Beam Test Results Research Articles

Static and Dynamic Characteristics of Steel‐Concrete Composite Track Beam of Straddle Monorail with Cluster‐Distributed Studs

Because the transportation mode of straddle monorail is that the vehicle runs in the state of hugging the track, its track beam is usually a narrow‐high cross section. In order to study the static and dynamic characteristics and variation law of prefabricated steel‐concrete composite beam of straddle monorail with “cluster‐distributed studs” (CDS), a full bridge test model with a scale ratio of 1 : 3 was made. Relevant theoretical analysis, numerical simulation, and model test were carried out, and the data of structural frequency and damping, load‐deflection curve, and section height‐strain curve were obtained. The results show the following: (1) the equivalent vertical bending stiffness of the composite track beam of straddle monorail is nonlinear. The greater the load, the faster the stiffness decrease, and the greater the difference with the theory of composite beam with “uniformly distributed studs” (UDS). (2) At the same section, the deformation of steel beam and concrete slab is not coordinated along the height direction. The strain value of concrete slab is significantly larger than that of the upper edge of steel beam, so it is difficult to apply the plane‐section assumption. (3) Compared with all the measured results of the track beam test, the results of the detailed shell‐solid FEM model based on the load‐slip curve obtained by push‐out test are close to them, and the maximum error is 11.4% difference in stress. (4) Compared with the results obtained by the theoretical formula of the UDS, the results obtained by the theoretical formulas of the CDS based on a “correction coefficient of vertical bending stiffness” proposed in this paper show less deviation comparing to the measured results of the track beam test and are more resilient. When the correction coefficient is 0.9, the maximum error is 23.8% difference in stress. In the design of this kind of structure, the proposed formula can be used for early scheme comparison and later size optimization. Compared with the detailed shell‐solid FEM model, the proposed formula significantly reduces the design workload.

Experimental and numerical study on Mode I and Mode II interfacial fracture toughness of co-cured steel-CFRP hybrid composites

Interfacial fracture toughness of co-cured steel-carbon fiber reinforced plastic (CFRP) hybrid composites were investigated in this paper. To illustrate the effect of the interlayer on the fracture toughness, steel-CFRP hybrid composites were prepared by different manufacturing processes based on steel surface treatment (abrasion or grit blasting) and adhesive-bonding process. The experimental results of double cantilever beam (DCB) tests and end notched flexure (ENF) tests demonstrate that, the Mode I and Mode II interfacial fracture toughness of the hybrid composites can be improved by using a grit blasting surface treatment on steel and introducing an adhesive layer at the steel/CFRP interface. The hybrid composites mainly show fiber/epoxy interfacial failure of CFRP under Mode I loading conditions, while it mostly exhibits adhesive failure of steel/CFRP interface under Mode II loading condition. Moreover, the interfacial tensile strengths of steel-CFRP hybrid composites are predicted by finite element analysis, and both experimental and numerical results confirm the improvement of interfacial fracture toughness.

Beam test results of silicon sensor module prototypes for the Phase-2 Upgrade of the CMS Outer Tracker

The start of the High-Luminosity LHC (HL-LHC) in 2027 requires upgrades to the Compact Muon Solenoid (CMS) experiment. In the scope of the upgrade program the complete silicon tracking detector will be replaced. The new CMS Tracker will be equipped with silicon pixel detectors in the inner layers closest to the interaction point and silicon strip detectors in the outer layers. The new CMS Outer Tracker will consist of two different kinds of detector modules called PS and 2S modules. Each module will be made of two parallel silicon sensors (a macro-pixel sensor and a strip sensor for the PS modules and two strip sensors for the 2S modules). Combining the hit information of both sensor layers, it is possible to estimate the transverse momentum of particles in the magnetic field of 3.8 T at the full bunch-crossing rate of 40 MHz directly on the module. This information will be used as an input for the first trigger stage of CMS. It is necessary to validate the Outer Tracker module functionality before installing the modules in the CMS experiment. Besides laboratory-based tests several 2S module prototypes have been studied at test beam facilities at CERN, DESY and FNAL. This article concentrates on the beam tests at DESY during which the functionality of the module concept was investigated using the full final readout chain for the first time. Additionally the performance of a 2S module assembled with irradiated sensors was studied. By choosing an irradiation fluence expected for 2S modules at the end of HL-LHC operation, it was possible to investigate the particle detection efficiency and study the trigger capabilities of the module at the beginning and end of the runtime of the CMS experiment.

