A prismatic beam made of a behaviorally nonlinear material is analyzed under aharmonic load moving with a known velocity. The vibration equation of motion is derived usingHamilton principle and Euler-Lagrange Equation. The amplitude of vibration, circular frequency,bending moment, stress and deflection of the beam can be calculated by the presented solution.Considering the response of the beam,...

Abstract: It is assumed that a beam made of material has a physical nonlinear behavior. This beam is analyzed under the moving concentrated and distributed continuous loads. The vibration equations of motion are derived from the Hamilton's Principle and Euler–Lagrange Equation. In this study, the amplitude of vibration, circular frequency, bending moment, stress and deflection of the beam has b...

Finite element formulations based generally on classical beam theories such as Euler-Bernoulli or Timoshenko. Sometimes, these two formulations could be problematic expressed in terms of restrictions of Euler-Bernoulli beam theory, in case of thicker beams due to non-consideration of transverse shear; phenomenon that is known as shear locking characterized the Timoshenko beam theory, in case of...

The static pull-in instability of beam-type micro-electromechanical systems is theoretically investigated. Two engineering cases including cantilever and double cantilever micro-beam are considered. Considering the mid-plane stretching as the source of the nonlinearity in the beam behavior, a nonlinear size-dependent Euler-Bernoulli beam model is used based on a modified couple stress theory, c...

background: in diagnostic radiology lead apron, are usually used to protect patients and radiology staff against ionizing radiation. lead apron is a desirable shield due to high absorption and effective attenuation of x-ray photons in the diagnostic radiology range. objective: although lead aprons have good radiation protection properties, in recent years, researchers have been looking for alte...

Studying Gaussian beam is a method to investigate laser beam propagation and ABCD matrix is a fast and simple method to simulate Gaussian beam propagation in different mediums. Of the ABCD matrices studied so far, reflection and refraction matrices at various surfaces have attracted a lot of researches. However in previous work the incident beam and the principle axis of surface are in parallel...

introduction: vertical root fracture (vrf) is common in endodontically treated teeth. conventional and digital radiographies have limitations for detection of vrfs. cone-beam computed tomography (cbct) offers greater detection accuracy of vrfs in comparison with conventional radiography. this study compared the effects of metal artifacts on detection of vrfs by using two cbct systems. methods a...

odontogenic myxoma (om) is an infiltrative benign bone tumor that occurs almost exclusively in the facial skeleton. the radiographic characteristics of odontogenic myxoma may produce several patterns, making diagnosis difficult. cone-beam computed tomography (cbct) may prove extremely useful in clarifying the intraosseous extent of the tumor and its effects on surrounding structures. here, we r...

background and aims. the imaging techniques commonly used for foreign body detection include plain radiography, xeroradiography, computed tomography (ct) scans, magnetic resonance imaging (mri) and ultrasonography. the aim of the present study was to compare cone-beam computed tomography (cbct) with conventional ct scan in determination of the exact location of a foreign body in the maxillofaci...