Journal articles on the topic 'Beam dividers'
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1
Klein, Tobias, Peter Uhlig, Carsten Günner, and Reinhard Kulke. "Substrate-integrated divider networks in LTCC with optimized tolerance / isolation properties for Ka-Band satellite systems." International Symposium on Microelectronics 2014, no. 1 (October 1, 2014): 000816–19. http://dx.doi.org/10.4071/isom-thp22.
Abstract:
Low Temperature Cofired Ceramics (LTCC) technology is increasingly used for creating high-rel solutions, especially in class S products deployed in space. Current research, executed by the german and european space agencies, focuses inter alia on new, compact beam forming networks for Ka-band multiple feed per beam antennas. These networks consist of a high number of dividers and must provide a high isolation between neighbouring cells to ensure compliance with frequency plan regulations. While the LTCC process brings a number of advantages, its thick film printing process and the tolerances of available resistive paste systems introduce difficulties in implementing typical Wilkinson divider networks. This paper presents a novel concept to implement tolerance-optimized dividers, taking special focus on the properties of the LTCC process.
2
Li, Chong, Lai Bun Lok, Ata Khalid, Vasileios Papageorgiou, James Grant, and David R. S. Cumming. "Millimeter-wave coplanar stripline power dividers." International Journal of Microwave and Wireless Technologies 5, no. 3 (May 1, 2013): 205–12. http://dx.doi.org/10.1017/s1759078713000421.
Abstract:
We present the design, fabrication, and measurement of a 2-way modified Wilkinson divider constructed in a coplanar geometry exhibiting ultra wideband isolation, transmission, and port matching in the millimeter-wave frequency range. The proposed divider replaces the lumped resistor in the conventional Wilkinson divider with two quarter-wave length transmission lines, a phase inverter, and two 2Z0 resistors. Except for the three ports that are coplanar waveguides (CPWs), the main body of the divider uses coplanar striplines (CPS). The phase inverter is realized using a simple airbridge-based crossover which is compatible with a modern monolithic microwave integrated circuit process. The divider has a ring-like configuration fabricated on a 620 µm thick semi-insulating GaAs wafer using electron beam lithography (EBL) technology. Three-dimensional (3D) full-wave electromagnetic simulations have been carried out to optimize the design and investigate the possible effect of fabrication tolerance on the performance of the crossover and the divider. Two dividers working at center frequencies of 25 and 80 GHz have been designed, fabricated, and tested. They all show consistent performance in terms of bandwidth, isolation, and port matching. Experimental and simulation results are in excellent agreement.
3
Boutayeb, Halim, Paul R. Watson, Weishan Lu, and Tao Wu. "Beam Switching Dual Polarized Antenna Array With Reconfigurable Radial Waveguide Power Dividers." IEEE Transactions on Antennas and Propagation 65, no. 4 (April 2017): 1807–14. http://dx.doi.org/10.1109/tap.2016.2629469.
4
Yip, G. L., and M. A. Sekerka-Bajbus. "Design of symmetric and asymmetric passive 3-branch power dividers by beam propagation method." Electronics Letters 24, no. 25 (1988): 1584. http://dx.doi.org/10.1049/el:19881080.
5
Rudakov, Viacheslav, and Victor Sledkov. "Development of antenna arrays with a beam width 33 degrees at the level of half power." ITM Web of Conferences 30 (2019): 05030. http://dx.doi.org/10.1051/itmconf/20193005030.
Abstract:
A new design of the antenna array for mobile base stations providing two orthogonal polarizations in 1.71-2.17GHz frequency band is proposed. The antenna array includes 16 radiators, 12 power dividers and two phase shifters disposed on a metal reflector having dimensions 320×1387 mm. The developed antenna array contains less radiators and power dividers than other known antennas of this kind therefore one is cheaper for production. The fabricated sample of the proposed antenna array has return loss is better than -18.5dB and isolation better than 33dB. Beam width in the horizontal plane is equal 36 ± 4 degrees and side lobes level doesn’t exceeding -20dB. The antenna array provides gain=20.5dBi.
6
Van Trinh, Thai, Son Trinh-Van, Kang-Yoon Lee, Youngoo Yang, and Keum Cheol Hwang. "Design of a Low-Cost, Low-Sidelobe-Level, Differential-Fed SIW Slot Array Antenna with Zero Beam Squint." Applied Sciences 12, no. 21 (October 25, 2022): 10826. http://dx.doi.org/10.3390/app122110826.
Abstract:
This paper presents a low-cost, low-sidelobe-level, differential-fed, substrate-integrated waveguide (SIW)-based slot array antenna with zero beam squint. The antenna consists of two identical six-way unequal power dividers (PDs) and a 6 × 16 slot array and is realized on a single-layer substrate. The six-way unequal PD provides tapered amplitude and in-phase excitation for six SIWs, and each of them has 16 radiating slots. The 1 × 16 linear slot array on each SIW is excited using a differential feed to avoid undesired beam squinting across its operating band. A two-way hybrid waveguide (WG)-to-SIW E-plane PD is developed to provide equal amplitude and out-of-phase excitation for two six-way unequal power dividers. Moreover, metallic decoupling walls are implemented between two adjacent linear slot arrays to reduce E-plane external mutual coupling. An antenna prototype is fabricated and experimentally verified. The fabricated antenna shows that the measured −10 dB reflection bandwidth is 7.15% (9.57–10.28 GHz), with the achieved gain ranging from 20.30 to 21.92 dBi. A stable boresight beam is observed over the entire operating band. Furthermore, at the designed frequency of 10 GHz, peak SLLs of −29.1 dB and −29.4 dB are achieved in the E- and H-plane, respectively.
7
Salem Hesari, Sara, and Jens Bornemann. "Antipodal Vivaldi Antenna Arrays Fed by Substrate Integrated Waveguide Right-Angled Power Dividers." Applied Sciences 8, no. 12 (December 14, 2018): 2625. http://dx.doi.org/10.3390/app8122625.
Abstract:
This paper describes a novel feed system for compact antipodal Vivaldi antenna arrays on a single layer of substrate integrated waveguide (SIW) by using SIW H-plane right-angled power dividers. The proposed antenna systems are composed of a Vivaldi array and an H-plane right-angled corner power divider which includes an over-moded waveguide section. Based on the number of antennas in the Vivaldi array, mode converter sections at K-band and Ka-band frequencies are designed, fabricated, and measured when feeding Vivaldi antenna arrays with two, three, and four antennas. Right-angled SIW power dividers are employed to obtain controllable phase distribution over the output ports which consequently controls the beam shapes of the systems. The phase relationships in the output ports are varied to obtain different pattern directions for different applications. The two-way divider system with 180-degree phase difference and three-way divider system are fabricated and measured; simulation results are presented for other designs. The measured results are in good agreement with simulations which confirms the design approach. All systems achieve good performance and meet all design goals including a return loss better than 10 dB in the operating bandwidth, gain higher than 8 dB for all systems, and radiation and polarization efficiencies higher than 80% and 98%, respectively.
8
FIELDS, C. H., M. SOKOLICH, S. THOMAS, K. ELLIOT, and J. JENSEN. "Progress toward 100 GHz Logic in InP HBT IC Technology." International Journal of High Speed Electronics and Systems 11, no. 01 (March 2001): 217–43. http://dx.doi.org/10.1142/s0129156401000836.
Abstract:
Future wideband communications, mm-wave digital synthesis, and digital beam-steering will benefit from digital operation at clock frequencies between 50 and 100 GHz at reasonable power levels. HRL has developed InP-based HBT technology that is capable of supporting these needs. We have demonstrated InP HBTs with cutoff frequencies, ft, over 200 GHz and with f max over 300 GHz as well as fully static dividers operating at 72.8 GHz.
9
Arce, Armando, Enrique Stevens-Navarro, Ulises Pineda-Rico, Marco Cardenas-Juarez, Francisco R. Castillo-Soria, and David H. Covarrubias. "Optimization of a Coherent Dual-Beam Array Feed Network for Aperiodic Concentric Ring Antennas." Applied Sciences 11, no. 3 (January 26, 2021): 1111. http://dx.doi.org/10.3390/app11031111.
Abstract:
A dual-beam coherent feeding system design approach with a non-uniform layout on a concentric ring array is described and synthesized. In this case, the feeding system is based on a reconfigurable topology composed of a set of alternated power dividers and combiners, providing coherent in-phase outputs. Thus, in this paper, a two-beam architecture based on a coherent feeding system formed by a set of intercalated input signals feeding each circular ring in a non-uniform antenna array with multi-beam shaping and steering features is analyzed. The task of optimizing the aperiodic layout on the shared aperture based on the radii of the circular rings is realized by the differential evolution method. Numerical experiments grounded in antenna synthesis validate the capabilities and improved performance of the proposed dual-beam configuration with a non-uniform layout in contrast with its uniform counterpart, with enhanced performance on average by up to −6.1 dB for sidelobe level and 3.5 dB for directivity. Additionally, the results show a significantly less complex two-beam feeding network in contrast with the case of a typical electronically scanned array—in this proposal, each direction of maximum radiation is conformed and scanned with approximately half of the control inputs.