Behavioural mechanism of SBR, LDPE, and SBS modified bituminous mixtures

ABSTRACT Increased heavy-vehicle traffic, higher traffic volumes, and temperature changes lead to distresses such as stripping, rutting, fatigue cracks in asphalt pavements, increasing the cost of road maintenance. Therefore, it is inevitable that the properties of bitumen and asphalt mixtures must be improved. Polymer modification is one of the methods to improve bitumen properties. In the present paper, styrene butadiene styrene (SBS), styrene-butadiene rubber (SBR), and low-density polyethylene (LDPE), along with Sasobit wax, were used to modify the bitumen. For that purpose, we used tests, including conventional bitumen tests and linear amplitude sweep (LAS) tests. The results of the present study showed that the polymer mentioned above improves the rutting index of the base bitumen. Based on the bending beam test results, polymer additives and Sasobit have no positive effect on the low-temperature performance of the base bitumen. The LAS test results were used to compare PMBs’ fatigue performance, and it was evident that SBR had the most significant effect on increasing the fatigue life of the base bitumen. In the meantime, Sasobit increases the fatigue life of PMBs at high strain levels.

Effects of curcumin on neurobehavior and oxidative stress in hippocampus of rats exposed to manganese

Objective: To establish the animal model of subchronic manganism, and to explore the effect of manganese on neurofunction of rats and the protective effect of curcumin on neurotoxicity of manganism rats. Methods: From July to December 2019, 80 SPF male SD rats were divided into 8 groups according to body weight by random number table method, which were blank control group, low, middle and high dose manganese exposure group, low, middle and high dose curcumin antagonistic group and curcumin group, with 10 rats in each group. The low, middle and high dose manganese groups were given intraperitoneal injection of 5 mg/kg, 10 mg/kg and 15 mg/kg MnCl(2)·4H(2)O respectively. The low, middle and high dose curcumin antagonistic groups were given 100 mg/kg, 200 mg/kg and 400 mg/kg curcumin orally along with 15 mg/kg MnCl(2)·4H(2)O intraperitoneal injection. Curcumin group was given 400 mg/kg curcumin orally. The rats were exposed to 5 days a week, once a day for 16 weeks. After exposure, neurobehavioral tests (balance beam test, Morris water maze, passive avoidance test) were carried out in each group. Hippocampus tissues were taken for pathological examination and oxidative stress indexes were detected. Results: The balance beam test results showed that, compared with the blank control group, the scores of balance beam of the rats in the middle and high dose manganese exposure groups increased (P<0.05) . Compared with the high dose manganese exposure group, the balance beam scores of the low, middle and high dose curcumin antagonistic groups were decreased (P<0.05) .The results of Morris water maze showed that, compared with the blank control group, the escape latency of middle and high dose manganese exposure groups was prolonged from the third day (P<0.05) , and the average number of crossing the platform area of each manganese exposure group was decreased (P<0.05) .Compared with the high dose manganese exposure group, the escape latency of the middle and high dose curcumin antagonistic groups was shortened (P<0.05) , and the average number of crossing the original platform was increased (P<0.05) . The results of passive avoidance test show that, compared with the blank control group, the number of errors were increased in middle and high dose manganese exposure groups (P<0.05) . Compared with the high dose manganese exposure group, the number of errors in the passive avoidance test in the middle and high dose curcumin antagonistic groups were decreased (P<0.05) . Pathological examination showed that the rats treated with manganses had different degrees of degeneration and necrosis of nerve cells, and the structure of nerve cells was blurred and the number of nerve cells decreased. The above phenomena were improved after curcumin antagonism. The results of oxidative stress index showed that, compared with blank control group, the activity of superoxide dismutase (SOD) decreased and the content of malondialdehyde (MDA) increased in the hippocampus of rats exposed to middle and high dose of manganese (P<0.05) . Compared with the high dose manganese exposure group, the SOD activity increased and the MDA content decreased in the middle and high dose antagonist group (P<0.05) . Conclusion: Subchronic manganese exposure can reduce the balance function, learning and memory ability of rats, and damage the hippocampal nerve cells in oxidative stress state. Curcumin can improve the balance function and learning and memory ability of rats with manganese poisoning, improve the hippocampal nerve damage caused by manganese exposure, and has a certain protective effect on manganese induced neurotoxicity.

