SOME PECULIARITIES OF THE INSTALLATION, DESIGN AND CALCULATION OF HINGE BOLT CONNECTIONS IN THE FLOWS OF STEEL DOUBLE BEAMS IN THE RECONSTRUCTION OF BUILDINGS

Formulation of the problem. The object of study is steel beams of technological sites and coatings of buildings under static load. Statically indeterminate beams of the 1st class (according to the classification given in DBN B.2.6-198:2014) are considered, for which as a result of the reconstruction of the building provided in the project, increase in intensity of loading increase of bearing capacity of beams is required. The analysis of the existing ways of increase of bearing capacity of beams without strengthening by a method of increase in cross sections, namely, vertical movement of supports of a beam, the device of artificial hinges in beams of a beam is resulted. These methods allow the adjustment of the forces in the beam so that the bending moments in the run and the support section are the same in absolute value, which is less than the maximum bending moment in the beam before the adjustment of the forces. The problem is the design of the bolted hinged connection of the suspension beam with the cantilever beam without dismantling the beam stored for further operation, or without the installation of temporary supports in the joint area. The purpose of the article. Identify and take into account the features of the location, calculation, design and execution of hinged bolted joints in the beams saved for further operation of the beams without their dismantling. Conclusion. The design of the hinged bolted connection of the suspended beam with the cantilever has been developed. The walls of the suspension and cantilever beams are connected so that on one side of the joint the bolts are located in one vertical row, which provides free rotation of the cross sections of the suspension and cantilever beam with sufficient, determined by calculation, the difference between the diameters of holes and bolts. One vertical row of bolts should be placed in the wall of the suspension beam, for the strength of the bolted connection of the pads. An example of construction and calculation of a hinged cantilever beam formed from an integral two-span beam during the reconstruction of the building is given.

Influence of Impulse Force Loading on Vibrations of the Collecting Electrodes

Results of the simulations of vibrations of collecting electrode system of dry electrostatic precipitator (ESP) are reported. The system of nine electrodes 16[Formula: see text]m long, suspension beam (upper beam) and anvil beam (bottom beam) is analyzed. First, the variants regarding differ position of the anvil beam are analyzed. Second, the differ position of a point of the impulse force as well as direction of the impulse force are investigated (in this case the anvil beam is in a “classic” position). Discretization of both beams and electrodes is carried out employing the modified rigid finite element method (RFEM). It allows to study an influence of the mass distribution and geometric properties of the analyzed system. Moreover, the method is convenient for the introduction of additional lumped mass parameters modeling the joints that fasten the electrodes to the suspension beam, distance-marking bushes, riveted and screw joints, etc. Position of the anvil beam and position/direction of the point of impulse force application can have essential influence on tangent and normal accelerations at different points of the plates, and thus on the effectiveness of the dust removal process. We aim to find optimal position of an anvil beam, which guaranties the maximum amplitudes of vibrations and their proper distribution in the plates.

A Microactuator for Tracking Servo

To achieve higher data track density of a hard-disk drive (HDD), a microactuator that is placed between suspension beam and a slider and moves slider relative to suspension was investigated. This paper presents new microactuator design, “bipolar microactuator” and its performance in a hard-disk drive.

3 KHz Servo Bandwidth Demonstration by HDD Tracking Microactuator

A demonstration of a closed loop system with a 3 kHz 0 dB open loop crossover using a microactuator in an HDD is reported. An electrostatic rotational microactuator is placed between the suspension beam and the slider, and moves the slider relative to the suspension. A new suspension with extra leads that provide signal to the microactuator was also developed. These leads are electrically connected by a micro-scale solder-ball reflow process. The dual-stage servo experiment was carried out in an HDD and a 3 kHz servo bandwidth was achieved, which is more than twice as high as a conventional servo system. The error rejection function also shows that this dual-stage servo system has superior error rejection capability over the conventional VCM-only servo system. Simulation shows that the bandwidth can be as high as 44 kHz, if a continuous-time servo is used.