10
Yan, Lei, Wenbin Zou, Kaihong Zheng, Guangli Yang, and Yong Luo. "A Dual-Polarized CTS Array Antenna with Four Reconfigurable Beams for mm-Wave Wind Profile Radar." Electronics 13, no. 1 (January 4, 2024): 238. http://dx.doi.org/10.3390/electronics13010238.
Abstract:
The wind profiler radar (WPR) system requires a dual-polarized antenna with multiple low-sidelobe and high-gain beams to facilitate the detection of weak signals reflected by atmospheric turbulence. This paper proposes a dual-polarized continuous transverse stub (CTS) K-band antenna with four reconfigurable beams, which comprises a series-fed CTS array and four 1-to-14 power dividers as line source generators (LSGs) to generate a high-quality quasi-TEM wave. The CTS element incorporates a stepped transition radiation stub design and employs a short cutoff stub on the upper surface of the series-fed parallel plate waveguide (PPW) to achieve optimal impedance matching. The entire antenna is an all-metal structure with remarkably low loss, and low-cost standard fabrication processes are employed for the prototype, which achieves fast reconfigurable four-beam scanning to 15°, with a gain of 31.09 dBi and sidelobe levels below −17.6 dB. Measurement results in an anechoic chamber agree well with simulations, demonstrating the antenna’s ease of manufacture, stability, and suitability for wind profile radar applications.
11
Jin-Liang Liu, Bing Ye, Tian-Wen Zhan, Jia-Huai Feng, Jian-De Zhang, and Xin-Xin Wang. "Coaxial Capacitive Dividers for High-Voltage Pulse Measurements in Intense Electron Beam Accelerator With Water Pulse-Forming Line." IEEE Transactions on Instrumentation and Measurement 58, no. 1 (January 2009): 161–66. http://dx.doi.org/10.1109/tim.2008.927195.
12
Arce, Armando, Marco Cardenas-Juarez, Ulises Pineda-Rico, David H. Covarrubias, and Enrique Stevens-Navarro. "A Multiple Beamforming Network for Unequally Spaced Linear Array Based on CORPS." International Journal of Antennas and Propagation 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/757989.
Abstract:
This paper proposes an alternative and innovative way to design a simpler beamforming network (BFN) based on balancing alternated power combiners and dividers, to feed a nonuniformly spaced linear array with Gaussian amplitude and coherent (in-phase) signals. Thus, a two-beam design configuration of the feeding network for a nonuniform array with beam steering capability is proposed and analyzed. The nonuniform aperture and the complex inputs of the feeding network are optimized by means of a differential evolution algorithm. In addition, a comparative analysis between a uniform and nonuniform linear array with the proposed feeding network is performed. Simulation results show the advantages and effectiveness of the proposed feeding network exploiting the nonuniformity of the antenna elements, in terms of side lobe level and directivity. Furthermore, research results show an inherent reduction in hardware complexity of the network.
13
Tengah, Zanurlida, Nurul Huda Abd Rahman, Yoshihide Yamada, and Suhaila Subahir. "DESIGN OF CONVEX AND CONCAVE DUAL BENT ARRAY FOR 5G LENS ANTENNA SYSTEM." ASEAN Engineering Journal 12, no. 3 (August 31, 2022): 143–48. http://dx.doi.org/10.11113/aej.v12.17326.
Abstract:
Previous research on the multi-beam system for the fifth generation (5G) application has shown that the number of feed elements of a lens antenna system at the mobile base station is increasing due to the massive MIMO requirements. The design of the array circuits of the 5G lens antenna systems will be more complicated due to the feeding structure, which consists of the power dividers and phase shifters, thus contributing to higher feeding losses. The antenna fabrication process also becomes more complicated. Besides that, the conventional array feed also produces a single radiation beam only. Thus, a large space is needed, where array feed antennas should be arranged to perform wide-angle beam scanning for 5G massive MIMO operation. Therefore, to overcome these issues, this paper uses a bent array configuration as the lens antenna feed to produce bifurcated beam radiation and has a wide beam angle from the feed radiator to the lens edge. Multiple bent arrays are arranged on the lens axis to generate a multi-beam by cylindrical lens antenna. This paper shows a comparison of the bent array in convex and concave configurations. This process investigates the mutual coupling when more than one bent array is arranged as feed radiators. By comparing the arrays in convex and concave structures, it is observed that the convex structure produces a better-bifurcated beam with a smaller middle lobe. The antenna also produces the same bifurcated beam shifting angle, θs for both ports, when s = 4λ is used. It is verified as the optimum spacing value between two bent array structures by the optimization process.
14
Et. al., P. Venkat Ram Reddya,. "New Model Of Enhanced Plasticity For Reinforced Concrete Structural Elements That Take Into Account The Effects Of Lateral Loading And Gravity." Turkish Journal of Computer and Mathematics Education (TURCOMAT) 12, no. 2 (April 10, 2021): 1482–87. http://dx.doi.org/10.17762/turcomat.v12i2.1379.
Abstract:
Reinforced concrete structures are exposed to a progression of activities all through their life expectancy which may be the purpose behind damage. Subsequently, rehabilitation of existing structures is typically performed either to restore structural limit because of decay or damage or to broaden existing structural limit due to expanded loads. To fortify existing structures, numerous new creative materials like progressed fiber-reinforced polymers (FRPs) are discovered to be acceptable substitute for reinforcing materials like steel. They are actualized to fortify the presentation of structural components in flexure, pivotal, shear, and twist. In a RC outline, migrating plastic pivots in the beam off from the column face is normally prescribed to broaden pliability of the edge. This could be accomplished through rib reinforced FRP retrofit of the joint. Furthermore, to it, thus we execute an expanded pliancy for the concrete structural components like column, beam, chunk, dividers then on. The primary motivation behind a wide range of structural frameworks utilized in the structure type of structures is to transfer gravity and horizontal loads effectively.
15
Uddin, Md Nazim, and Sangjo Choi. "Non-Uniformly Powered and Spaced Corporate Feeding Power Divider for High-Gain Beam with Low SLL in Millimeter-Wave Antenna Array." Sensors 20, no. 17 (August 22, 2020): 4753. http://dx.doi.org/10.3390/s20174753.
Abstract:
A corporate feeding antenna array with parasitic patches has been investigated previously for millimeter-wave applications due to its high gain and wide bandwidth. However, the parasitic patch integration in the uniformly powered and spaced patch antenna array led to a high sidelobe level (SLL). In this study, we designed a non-uniformly powered and spaced corporate feeding network to feed a 12-element parasitic patch-integrated microstrip antenna array for SLL reduction at 28 GHz in the millimeter-wave band. In the power divider, we arranged two one-to-six unequally feeding power dividers from the opposite side to feed 12 antenna elements with non-uniform excitation, and effectively controlled the spacing between antenna elements. The two opposite input ports from the power divider were fed 180° out-of-phase for good isolation between the adjacent antenna elements. To verify the SLL reduction effect from the non-uniform spacing in the array, we designed two non-uniformly powered patch antenna arrays with uniform and non-uniform spacing. In the measurement, the non-uniformly powered and spaced patch antenna array demonstrated a nearly 16.56 dBi boresight gain and −17.27 dB SLL, which is nearly 2 dB lower than the uniformly spaced counterpart. Finally, we expect that the non-uniformly powered and spaced high gain patch antenna array with a low SLL will be suitable for millimeter-wave communication applications.
16
Arce, Armando, Enrique Stevens-Navarro, Marco Cardenas-Juarez, Ulises Pineda-Rico, Jorge Simon, and Marco A. Panduro. "Design and Optimization of a Coherent Beamforming Network for an Aperiodic Concentric Ring Array." International Journal of Antennas and Propagation 2019 (May 6, 2019): 1–10. http://dx.doi.org/10.1155/2019/4601718.