Experimental setup for beams with adjustable rotational stiffness: An educational perspective

AbstractIn structural analysis, the rotations of beams' supports are considered either completely fixed or completely free. Therefore, supports are idealized as fixed, pinned (hinged), or roller. In real structures, regarding rotation, the support behavior is neither fully rigid nor completely free and shows a semi‐rigid behavior in most cases. In this study, an educational test setup was created for a beam with semi‐rigid supports to examine the effect of semi‐rigid support on structural behavior. In this experimental setup, support conditions with different rotational stiffness can be obtained from pinned support to fixed support, which can be easily changed between the pinned and the fixed support. The physical equivalent of the rotational stiffness concept is shown in an easy and understandable way with the theoretical equations. A simulation tool based on the derived analytical equation is also developed using Mathematica Software. The simulation tool provides the users with a way to visualize the deformation of the system. The results of beam tests with different support conditions were compared with the results of the simulation, and the effects of semi‐rigid support on the beam behavior were shown. The results revealed that the semi‐rigid supported beam assembly created can also be used to examine the behavior of frame beams under vertical load. These simple novel experimental setup and simulation tools provided are convenient and useful approaches to demonstrate the structural concepts, including the semi‐rigid support and behavior of beams in a frame structure.

Experimental study on flexural behavior of the BFRC-concrete composite beams

Three specimens of composite beams were tested under a four-points bending test to study the effect of BFRC height on the flexural behavior of the composite beam. The numerical software MATLAB was used to numerically study the bending moment-curvature (M-φ) relationship of the composite beams. The finite element software (ABAQUS) was used to simulate the flexural behavior of the composite beams, and the parameter analysis is carried out to study the effect of strength and height of BFRC, strength and ratio of steel reinforcement on the flexural performance of BFRC-concrete composite beams. The study results show that the flexural capacity of the composite beam is higher than that of the normal concrete beam. With the increase of the height of the BFRC, the flexural capacity increases, and the bottom crack propagation is significantly inhibited. The BFRC height has a negligible effect on the ductility of the composite beam. The results illustrate the assumption of the plane section is valid, and the bonding behavior between steel bar and BFRC as well as the co-working between BFRC and ordinary concrete are perfect. Based on the experimental results, formulae are developed for predicting the cracking, yield, and ultimate moment bearing capacity of the composite beam, and a simplified formula is also developed for predicting the ultimate bearing capacity of composite beam with a balanced reinforcement ratio. The prediction results are consistent well with the test results, and the simulation results exhibit a good agreement with the test results of composite beams.

On the evaluation of FPGA radiation benchmarks

This paper presents a benchmarking methodology to analyse the failure mechanisms of FPGAs under radiation, using comparative results on the radiation sensitivity of parallel multipliers with different implementations. Atmospheric neutron beam test results of Artix7, Spartan7 and IGLOO2 FPGAs are presented and validated against fault injection campaigns.

Feasibility assessment of bulk density property of carbon nano tube as a viable alternative to reinforcement steel in construction projects

Carbon nanotubes are fibrous and porous materials prepared using standard test procedures of concrete. This research paper investigates the effect of three different bulk densities of multi-walled carbon nanotubes (MWCNTs) used in concrete. The results show that the specimens with lower range bulk density (0.04–0.06 g/cc) have better dispersion, mechanical and durability properties than higher range bulk densities. It is noteworthy that, during flexural beam test, MWCNTs are placed only at the bottom one-third of the specimen below the neutral axis, where most of the tensile region exists, without any joints. Flexural beam test results show that higher strength up to 9.62 MPa is obtained. The compression test reveals that higher strength possibly due to the reduced surface area of addition of bigger size coarse aggregates. A comparative of cost analysis with conventional steel rods is presented. Improvement in the ratio of flexural strength to compressive strength in respect of concrete is not as substantial as in mortar.

