جستجوی مقالات مرتبط با کلیدواژه "پاسخ گذرا" در نشریات گروه "مکانیک"

In this paper, a commercial metal-oxide gas sensor was first placed under temperature modulation regime and simultaneously their transient response to various concentrations of ethanol vapors was recorded. By applying the temperature modulation, the sensor surface temperature was also recorded by a S-type thermocouple. Then, the performance of these sensors was expressed based on the both air oxygen absorption model and ethanol absorption on the surface of the sensitive layer using the Freundlich isotherm equation. Further, this model is simulated using the MATLAB software in the simulink environment. Using this model, one can see the sensor's dynamic response to ethanol. In this model, the concentration of a gas is considered as a voltage. This parameter, along with the temperature profile of the sensor surface under temperature modulation and sensor conductance under the influence of air oxygen, are considered as inputs of the model and transient response of the sensor as output of the model. The parameters of this model are calculated based on the approximate criterion of simulated responses and the responses recorded for each concentration of ethanol gas. The simulation results based on the average simulated parameters also showed that the simulated responses were close to the actual recorded responses.

Dynamic response (transient vibration) of a magnetorheological elastomer (MRE) based simply supported sandwich beam under various transient loads is investigated. The MRE is modeled as a Kelvin-Voigt viscoelastic material. Hamilton’s principle in conjunction with the classical Euler-Bernoulli beam equations and linearized compatibility relations of sandwich beams with transversely flexible cores is used to derive the equations of motion and pertaining boundary conditions. Fourier series and Durbin’s algorithm for the inversion of Laplace transform are used to solve the equations of motion for different transient loads (i. e. impulse، moving load، and uniformly distributed harmonic load) in different magnetic fields. Limiting cases are compared with the data in the classic literature as verification.