 1.4 margin, so the engine structure is safe for sinusoidal vibration load.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.9 no.2 s.25
• /
• pp.136-142
• /
• 2006

A damped sinusoidal electromagnetic pulse generator was designed, fabricated and tested. The pulse generator consisted of an oscillator(a spark gap switch and an initially charged low impedance line) and a high impedance antenna. This generator was capable of producing damped sinusoidal pulses at closure of the spark gap switch. A Marx generator was employed to supply the Pulse generator with high voltage pulses. While the pulse generator was provided with the high voltage pulses of 200kV from the Marx generator, its output power was maximized by controlling the pressure of the gas contained in the spark gap switch. The output power of the damped sinusoidal electromagnetic pulse oscillator was 1.3GW and the amplitude of electric field radiated from the pulse generator was 4kV/m at the range of 25m.

• Steel and Composite Structures
• /
• v.18 no.2
• /
• pp.325-344
• /
• 2015

Experimental tests on cellular beams with sinusoidal openings showed two main failure modes around the openings. They concern the formation of four plastic hinges and the local instability of the sinusoidal part of the opening. In parallel, numerical analysis of the sinusoidal part of the opening revealed the existence of an elastic rotational restraint between the intermediate web-post and the adjacent opening panel. The aim of the present study is to present an approach to quantify this rotational restraint. Through the response surface method, a mathematical model is proposed. It shows a great ability to predict the rotational restraint value as a function of the geometrical parameters of the opening. This model can be used to perform an extensive study with various geometrical configurations of beams with the aim to develop a reliable and realistic analytical model predicting the resistance of the sinusoidal openings.