Design and verification of the HXI collimator on the ASO-S mission

A space-borne hard X-ray collimator, comprising 91 pairs of grids, has been developed for the Hard X-ray Imager (HXI). The HXI is one of the three scientific instruments onboard the first Chinese solar mission: the Advanced Space-based Solar Observatory (ASO-S). The HXI collimator (HXI-C) is a spatial modulation X-ray telescope designed to observe hard X-rays emitted by energetic electrons in solar flares. This paper presents the detailed design of the HXI-C for the qualification model that will be inherited by the flight model. Series tests on the HXI-C qualification model are reported to verify the ability of the HXI-C to survive the launch and to operate normally in on-orbit environments. Furthermore, results of the X-ray beam test for the HXI-C are presented to indirectly identify the working performance of the HXI-C.

Hi’Beam-A: A Pixelated Beam Monitor for the Accelerator of a Heavy-Ion Therapy Facility

In this article, a noninterceptive and high-accuracy beam position monitor, named Hi'Beam-A, has been designed for the accelerator of a heavy-ion therapy facility. The Hi'Beam-A consists of the detector subsystem and the readout subsystem. In the detector subsystem, the microchannel plate multiplies the ionized charge in the high vacuum chamber, and the novel Topmetal silicon pixel sensor directly collects the charge. The readout subsystem processes the data and calculates the beam position. Beam test results show that the Hi'Beam-A reaches an accuracy of 5 μm. This article will present the design, characterization, and beam test of Hi'Beam-A.

Parametric responses of carbon-epoxy composite with delamination using cohesive gap element

This paper focuses on the various parametric responses of the delaminated carbon-epoxy composite beam using a gap element. The analysis is based on the cohesive zone modelling approach, and it is implemented using the finite element software ANSYS APDL. In the study, a zero-thickness cohesive gap element that varies the cohesive stresses with the interfacial opening displacement along the localized fracture process zone is used. The available published results of the double cantilever beam test are used to validate the results obtained from the current analysis. The effects of fracture length, number of layers, angle of plies and thickness on delamination of a composite cantilever beam with edge pull is considered in this paper. The results show that the separation between the composite plies is proportional to the stiffness of the cohesive element, and an increase in the number of layers depicts a transition from anisotropy to orthotropy. Under mode I delamination, composite plies with 450 fibre angles exhibits increased torsional stiffness and global resistance. Also, a comparison between thin and thick laminates demonstrate that a laminate of 5 mm thick dissipates about 85% more energy than a composite laminate of 50 mm thick.

Numerical study on design rules for minimum degree of shear connection in propped steel–concrete composite beams

This manuscript presents a numerical study on simply supported propped composite beams with ductile shear connectors subjected to uniformly distributed load. The aim is to assess the performance of the revised rules for the minimum degree of shear connection (CEN/TC250/SC4.T3) with respect to the occurring slip. First, a non-linear 3D finite element model was developed through the software ABAQUS 2017 and validated against analytical and full-scale beam test results. Then, 91 configurations were analysed for different degrees of shear connection η = 0.2, 0.4, 0.6, 0.8 and 1.0. The span ranges from 6 to 25 m while the geometrical and mechanical properties varied within their typical field of applicability. According to both current and revised rules, 16 configurations with relatively deep beam and “weak” concrete slab exhibited allowable slip values smax significantly higher than 6 mm. Therefore, the authors proposed a reduction of the maximum degree of utilization to these special cases. If the proposed reduction is included in the revised rules, none of the considered cases exhibit a slip smax higher than 8 mm while few cases have smax between 6 and 8 mm. For the ease of use, a design proposal is reformulated as a conditional reduction of the plastic bending resistance of the composite section.

Correlation between results obtained from four-point bending tests (4PBT) and double punch tests (DPT) in concrete reinforced with hooked-end steel fibers

Most building codes prescribe the performance of steel fiber reinforced concrete (SFRC) from beam test results and, therefore, correlation models are required to estimate beam performance from more simplified tests such as double punch test (DPT). DPT provides advantages in terms of specimen size, equipment and simplified testing procedures. It also causes less variations in results, as compared to other methodologies of indirect tensile tests. The objective of this study is to propose correlations between SFRC’s strength and toughness test results measured from 4PBT in beams and DPT in cylinders. The variables of the experimental program were the dosage and the number of hooks at the ends of the steel fibers. The proposed correlation models were developed from the results of the 80 samples tested in this study and the 34 additional tests reported in previous studies. Results from Analysis of Variance helped to identify that correlations between the strength from 4PBT and DPT can be used for SFRC with compressive strength varying between 21 and 45 MPa. Results from box-and-whisker analysis show that the mean value of the calculated to measured strength and toughness ratios, associated to the developed correlations, are lower than and close to unity, which indicates that the prediction provides conservative results and close to the measured values. The correlations were developed using a practical functional form that can be easily implemented in design codes.