Abstract:
In this work, a flexible and reconfigurable feeding network design for a nonuniform aperture on circular concentric ring arrays is proposed and analyzed. The network subsystem delivers coherent in-phase outputs with a Gaussian-like amplitude distribution, in a modular and basic topology based on sets of alternated power combiners and dividers. A complete antenna system in a monobeam configuration with a coherent network based on grouped inputs (blocks) per ring for an aperiodic concentric ring array with beam scanning and beam shaping properties is synthesized and analyzed. Additionally, a comparative analysis based on nonuniform and uniform concentric ring arrays fed by the proposed coherent network configuration is conducted and assessed. The optimization of the aperiodic layout on the antenna aperture (radii and interelement antenna spacings) is done by the differential evolution algorithm. Numeric experimentation demonstrates the performance advantages and capabilities of the proposed coherent network configuration with a nonuniform aperture over its uniform counterpart, with an improvement in average equal to −8.7 dB of side lobe level and 3.9 dB of directivity. Furthermore, the numeric examples show a complexity reduction on the coherent feeding network configuration based on the number of control signal inputs compared with a conventional phased antenna array; in the proposed configuration, the main beam is steered and shaped with N-1 control feeding ports per ring in this antenna system.
17
Wang, Ke, Duo Zhang, Kunpeng Zhao, and Mei Wang. "2D asymmetric diffraction grating controlled by vortex light in double-Λ-type atomic system." Laser Physics Letters 21, no. 5 (March 20, 2024): 055201. http://dx.doi.org/10.1088/1612-202x/ad30f2.
Abstract:
Abstract A two-dimensional (2D) asymmetric diffraction grating controlled by vortex light in a double-Λ-type atomic system is studied. Such an atomic system is driven by a weak traveling-wave probe field and a signal field, a position-dependent strong standing-wave (SW) control field, and a Laguerre–Gaussian (LG) vortex field. Due to the asymmetric properties of the LG vortex field, the probe photons can be asymmetrically diffracted into four different domains after passing through the atomic media. The Diffraction patterns and intensities of the 2D asymmetric diffraction grating can be manipulated by the detuning of the probe field, the interaction length, and the intensity of SW control field. In addition, the relative phase and the azimuth parameter which is closely related to the vortex light also can be used to regulate the asymmetric diffraction grating effectively. This work may provide useful reference for optical information processing, especially for the design of optical beam dividers with desired intensities and novel quantum devices requiring asymmetric optical transmission.
18
Lü, Ze-Qi, Yan-Zhao Xie, Ming-Yue Gou, Xiao-Yu Chen, Jin-Shan Zhou, Mei Li, and Yi Zhou. "Development of 200 kV multi-function pulsed radiation system." Acta Physica Sinica 70, no. 20 (2021): 205206. http://dx.doi.org/10.7498/aps.70.20210583.
Abstract:
<sec>A multi-functional pulsed radiation system with a peak voltage of 200 kV, an impedance of 2 Ω, and a full width at half maximum (FWHM) of 30 ns is developed. The system can be switched flexibly in two states of generating pulsed electron beam and pulsed X-ray by changing the cathode and anode. It consists of a pulse power driving source, a vacuum diode, and an experimental cavity. A Marx generator, a high energy storage water transmission line, and two pulse compression switches are utilized to generate a high voltage on diode. An effector can be placed in the experimental cavity which has the same vacuum as diode. An insulation structure of transmission line and a diode are optimized to guide in system design. The system can provide a multi-functional experimental platform for investigating pulse power technology, system-generated electromagnetic pulse, biological radiation effect, etc.</sec><sec> The Marx generator generates a high-voltage pulse with hundreds of nanoseconds in FWHM and hundreds of kilovolts in peak value. The pulse is compressed by the main switch and pulse forming switch and then loaded to the diode. Electrons are emitted from diode cathode under the high-voltage pulse and accelerated in the gap. The electrons are extracted directly or converted into X-ray through the anode. Aluminized polyethylene is used as an anode when pulsed electron beam is generated, and tantalum film is used when pulsed X-ray is generated. Working state can be switched by changing the cathode and anode of diode.</sec><sec> The result shows that a current of 83 kA pulsed electron beam and an average energy of 67 keV X-ray are generated. Pulsed X-ray has good uniformity and low electron proportion (0.02%). In order to monitor the operation state and output parameter of the system comprehensively, a complete measurement system is established. Three capacitive voltage dividers are set at the beginning of transmission line, the end of pulse forming line, and the end of output line, while a B - dot current monitor is set at the diode. A Faraday cup is developed to measure the current intensity and the total energy of pulsed electron beam. For energy spectrum, dose and electron proportion, the measurement system composed of pulsed X-ray including spectrometric system, dose system and Rogowski Coil is build.</sec>
19
Lü, Ze-Qi, Yan-Zhao Xie, Ming-Yue Gou, Xiao-Yu Chen, Jin-Shan Zhou, Mei Li, and Yi Zhou. "Development of 200 kV multi-function pulsed radiation system." Acta Physica Sinica 70, no. 20 (2021): 205206. http://dx.doi.org/10.7498/aps.70.20210583.
Abstract:
<sec>A multi-functional pulsed radiation system with a peak voltage of 200 kV, an impedance of 2 Ω, and a full width at half maximum (FWHM) of 30 ns is developed. The system can be switched flexibly in two states of generating pulsed electron beam and pulsed X-ray by changing the cathode and anode. It consists of a pulse power driving source, a vacuum diode, and an experimental cavity. A Marx generator, a high energy storage water transmission line, and two pulse compression switches are utilized to generate a high voltage on diode. An effector can be placed in the experimental cavity which has the same vacuum as diode. An insulation structure of transmission line and a diode are optimized to guide in system design. The system can provide a multi-functional experimental platform for investigating pulse power technology, system-generated electromagnetic pulse, biological radiation effect, etc.</sec><sec> The Marx generator generates a high-voltage pulse with hundreds of nanoseconds in FWHM and hundreds of kilovolts in peak value. The pulse is compressed by the main switch and pulse forming switch and then loaded to the diode. Electrons are emitted from diode cathode under the high-voltage pulse and accelerated in the gap. The electrons are extracted directly or converted into X-ray through the anode. Aluminized polyethylene is used as an anode when pulsed electron beam is generated, and tantalum film is used when pulsed X-ray is generated. Working state can be switched by changing the cathode and anode of diode.</sec><sec> The result shows that a current of 83 kA pulsed electron beam and an average energy of 67 keV X-ray are generated. Pulsed X-ray has good uniformity and low electron proportion (0.02%). In order to monitor the operation state and output parameter of the system comprehensively, a complete measurement system is established. Three capacitive voltage dividers are set at the beginning of transmission line, the end of pulse forming line, and the end of output line, while a B - dot current monitor is set at the diode. A Faraday cup is developed to measure the current intensity and the total energy of pulsed electron beam. For energy spectrum, dose and electron proportion, the measurement system composed of pulsed X-ray including spectrometric system, dose system and Rogowski Coil is build.</sec>
20
Kumar, S., P. K. Gupta, R. K. Singh, R. Uma, and R. P. Sharma. "Self-compression of two co-propagating laser pulse having relativistic nonlinearity in plasma." Laser and Particle Beams 35, no. 4 (November 20, 2017): 722–29. http://dx.doi.org/10.1017/s0263034617000787.
Abstract:
AbstractThe study proposes a semi-analytical model for the pulse compression of two co-propagating intense laser beams having Gaussian intensity profile in the temporal domain. The high power laser beams create the relativistic nonlinearity during propagation in plasma, which leads to the modification of the refractive index profile. The co-propagating laser beams get self- compressed by virtue of group velocity dispersion and induced nonlinearity. The induced nonlinearity in the plasma broadens the frequency spectrum of the pulse via self-phase modulation, turn to shorter the pulse duration and enhancement of laser beam intensity. The nonlinear Schrodinger equations were set up for co-propagating laser beams in plasmas and have been solved in Matlab by considering paraxial approximation. The propagation characteristics of both laser beams inside plasma are divided into three regions through the critical divider curve, which has been plotted between pulse width τ01 and laser beam power P01. Based on the preferred value of critical parameters, these regions are oscillatory compression, oscillatory broadening, and steady broadening. In findings, it is observed that the compression of the laser beam depends on the combined intensity of both beams, plasma density, and initial pulse width.
21
Lyu, Yu-Ting, Tsung-Pin Hung, Her-Chang Ay, Hsiu-An Tsai, and Yih-Cherng Chiang. "Evaluation of Laminated Composite Beam Theory Accuracy." Materials 15, no. 19 (October 6, 2022): 6941. http://dx.doi.org/10.3390/ma15196941.
