In this paper, hydroforming process of bent tubes in T-shaped die is studied for pulsating and linear pressure paths by the finite element method. Forming Limit Diagrams (FLDs) and thickness distribution curves are used to investigate the effect of pulsating pressure on hydroforming process. In addition, the obtained numerical results are compared with experimental results of hydroforming of st...

In this paper, the laser bending process of a circular tube made of mild steel has been investigated experimentally. For this purpose, the effects of the irradiating length and the number of irradiating passes on the main bending angle of a laser bent tube are studied. In addition, the main defects of the laser tube bending process such as lateral bending angle, ovality and thickness variation ...

The laser tube bending process (LTBP) is a thermal non-contact for tubes with less springback and thinning of the tube. In this paper, will be studied experimentally. length irradiation scheme are two main affecting parameters in LTBP process. For purpose, different samples according to schemes (Circular irradiating (CIS) axial (AIS)) lengths beam (from 4.7 28.2 mm) fabricated. angle laser-bent...

The smaller the relative bending radius of bent tube, more difficult tube blank is to be bent. In this paper, push-bending process for aluminum with a 0.9D was analyzed through simulation. There tangential tensile stress concentration occurring at front endpoint intrados, which increased risk cracking. That because tube’s extrados moves less angular distance than its intrados by uniform lubrica...

In order to decrease the fluid dynamic forces of the U-bent tube with a circular section and avoid the occurrence of fluid-structure interaction problems, three-dimensional simulations of fluid flows around the tubes are carried out. In the case that the axis of the curved tube with the circular section is prevented from being normal to the direction of the flows approaching the tube, the forma...

Dirichlet Laplacian on curved tubes of a constant cross section in two and three dimensions is investigated. It is shown that if the tube is non{straight and its curvature vanishes asymptotically, there is always a bound state below the bottom of the essential spectrum. An upper bound to the number of these bound states in thin tubes is derived. Furthermore, if the tube is only slightly bent, t...

Heat transfer enhancement in tubes is widely applied various industrial processes. The traditional method of heat to insert radial fins expand the internal surface area and destroy flow. However, there a flue gas corridor central tube, cost expanding inner fin high. A centrally symmetrical bent extruded aluminum was developed enhance tube. An experimental platform constructed test performance f...

In this Letter, we demonstrate a strong dependence of the electrostatic deformation of doubly clamped single-walled carbon nanotubes on both the field strength and the tube length, using molecular simulations. Metallic nanotubes are found to be more sensitive to an electric field than semiconducting ones of the same size. For a given electric field, the induced deformation increases with tube l...

straight 75 / 31 123 / 33 170 / 158 169 / 211 180 / 194 bent 129 / 76 154 / 96 159 / 136 194 / 180 213 / 136 Table 1: Number of streamlines approx. 15 cm upstream / downstream from the emitter plane (400 emitters) in the middle of the straight and bent tube. The number of streamlines reaching the inflow and outflow plane (dotted white line in figure 2 and 3) increased for each correction method...

The enlarged adenoid serves as a mechanical obstacle on the nasopharynx to intricate nasotracheal intubation. No matter what video or direct laryngoscopic techniques are applied, nasotracheal tube navigation from the nasal valve area through the nasal cavity to the nasopharynx is always blind; trauma is not uncommon. Here we report a case of unintended avulsed adenoids that plugged the tube tip...