Abstract:
Carbon fiber-reinforced polymer (CFRP) has been widely implemented in electric vehicle bodies and aircraft fuselage structures. The purpose of CFRP is to reduce the weight and impart rigidity in the final product. A beam structure is typically used to bear the structural load, and the rigidity of the beam can be changed by arranging the laminated fibers at different angles. In this study, a composite I-beam is used as an example in engineering components. Because the theoretical model of the superimposed composite I-beam is established, the theoretical formula is based on the theoretical assumptions of the two-dimensional composite beam, and is combined with the traditional composite plate theory to analyze the maximum bending stress, strain, and deflection. During the theoretical derivation, it is assumed that the flanges of the I-beams are divided into narrow and wide flanges. The beams are considered as structures of beams and flatbeds. When a narrow flange is loaded in the side, the wide flange has no lateral deformation, and the lateral moments are neglected. Therefore, the accuracy of this formula needs to be verified. The purpose of this study is to verify the accuracy of theoretical solutions for the deflection and stress analysis of composite beams. A finite element analysis model is used as the basis for comparing the theoretical solutions. The results indicate that when the aspect ratio of the beam is >15, the theoretical solution will have better accuracy. Without the addition of the material, when 0° ply is placed on the outermost layer of the flange of the nonsymmetric beam, the effective rigidity of the beam is increased by 4–5% compared with the symmetrical beam. The accuracy range of the theoretical solution for the composite beams can be accurately defined based on the results of this study.
22
Syahriar, Ary, Putri Wulandari, Ahmad Husin Lubis, Retno Wigajatri, Danny M. Gandana, and Anwar Mujadin. "The Method of Lines Analysis of TE Mode Propagation in Silica based Optical Directional Couplers." Journal of Engineering and Technological Sciences 53, no. 3 (May 31, 2021): 210302. http://dx.doi.org/10.5614/j.eng.technol.sci.2021.53.3.2.
Abstract:
Optical directional couplers fabricated using planar light wave circuit (PLC) technology are versatile tools in integrated photonics devices. They have the advantages of small size, high consistency, ability for high volume production, and excellent possibility to be integrated with electronics circuits. Optical waveguide couplers are mainly utilized as power dividers, optical switches, and wavelength division multiplexers/de-multiplexers (WDM). A number of methods have been used to analyze directional couplers, such as coupled mode theory (CMT), the beam propagation method (BPM), the method of lines (MoL), finite-difference methods (FDM), and finite element methods (FEM). Among these numerical approaches, MoL is the simplest method to analyze mode propagation inside directional couplers because it has the advantages of very fast convergence and accurate solutions for one-dimensional structures. The objective of this study was to analyze the propagation of TE modes in optical directional couplers by using MoL. The parameters used, i.e. waveguide width, refractive index, and wavelength, were taken from the characteristics of silica-on-silicon directional couplers that were used in fabrication. MoL is considered a special finite-difference method, which discretizes a one- or two-dimensional wave equation in the transverse direction and uses an analytical solution for the propagation directions. Basically, MoL is a semi analytical numerical method with the advantages of numerical stability, computational efficiency, and calculation time reduction. Further, we explored the possibility of using directional couplers as optical switching devices.
23
Mei, Lidan, Nan Guo, Hongliang Zuo, Ling Li, and Guodong Li. "Influence of the Force Arm on the Flexural Performance of Prestressed Glulam Beams." Advances in Civil Engineering 2021 (January 15, 2021): 1–16. http://dx.doi.org/10.1155/2021/8831406.
Abstract:
In recent years, extensive attention has been drawn to prefabricated buildings, particularly wood construction. Glulam beams are the major supporting components of modern wood buildings. Since the force arm is the most critical indicator to evaluate the resistance moment of the glulam beam string structure, it is necessary to further study the influence of the force arm on the mechanical properties of the glulam beam string structure. We tested the flexural performance of 15 prestressed glulam beams, which were divided into two groups (A and B) to, respectively, research the influences of the string arm and the end arm on the bearing capacity, failure mode, stress distribution, and deformation performance of glulam beams. The results showed that when the height of the end arm remained constant and the string arm increased from 90 mm to 130 mm and 170 mm, the bearing capacity of the beam increased by 6.77% and 17.22%, respectively. Moreover, as the depth of the compression zone of the glued timber beam gradually increased, the failure mode of the beam changed from the brittle tension failure of the beam bottom to the ductile compression failure of the beam top. When the height of the string arm remained constant and the end arm increased from 10 mm to 30 mm and 50 mm, the bearing capacity of the beam increased by 4.27% and 8.13%, respectively. The beam had no significant change in the failure mode, while it could bear the stress more uniformly. Based on the experimental results and principles of equilibrium, moment equilibrium, and similar triangle, we calculated the ultimate bearing capacity of the glulam beam and proposed a design method for durable wood structures.
24
Alkhafaji, F. J., and A. F. Izzet. "Prestress Losses in Concrete Rafters with Openings." Engineering, Technology & Applied Science Research 10, no. 2 (April 4, 2020): 5512–19. http://dx.doi.org/10.48084/etasr.3390.
Abstract:
In this paper, experimental work was conducted to evaluate the losses in prestressing force of 13 (12 perforated and 1 solid) simply supported prestressed concrete rafters. All beams had the same dimensions and reinforcements. The tested beams were divided into four main groups and three additional subgroups were driven. These groups were classified according to size, number, and configuration of the openings, and the orientation of the posts (vertical or inclined). Regarding the prestress losses that have been affected by the cross-section properties, the provision of the codes is applicable only to prismatic solid beams, so non-prismatic or moreover perforated beams also need to be studied. This paper aims to propose a method based on the same code provisions but taking into consideration the cross-section variation along the beam length. The proposed method divides the overall length of the rafter into a number of assumed prismatic segments with heights measured at centers. Then, the overall prestress loss is found as the sum of these segments weighed by the ratios of the length of each beam segment to the overall length. The experimental results of the proposed method ranged from 84.749% to 95.607% denoting its validity.
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Jayakumar, Tammana, and Ellappan Rajendra Kumar. "Indian Test Blanket Module in ITER - Development of RAFM Steel and Fabrication Technology." Advances in Science and Technology 94 (October 2014): 1–11. http://dx.doi.org/10.4028/www.scientific.net/ast.94.1.
Abstract:
A detailed and comprehensive programme is undertaken in India to fabricate Indian Test Blanket Module (TBM) to be tested in ITER. Development of India-specific Reduced Activation Ferritic/Martensitic (RAFM) steel has been realized through melting and physical and mechanical properties characterization of several heats of 9Cr-RAFM steel with varying tungsten and tantalum contents. The RAFM steel having 1.4 wt. % tungsten and 0.06 wt. % tantalum is found to possess better combination of strength and toughness and is considered as India-specific RAFM steel. Different joining processes for fabrication of TBM have been assessed. Hot Isostatic Pressing (HIP) has been demonstrated to fabricate the first wall of TBM. To avoid channel collapse during HIPing, leachable ceramic cores were inserted in the channels. Electron Beam (EB) and Laser Welding processes are used for fabrication of breeder cassettes and hence, these welding procedures have been developed. Tungsten Inert Gas (TIG), Narrow Gap TIG (NG-TIG) and Laser Hybrid welding processes are being considered for integration of the various components such as first wall, back plate, bottom plate, breeder assembly and flow dividers into TBM. RAFM steel welding consumables have also been developed and qualified. Procedure for laser hybrid welding has also been developed. Necessary technologies for inspection and quality assurance of the fabricated TBM are also being developed. Use of ultrasonic C-Scan imaging to examine the bond integrity of the HIP joint has been demonstrated. Phased Array technique that would enable inspection of welds by longitudinal movement of the probe from an optimised lateral distance of the weld without the requirement of lateral movement has also been developed. The challenges in developing the India-specific RAFM steel and the fabrication and inspection technologies for fabrication of Indian TBM are presented.
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Al-Ansari, Mohammed Salem, and Muhammad Shekaib Afzal. "Simplified Irregular Beam Analysis and Design." Civil Engineering Journal 5, no. 7 (July 21, 2019): 1577–89. http://dx.doi.org/10.28991/cej-2019-03091354.
Abstract:
This paper presents simple method to estimate the strength design of reinforced concrete beam sections based on structural safety and reliability. Irregular beam shaped sections are commonly used nowadays in the construction industry. This study reveals the simplified method to analyze and design the different irregular shaped beam sections. In this study, the selected irregular beam shaped sections are divided mainly into three groups, beams with straight edges, beams with sloped edges and circular beams. Each group contains the most commonly used beam shaped sections in that category. Six beams sections (B-1 to B-6) are selected for group-1 whereas five beam sections (B-7 to B-11) and a circular beam section (B-12) are chosen for group 2 and 3 respectively. Flexural beam formulas for three groups of reinforced concrete beams are derived based on section geometry and ACI building code of design. This study also analyzed numerical examples for some of the sections in each group category using the proposed simplified method to determine the strength design of the irregular beams. The results obtained using simplified method for all of the three groups are compared with the finite element software (SAP v2000). The percentage difference of simplified method with the finite element software ranges within 5% to 10%. This makes the simplified method for irregular shaped beam sections quite promising.
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Huang, Dongzhou, and Mohsen Shahawy. "Analysis of Tensile Stresses in Transfer Zone of Prestressed Concrete U-Beams." Transportation Research Record: Journal of the Transportation Research Board 1928, no. 1 (January 2005): 134–41. http://dx.doi.org/10.1177/0361198105192800115.
Abstract:
Prestressed U-beam bridges compare favorably in cost and appearance to traditional concrete I-beam bridges. Consequently, U-beam bridges are gaining in popularity and usage, especially when aesthetic issues are deemed important. U-beam bridges first appeared in Florida in 2000; however, during construction, cracks developed in the webs of the U-beams. This paper presents results of an analysis of representative cracking of U-beams and proposes a practical method for the transfer zone stirrup design. For the purpose of the analysis, the U-beam is divided into a series of finite shell-plate elements, and the prestressing tendons are simulated as a number of concentrated forces. Two different mechanical models of the U-beams are developed on the basis of the stages of construction. Analytical results show that high tensile stresses occur in the end zone of the U-beam because of the prestressing tendons and that these tensile stress must be properly considered in bridge design. The research results are applicable to the design of prestressed U-beams and similar types of prestressed girders.
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Mohammed M. Rasheed, Dr, Mr Ali F. Atshan, and Mr Kamal Sh. Mahmoud. "Flexural Behavior of Steel Beam Strengthening by Prestressing Strands." International Journal of Engineering & Technology 7, no. 4.20 (November 28, 2018): 572. http://dx.doi.org/10.14419/ijet.v7i4.20.26421.
Abstract:
Seven simply supported steel beams were tested to explain the effect of strengthening by external prestressing strands. All of the beams have the same steel section, clear span length and the strengthening samples which implemented by two external prestressing strands. The tested beams are divided into two categories according to existing of external prestressing strands, the first category consists of one steel beam as a reference, while, the second group deals with steel beams strengthening by external prestressing strands and consists of six steel beams divided according to the eccentricity location of prestressing strand with jacking stress (815 MPa). From experimental results, it was found that the moment curvature curves behavior for the tested beams are stiffer and with less ductility than the reference beams and the ultimate moment capacity is increased with increasing the eccentricity location. While, the maximum radius of curvature at bottom flange decreases with increasing the eccentricity location as compare with the reference beam.
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Wang, Zhen Qing, Mu Qiao, Yu Lai Han, and Zhu Ju. "A Time-Variant Reliability Analysis of Reinforced Concrete Beams Working with Cracks under High Temperature." Applied Mechanics and Materials 197 (September 2012): 259–65. http://dx.doi.org/10.4028/www.scientific.net/amm.197.259.
Abstract:
The reliability of a reinforced concrete beam has been largely discounted when it under the action of fire. For a more accurate description of concrete beams’ reliability, the impact of cracks in reinforced concrete beams has been taking into account. Concrete is divided into elastic zone and plastic zone to calculate its strength. A simple and feasible time-variant model of reliability index of reinforced concrete beams under fire has been given. The effect of ISO834 temperature rising curve on the reliability index of concrete beam at different time has been analyzed. The reliability of a reinforced concrete beam under the ISO834 standard heating curve was assessed by first order second moment method.
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S. Abdullah, Wissam, and Hassan F. Hassan. "EFFICIENCY OF FLEXURAL STRENGTHENING OF REINFORCED CONCRETE BEAMS BY NEAR SURFACE MOUNTED CARBON FIBER REINFORCEMENT POLYMER RODS AND EXTERNALLY BONDED SHEETS." Journal of Engineering and Sustainable Development 25, Special (September 20, 2021): 4–100. http://dx.doi.org/10.31272/jeasd.conf.2.4.10.
Abstract:
This study investigated the flexural behavior of reinforcement concrete beam strengthened with different techniques. The purpose of this research to study the various techniques of strengthening and knowing the effect of each technique on the beam behavior .Ten simply supported beams tested in this study. The total length of the beams and clear span were 1800mm and 1650mm, respectively. The cross section was (180×250) mm. Tested beams were divided into two categories’ the first category consist of one beams and considered as reference, while the second category consist of nine beams divided into Two groups according to the Strengthening techniques such as near surface mounted (NSM) and external bonded reinforcement (EBR).The experimental results showed improvement in ultimate load capacity for strengthened beams ranging from (6 to 89%) for NSM and (31 to 96%) for EBR and reduction in deflection for strengthened beams ranging from (6 to 43%) as compared with reference beam. When the number and length of CFRP bars are increased, the number of cracks increase while the width of the cracks and the spacing decrease, and the same observation is made when the width of the CFRP sheet is increased. The experimental load capacities of strengthened beams were compared with the design provisions given by ACI440.2R-17 guideline for NSM and EBR technique and EC2 guideline for EBR technique, the average ratio (1.2 and 0.97) respectively ,which showed that reasonable and a good agreement for all strengthened beams.
31
Abdulla, Aziz, Reem Mahmoud, and Ammar Khazaal. "Toughness of Timber Beams Strengthened with Jute Fibers." Tikrit Journal of Engineering Sciences 27, no. 3 (December 25, 2020): 94–112. http://dx.doi.org/10.25130/tjes.27.3.11.
Abstract:
This research involves investigating the toughness behavior of timber beams strengthened by jute fibers with various forms of strengthening. Ten timber specimens with dimensions (70×100×1000) mm are divided into four groups and loaded under a third point loading. The experimental program was carried out to investigate shear and flexural strengthening effects on toughness, toughness indices, ultimate loads, and the mid-span deflection of the tested beams. One beam as a control beam (un-strengthened beam), four specimens are wrapped in U technique in single and double layers along the whole length of the beam in full and strips wrapping technique, three specimens are wrapped in full technique along the whole length of the beam in full and strips wrapping technique, three timber specimens wrapped in flexural strengthening technique with two, four, and six layers of jute fibers. The results show that jute fibers strengthening increases the toughness ratios of timber beams by about (175%-320%), (190%-401%), and (106%-240%) for U, full, and flexural strengthening techniques, respectively, at the ultimate loads compared with the control beam. Furthermore, it is found that the highest toughness ratio is when the beam is wrapped in full strengthening technique.
32
Hussein Abdallah, Muhammad, and Ali Hameed Aziz. "Torsional Strength Enhancement of Reinforced SCC Box Beams Using Internal Transverse Steel Bracing Technique." International Journal of Engineering & Technology 7, no. 4.20 (November 28, 2018): 299. http://dx.doi.org/10.14419/ijet.v7i4.20.25943.
Abstract:
An experimental investigation was conducted, in this paper, to evaluate the torsional strength enhancement of reinforced self-compacting concrete box beams using internal transverse steel bracing technique. Seven beam specimens have dimensions of (2100x300x300mm) for length; width and depth respectively, were poured and tested under pure torsion. Three variables were adopted in the present study; presence or absence of steel bracings, type of steel bracing (X-Type and XW-Type) and a number of steel bracing (1,3 and 5). Accordingly, the tested beams are divided into three groups (based on steel bracing type), the first group consists of one non-strengthened beam specimen (reference), the second group consists of three beams strengthened by X-Type steel bracing; while, the third group consists of three beams strengthened by XW-Type steel bracing. It was found that the ultimate torque moment increased by about (14.4%, 34.3% and 59.2%) for beam specimens containing one, three and five X-Type steel bracing, respectively, in comparison with the reference beam. While, the ultimate torque moment increased by about (21.9%, 41.8% and 71.6%), for beam specimens containing one, three and five XW-Type steel bracing, respectively, in comparison with the reference beam. The paper concludes that the contribution was enhanced using the adopted technique.
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Suryawanshi, Prof S. R. "An Experimental Study on Strengthening of Reinforced Concrete Flexural Members using Steel Wire Mesh." International Journal for Research in Applied Science and Engineering Technology 9, no. VII (July 20, 2021): 1706–10. http://dx.doi.org/10.22214/ijraset.2021.36442.
Abstract:
Reinforcing reinforced concrete (RC) beams with galvanized welded steel wire mesh is one of the latest technologies applied in retrofitting. For each sample, the experimental evaluation of 18 small reinforced concrete beam samples with a total length of 1200 mm was carried out to study the bending strength under static load conditions. Experimental testing has been carried out to the activated failure mode, with 11 reinforced samples, 4 integrally cast control beams and three original control beams. Based on the test variables, namely SWM characteristics and connection mechanism, the reinforced beams are divided into two groups A and B. This study also clarified the bending resistance, ductility, stiffness, crack width and deflection. According to the test results obtained, all reinforced beams are designed to fail ductilely. The first group of reinforced beams recovered to an average of 110% of the bearing capacity of the original control beam, while the second group of reinforced beams recovered to an average of 163%. Furthermore, it was found that the reinforcement beam functions in the same way as the general control beam and works as a unit. Therefore, the bottom line is that this reinforcement technology can be used confidently in real-life applications, especially in low- cost buildings.
34
Viet, N. V., W. Zaki, and Quan Wang. "Free vibration characteristics of sectioned unidirectional/bidirectional functionally graded material cantilever beams based on finite element analysis." Applied Mathematics and Mechanics 41, no. 12 (November 18, 2020): 1787–804. http://dx.doi.org/10.1007/s10483-020-2664-8.
Abstract:
AbstractAdvancements in manufacturing technology, including the rapid development of additive manufacturing (AM), allow the fabrication of complex functionally graded material (FGM) sectioned beams. Portions of these beams may be made from different materials with possibly different gradients of material properties. The present work proposes models to investigate the free vibration of FGM sectioned beams based on one-dimensional (1D) finite element analysis. For this purpose, a sample beam is divided into discrete elements, and the total energy stored in each element during vibration is computed by considering either Timoshenko or Euler-Bernoulli beam theories. Then, Hamilton’s principle is used to derive the equations of motion for the beam. The effects of material properties and dimensions of FGM sections on the beam’s natural frequencies and their corresponding mode shapes are then investigated based on a dynamic Timoshenko model (TM). The presented model is validated by comparison with three-dimensional (3D) finite element simulations of the first three mode shapes of the beam.
35
Петрин, А. Б. "Об эффекте Гуса-Хенхена при наличии возбуждения поверхностных волн в схеме Кречмана." Журнал технической физики 127, no. 10 (2019): 654. http://dx.doi.org/10.21883/os.2019.10.48372.43-19.
Abstract:
AbstractA theoretical method for investigating reflection of a finite-aperture plane light beam from a flat-layered structure in the Kretschmann scheme is considered. The developed theory is applied for investigating the Goos–Hänchen effect, which arises upon incidence of a linearly polarized light beam with the polarization vector lying in the plane of incidence ( p -polarized beam) and which is that, upon reflection, the incident beam is divided into two close beams of the same polarization. The accuracy of sensors based on this effect is discussed.
36
Duan, Shaowei, Wenzhao Zhou, Xinglong Liu, Jian Yuan, and Zhifeng Wang. "Experimental Study on the Bending Behavior of Steel-Wood Composite Beams." Advances in Civil Engineering 2021 (June 26, 2021): 1–12. http://dx.doi.org/10.1155/2021/1315849.
Abstract:
This paper proposes a steel-wood composite beam with H-shaped steel beam webs glued to the wood. As a new type of composite beam, it combines the advantages of low energy consumption of wood, high permeability, and less pollution and the advantages of light weight and high strength of steel, high degree of assembly, short construction period, and less construction waste generated. Carrying out research is of great significance to improve the mechanical properties of steel-wood composite beams and promote the development of steel-wood composite structures. In this paper, three hot-rolled H-beam-larch composite beams and one pure steel beam were tested for bending capacity. The composite beams are divided into two different combinations of A and B types. The two sides of the web are connected with larch wood by structural glue to form a composite beam. The type B composite beam is a larch wood glued on both sides of the H-shaped steel web and penetrates the bolts at the same time. Through the three-point monotonic static grading loading of the composite beam, the deflection change, failure phenomenon, and form of the specimen during the experiment were observed. Under the circumstances, the ultimate bearing capacity of the test piece was changed to study the combined effect of larch and hot-rolled H-shaped steel. The results show that the overall performance of the H-shaped steel-larch composite beam is good. Bonding wooden boards on both sides of the steel beam web can improve the bearing capacity, and the form of the member is more reasonable and effective; increasing the cross-sectional size of the H-beam in the steel-wood composite beam can further improve the bearing capacity of the composite beam; adding bolt anchorage on the basis of the structural glue used in the composite beam can further improve the bearing capacity of the composite beam. The superposition principle is used to simplify the calculation of the ultimate bearing capacity of H-shaped steel-larch composite beams. Comparing the calculation results with the test results, the data are in good agreement, which can provide a design reference for the practical application of such composite beams.
37
Jomaah, Muyasser M., and Diyaree J. Ghaidan. "Energy Absorption Capacity Of Layered Lightweight Reinforced Concrete Beams With Openings In Web." Civil Engineering Journal 5, no. 3 (March 19, 2019): 690. http://dx.doi.org/10.28991/cej-2019-03091279.
Abstract:
This research presents the flexural behavior on reinforced concrete beam with transverse web opening constructed from layered concrete. The layered concrete combining normal concrete and lightweight aggregate concrete (LWC) are depended in present study. In the experimental program, 13 models of normal and layered reinforced concrete beams are tested under the effect of four-point loads. All beams had the same overall geometrical dimensions and main longitudinal top and bottom with internal diagonal reinforcement provided around the openings. One of the beam specimen is tested as control beam and the other specimens are divided into three groups [G1, G2, and G3] to study the effects of the following variables: effect of presence of web openings, layered system, lightweight aggregate (partially volumetric replacement of normal aggregate by thermostone) on the ultimate load, cracking load, cracking pattern and energy absorption capacity. The existing of an opening in beam specimens reduced the flexural capacity of beams with a percentage depending on the size of opening and opening number. The test data obtained from the adopted layered technique of (NEW) and (LWC) have shown that for beams constructed from two layered concrete (LWC with thermostone in the web and bottom flange of I-beam section) ultimate load is decreased about (9.3%-48.8%). It has also, the beams constructed from three-layered of concrete (LWC with thermostone in the web of I-beam section), their ultimate load is decreased about (25.6%-58.1%). On the other hand, magnitude increased of energy absorption capacity are achieved by the decreased opening size, introducing the full size opening of dimension (100×1000) mm reduces the energy absorption capacity of the RC I-section beams at least 80% compared to solid beam while the beam with opening size (100×100) mm decrease up to 16%. In the case of the layered concrete beams specimen, the real influence of lightweight concrete (LWC) type in the layered reinforced concrete is observed significantly after increasing the length of opening more than 100 mm.
38
Apiputikul, Chatchalong, Kheamrutai Thamaphat, Monrudee Ranusawad, and Pichet Limsuwan. "Uncomplicated Setting Apparatus for Measurement of Fluid Flow Rate Using Laser Doppler Technique: Physics Teaching." Advanced Materials Research 770 (September 2013): 366–69. http://dx.doi.org/10.4028/www.scientific.net/amr.770.366.
Abstract:
Laser Doppler velocimetry (LDV) or laser Doppler anemometry (LDA) is the technique of using the Doppler shift in a laser beam to determine the fluid velocity. In this work, dual beam mode (two incident beams, single observation location) was selected to use. A cost effective and easy module for measurement of water flow rate was designed and constructed. A He-Ne laser with a wavelength of 632.8 nm was used as a light source. The laser was passed through a beam splitter and divided into two beams with identical intensity and coherence. Subsequently, the two laser beams travelled to a focusing lens with a focal length of 100 mm and focused on a center of water flow channel in quartz cuvette with a dimension of 1 × 1 × 5 cm3. The beam angle was set at 4.96°. When the seeding particles, bubbles and microorganism in water, were moving through the intersection point of two beams, the light was scattered. The scattered light was collected by photodetector connected to processing system. The frequency of scatterred light is shifted according to the Doppler shift relations due to effect of Rayleigh scattering. The water flow rate can be calculated from Doppler shift frequency.
39
Hashim, Hayder A., and Alaa H. Al-Zuhairi. "Effect of External Post-Tensioning Strengthening Technique on Flexural Capacity of Simple Supported Composite Castellated Beam." E3S Web of Conferences 318 (2021): 03006. http://dx.doi.org/10.1051/e3sconf/202131803006.
Abstract:
This research is carried out to study the effect of the external post-tensioning technique on the flexural capacity of simply supported composite castellated beam experimentally. In this research, seven composite castellated beams having the same dimensions and material properties were cast and tested up to failure by applied two concentrated loads at 700 mm from each end. Two external strands of 12.7 mm diameter were fixed at each side of the web of strengthening beams and located at depth 180 mm from top fiber of the section (dps) at each end of the beam. The strands have been tensioned by using a hydraulic jack with a constant stress of 100 MPa. This research aims to study the effect of the strengthening by different shapes of strand profiles of external post-tensioning techniques on the flexural capacity of the composite castellated beam. These beams were divided into three groups. Each group contained two composite castellated beams while 7th composite castellated beam kept without strengthening by external post-tensioning technique As control beam. The first group included two beams with straight strand profile of external Post-tensioning. The second group included two beams with a triangular strand profile of external post-tensioning. The third group included two beams with a trapezoidal strand profile of external post-tensioning. All composite castellated beams were simply supported, and all of them were fully shear connections between the concrete slab and steel girder. All beams included the 16 castellated openings and were stiffened by six stiffener plates welded on the web of castellated beams. Three stiffener plates are welded on each side of the web. Two of these stiffener plates welded at the middle of the beam, and four of them welded at locations under the loads. The experimental results of this research were increasing 5.43% in load capacity of an average of the straight profile of composite castellated beams, increasing 18.92% in load capacity of an average of triangular profile composite castellated beams, and increasing 20.71% in load capacity of the trapezoidal profile of composite castellated beams. All the above results were compared with control beams.
40
Purnamaningsih, Retno Wigajatri, Nji Raden Poespawati, Tomy Abuzairi, and Elhadj Dogheche. "An Optical Power Divider Based on Mode Coupling Using GaN/Al2O3 for Underwater Communication †." Photonics 6, no. 2 (June 3, 2019): 63. http://dx.doi.org/10.3390/photonics6020063.
Abstract:
This paper details the design of a 1 × 8 optical power divider, using a gallium nitride (GaN) semiconductor on sapphire, which can be applied to underwater optical wireless communication. The design consists of nine parallel rectangular waveguides which are based on mode coupling phenomena. Analysis of the design was performed using the beam propagation method (BPM). The optimization was conducted using the 3D finite difference (FD)-BPM method with an optical signal input at the wavelength required for maritime application of λ = 0.45 µm. The signal was injected into the central waveguide. The results showed that at a propagation length of 1480 µm the optical power is divided into eight output beams with an excess loss of 0.46 dB and imbalance of 0.51 dB. The proposed design can be further developed and applied in future underwater communication technology.
41
H. Abbas, Oday, and Hesham A.Numan. "ENHANCING OF FLEXURAL STRENGTH OF WEB OPENING REINFORCED GEOPOLYMER BEAMS BY USING FRP STRIPS." Journal of Engineering and Sustainable Development 25, Special (September 20, 2021): 4–135. http://dx.doi.org/10.31272/jeasd.conf.2.4.13.
Abstract:
This study is devoted to inspect the flexural behavior of Geopolymer reinforced concrete beams with “large” web transverse opening and strengthened by three kinds of Fiber Reinforced Polymer materials. The implemented experimental program comprised casting eight beams under static and “one stage” repeated load, two of these are normal concrete beams and the others are Geopolymer beams. These beams are divided into two groups, the first comprised four beams of solid and beams “with transvers web opening” under static load for normal and Geopolymer concrete beams. The second group are of four Geopolymer beams that one of them is “un strengthened and having transvers web opening” while the others are also have transvers web opening but strengthened by different kinds of Fiber Reinforced Polymer materials sheets that installed vertically aligned and accompanied with the 90mm diameter large circular web opening. The strengthening materials included are Carbon Fiber Reinforced Polymer, Glass fiber Reinforced Polymer and Hybrid (one layer of Glass + one layer of Carbon) reinforced polymer sheets. The results showed that for the ultimate load capacity was decreased by 9.96% for holed normal concrete beam if compared with solid normal concrete solid beam while such capacity was decreased 2.25% and 11.89% for solid and holed Geopolymer beams respectively. In addition to that, the maximum load capacity is also decreased by 8.16%, 10.20% and 12.25% for Glass, Carbon and Hybrid fiber reinforced polymer strengthened beams if compared with reference beams “holed un strengthened beam” subjected to cyclic load.
42
Spagnolo JR, L. A., E. S. Sánchez Filho, and M. S. L. Velasco. "RC T beams strengthened to shear with carbon fiber composites." Revista IBRACON de Estruturas e Materiais 6, no. 1 (February 2013): 1–12. http://dx.doi.org/10.1590/s1983-41952013000100002.
Abstract:
This paper presents the experimental data of the behavior of reinforced concrete beams strengthened to shear with carbon fiber composites. The tests were composed of eight T beams, b w=15 cm, h=40 cm, flange width 40 cm, flange height 8 cm, and length 300 cm, divided into two series with the same longitudinal steel reinforcement and a reference beam without strengthening in each series. The beams had two types of arrangement of internal steel stirrups. The test variables were the internal and external geometric ratio of the transverse reinforcement and the mechanical ratio of carbon fiber composites stirrups. All the beams were loaded at two points. The strengthened beams were submitted to a preloading and the strengthening was applied to the cracked beam. All the beams were designed in order to guarantee shear failure, and the ultimate load of the strengthened beams was 36% to 54% greater than the reference beams. The Cracking Sliding Model applied to the strengthened beams was evaluated and showed good agreement with the experimental results.
43
AL-Farttoosi, Hayder, Oday Abdulrazzaq, and Haleem Hussain. "Shear Behavior of Two-Layer Beams Made of Normal and Lightweight Concrete Layers." Basrah journal for engineering science 22, no. 1 (April 24, 2022): 115–28. http://dx.doi.org/10.33971/bjes.22.1.14.
Abstract:
This study investigates the shear strength behavior of two-layer reinforced concrete beams consisting of two different types of concrete. One of the layers made of lightweight concrete (LWC) and the other was normal weight concrete (NWC). A total of 16 shear deficient reinforced concrete beams were fabricated and cast with NWC, LWC, and two-layer beam of both material with different configuration. All the beams were tested under four-point loading after 28 days. The variables of the experimental program include the ratio of thickness of the lightweight concrete layer to the overall depth of beam (hLW/h), and concrete compressive strength. Experimental results which include load-deflection response curves along with failure modes for NWC, LWC and two-layer beams. The results showed that all beams failed in a similar mode, due to diagonal tension shear crack. Based on the experimental results it can be also concluded that the shear load is governed by compressive strength of lower layer of the concrete when the shear span to overall depth (a/h) of the beams is 2.75 or more. While for the a/h 2.375 and 2.00 the two-layer beam has a significant reduction in the shear capacity compared to the NWC beams and increasing compared to LWC beam. The ratio of experimental shear stress divided by the root square of concrete compressive strength (vexp⁄√(f_c^' )), which demonstrates the diagonally cracked concrete's ability to transfer strain and shear was maintained for all configurations greater than 0.17, which is the minimal value recommended by ACI318-19.
44
Said, Abdul Muttalib I., and Qais H. Al-Shemmari. "Behavior of Strengthened RC Beams with CFRP Sheets under Combined Bending and Torsion." Key Engineering Materials 857 (August 2020): 109–19. http://dx.doi.org/10.4028/www.scientific.net/kem.857.109.
Abstract:
The experimental investigations were carried out to study the behavior of reinforced concrete beams strengthened by CFRP sheets under different loading conditions (pure bending, combined bending and torsion and pure torsion). The experimental work included testing twenty RC beams of the rectangular cross-section of dimensions of 160×240 mm and of 2600 mm length with an area of the ordinary reinforcement being kept constant for all beams. Two parameters were taken into consideration (Twisting to bending moment ratio (T/M) and CFRP strengthening pattern). The tested beams are divided into five groups. Each group consists of four beams; the first beam is without CFRP strengthening, the other three are strengthened with CFRP sheets of different arrangements (U-stirrups, U-stirrups and longitudinal CFRP sheets in the bottom and Full U- stirrups wrapping). Each beam is loaded to a different loading conditions (pure bending, T/M = 0.5, T/M = 1.0, T/M = 2.0 and pure torsion). The CFRP sheets were attached externally to the beam. Test results were analyzed based on the influence of CFRP on the ultimate load, vertical mid-span deflection and failure modes. In the experimental work, it was found that all strengthening patterns of CFRP sheets exhibited a significant increase in ultimate strength. This increase reached up to 78.9% for tested beams, when the beam strengthened in the form of full U- stirrups wrapping pattern for T/M = 0.5. In this study, it is observed that the use of external CFRP sheets attached to the tension sides of beams (U-stirrups and longitudinal CFRP in the bottom) could enhance the ultimate load capacity by 32.7% over the capacity of the unstrengthen control beam for T/M = 1.0.
45
Badawy, Amr H., M. S. El-Feky, Ahmed Hassan, Hala El-kady, and L. M. Abd-El Hafez. "Flexural Behavior of Unbounded Pre-stressed Beams Modified With Carbon Nanotubes under Elevated Temperature." Civil Engineering Journal 5, no. 4 (April 28, 2019): 856–70. http://dx.doi.org/10.28991/cej-2019-03091294.
Abstract:
Since fire is one of the common reasons for rehabilitation and reconstructions during the service life of a building, it is necessary to assess the elements structural and technical conditions. The objective of the present paper is to investigate the flexural behavior in bending for unbounded full pre-stressed beams with and without the incorporation of carbon nanotubes (CNTs) under the exposure to elevated temperature in comparison with non-pre-stressed beams. The test Method was divided into two major stages where the principal stage’s goal was considering the flexural behavior of fully and non-prestressed concrete beams containing CNT of 0 and 0.04% as cement replacement at ambient temperature. In the second stage, a typical group of beams was prepared and the flexural behavior was explored under the exposure to temperature of 400ºC, for 120 minutes. The major findings upon monitoring the failure mechanisms, ultimate load capacity, and deflection at critical sections, was that the CNT had shown a significant impact on the behavior and extreme resistance of fully and non-prestressed normal concrete. With CNT beams also exhibited higher imperviousness to high-temperature than that of the normal beams. Finally the significant Improvement was that the ultimate load of the non-pre-stressed beam with the presence of the CNT at the lower 50mm in the tension zone showed a gain of 13%, while the ultimate load of the fully pre-stressed beam with the presence of the CNT at the lower 50mm in the tension zone showed a gain of 21% as compared to the same beam without CNT, respectively. For the non-pre-stressed beams, the load capacity of the beam with CNT after exposure had a similar load capacity as the beam without CNT before exposure to high temperature.
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Turki, Abbas Yahya, and Mahdi Hameed Al-Farttoosi. "Flexural Strength of Damaged RC Beams Repaired with Carbon Fiber-Reinforced Polymer (CFRP) Using Different Techniques." Fibers 11, no. 7 (July 14, 2023): 61. http://dx.doi.org/10.3390/fib11070061.
Abstract:
In this study, an experimental program was developed to investigate the flexural behavior of pre-damaged reinforced concrete (RC) beams that had been repaired and strengthened using carbon fiber-reinforced polymer (CFRP) laminates under a monotonic load. Two techniques were used: externally bonded reinforcement (EBR) and near-surface-mounted (NSM) reinforcement, to repair and strengthen the tested beams. The experimental program involved casting and testing nine simply supported RC rectangular beams; one beam was considered as the reference beam and did not undergo additional strengthening, and the remaining beams were strengthened using CFRP laminates. These eight beams were divided into two main groups for the purposes of strengthening: beams for which the EBR technique was used, and beams for which the NSM technique was used. The primary variables observed in the EBR and NSM groups included four damage percentages obtained according to the preload (20, 40, 60, and 80%) from the ultimate load carried by the reference beam. The experimental results show that decreasing the damage percentage leads to an increase in ultimate strength from about 3.6% to 17.2% for the beams repaired using the EBR technique and from 27.6% to 57% for the beams repaired using the NSM technique; additionally, the NSM method was more effective than the EBR method in terms of the flexural strength and mode of failure. However, using CFRP laminates enhances the flexure capacity of strengthened RC beams.
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Gnedy, Magdy, Mohamed Helmy, and Mohamed Hatem. "Investigation of Tensile Lap-Splice Hybrid Steel Bars Used in RC Beams under Flexure." Key Engineering Materials 921 (May 30, 2022): 283–91. http://dx.doi.org/10.4028/p-g198vn.
Abstract:
During the last two decades, fiber reinforced polymer (FRP) reinforcing bars for concrete structure has been extensively investigated and a number of FRP bars are commercially available. Using glass fibers and unsaturated polyester resins, steel fiber reinforced polymer composite bars (SFCB) were manufactured and introduced to the commercial market. Lap splice of such bars must be thoroughly investigated. Limitations of steel reinforcement lengths available from the plant (generally 12 m), causing the construction actors to splice the reinforcement. The simplest and easiest way is to make a lap splice, which made overlap by a certain length is called the developing length of lap splice bar. The main objective of this research using the concept of material hybridization, is to investigate the effect of bar diameter after adding fibers & code equation coefficients for best efficient developing length for tensile lap splice in beams under flexure. Nine RC beams were casted with dimensions of (25*40*420) cms and concrete strength of 300 kg/cm2. Beams were divided into three groups according to the fiber thickness added to 10 mms’ steel bars. First group contained three beams reinforced with hybrid bars of diameter 12 mms, 10mms steel coated with 2mms fiber. Beam one casted using bars with lap splice of 1.3*50φ, beam two casted using bars with lap splice of 1.3*55 φ & beam three casted using bars with lap splice of 1.3*60 φ. Second group contained three beams reinforced with hybrid bars of diameter 14 mms, 10mms steel coated with 4 mms fiber, beam one casted using bars with lap splice of 50φ, beam two casted using bars with lap splice of 55 φ & beam three casted using bars with lap splice of 60 φ. Third group contained three beams reinforced with hybrid bars of diameter 16 mms, 10mms steel coated with 6 mms fiber , beam one casted using bars with lap splice of1.3* 50φ , beam two casted using bars with lap splice of 1.3*55 φ & beam three casted using bars with lap splice of 1.3*60 φ . Beams were tested under four-point load to create a region of pure flexure stress. Load –deflection curves are presented along with percentage differences. Finally, conclusions were drawn and presented in this paper.
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Khodabandehlo, Ahmadreza, and Mohamad Taghi Kazemi. "Seismic Behavior and Study of RCS Composite Frame Composed of Steel Beams and Strong Concrete Column." Civil and Environmental Engineering 15, no. 2 (December 1, 2019): 142–53. http://dx.doi.org/10.2478/cee-2019-0018.
Abstract:
AbstractWith spreading of population and increasing of instruction, and also because of limited resources and materials, the demand for using novel materials in building industry has increased. The reinforced concrete columns and steel beams are used in structures with composite moment frame (RCS). Use of compression strength in proportion with concrete and bending strength of steel beam has bestowed these structures less weight than that of concrete structures and made it easier to access the measure of strong column - weak beam especially within long span in these structures. The most important part of these structures is connection of steel beam with the reinforced concrete column. These connections are divided into two general groups of connection with bracing beam and with bracing column from the joint. This paper aims to study the seismic behavior and parameters of RCS composite frame composed of steel beams and strong concrete column. The finite element method was analyzed by ABAQUS software and data analyzed by Excel.
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El Battawy, Osama Megahed, Khaled Farouk El Kashif, and Hany Ahmed Abdalla. "Experimentally Comparative Study on Different Strengthening Methods of Reinforced Concrete Deep Beams." Civil Engineering Journal 5, no. 9 (September 23, 2019): 1997–2006. http://dx.doi.org/10.28991/cej-2019-03091388.
Abstract:
The aim of this study is to investigate the effect of strengthening reinforced concrete deep beams. An experimental study was done using six reinforced concrete deep beams have the same dimensions of 1150×800×150 mm, and subjected to mid-span concentrated load up to failure. Beams were different in the type, Location of strengthening and the ratio of reinforcement. Beams were divided into three groups. The first group included beams strengthened internally by single strut and either vertical or horizontal additional reinforcement. The second group included beams strengthened using double embedded strut or using CFRP as external strengthening. The third group included one beam strengthened using inclined stirrups. One of the specimens was tested without any strengthening and one specimen was strengthened by external CFRP sheets for comparison purposes the results of the experimental study shown remarkable improvement for using each type of strengthening. Results shown that using the mechanism of increasing stirrups by double rate and using single strut reinforcing is the optimum choice. This is due to the fact that this type of strengthening provides significant increase in the beam capacity in additional to the enhanced behavior of the beam. By this study comparison between each type of strengthening was done and the optimum type to be used in accordance with parameters of gained load capacity of tested deep beams.
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Chen, Xueyu, Haijian Zou, Mingyang Su, Linwei Tang, Chaofeng Wang, Shuqing Chen, Chenliang Su, and Ying Li. "All-Dielectric Metasurface-Based Beam Splitter with Arbitrary Splitting Ratio." Nanomaterials 11, no. 5 (April 28, 2021): 1137. http://dx.doi.org/10.3390/nano11051137.
Abstract:
The development of optical systems is heading to multi-branch circuit design and miniaturization. A beam splitter is a common device for dividing an incident beam into two separate beams. Conventional beam splitters are constructed using coated prisms or glass plate. Their bulky size, right-angled output direction, and fixed splitting ratio greatly limit the design of optical arrangement and also hinder the system integration. Here, an all-dielectric metasurface composed of symmetric nano-rings as a beam splitter are designed by Finite-Difference Time-Domain method. By changing the inner and outer radiuses of the nano-rings, the wavefront phase of the emergence beam can be adjusted to form a phase gradient, and the incident beam of arbitrary polarization is divided into two beams according to the designed transmittance and angle. The initial phase of the emergence beam can be changed by adjusting the refractive index of the substrate or adding the silicon film to the substrate, and the splitting ratio can be adjusted from 0.5:1 to 1:1. The simulation demonstrates that the metasurface-based beam splitter is independent of polarization and the power efficiency is over 92% with a compact area of 33.6 μm × 33.6 μm. This compact metasurface-based beam splitter has promising potential for enabling new types of compact optical systems and advancing metasurface-based functional integrated photonic applications.