A method of reverse and revision of material mechanics performance parameters for vehicle collision simulation

In the process of vehicle collision, the steel material will be deformed by the impact speed. The stress under the same strain will be affected by the change of strain rate. The accuracy of the strain rate curve directly determines the accuracy of the model simulation. This article studies the optimization of material mechanical performance parameters and the correction reprocessing methods of the stress that cannot be obtained by the test in the strain interval. This paper proposes the principle of the modified constitutive equations and the corresponding formula. Based on the approximate model of thin-walled beam under the dynamic impact, the correction coefficient is obtained reversely. While ensuring the accuracy between fitting curve based on the material constitutive equation and the experimental data, the modified constitutive model solves the effect of the non-convergence of stress in a large strain region on the accuracy of the collision simulation model. The dynamic drop weight test results of thin-walled beams show that the modified constitutive equation has great significance for improving the accuracy of simulation models under high-speed impact conditions.

Demontažne spregnute međukatne konstrukcije od čelika i betona: pregled najnovijih izvedbi

In keeping with current demands for sustainable development in all segments of the industry, numerous research in the field of steel-concrete composite structures has been focused on developing demountable shear connectors. In the past years, various demountable shear connectors have been suggested, with various mechanisms for transferring shear force between a steel profile and a concrete or composite slab. In this paper, a state of the art on the topic is given, and experimental and numerical research results of push-out and beam tests are summarized.

Performance of the ISS-CREAM calorimeter in a calibration beam test

The Cosmic Ray Energetics And Mass experiment for the International Space Station (ISS-CREAM) was installed on the ISS to measure high-energy cosmic-ray elemental spectra for the charge range Z=1 to 26. The ISS-CREAM instrument includes a tungsten scintillating-fiber calorimeter preceded by a carbon target for energy measurements. The carbon target induces hadronic interactions, and showers of secondary particles develop in the calorimeter. The energy deposition in the calorimeter is proportional to the particle energy.As a predecessor to ISS-CREAM, the balloon-borne CREAM instrument was successfully flown seven times over Antarctica for a cumulative exposure of 191 days. The CREAM calorimeter demonstrated its capability to measure energies of cosmic-ray particles, and the ISS-CREAM calorimeter is expected to have a similar performance. Before the launch, an engineering-unit calorimeter was shipped to CERN for calibration and performance tests. This beam test included position, energy, and angle scans of electron and pion beams together with a high-voltage scan for calibration and characterization. Additionally, an attenuation effect in the scintillating fibers was studied. In this paper, beam test results, including corrections for the attenuation effect, are presented.

Shear strengthening of existing reinforced concrete beams with embedded bars – an overview

This paper presents an overview of the deep embedment (DE) method – also referred to as the embedded through-section method – a promising technique for concrete shear strengthening. The aim of this work was to collate pull-out and beam test results with a view to identifying existing gaps in knowledge. A careful evaluation of pull-out test results showed that, except for the effect of embedded length, the bond performance of DE bars epoxy-bonded into concrete is not fully understood. Analysis of beam test results identified significant gaps in knowledge, particularly with regard to the effect of concrete strength, loading type, shear span-to-effective depth ratio, size effect and DE bar surface coating. Moreover, the analysis of beam test results revealed a novel interaction between steel tension and DE shear reinforcement. Finally, yet importantly, the paper summarises the research required for robust implementation of the DE technique.

Recycling of plastic box waste in the concrete mixture as a percentage of fine aggregate

This study was conducted to assess the effect of plastic box waste particles (PBWPs) on the mechanical characteristics of a concrete mixture if plastic box particles (PBPs) are used as a partial substitute for sand in the mixture. Another purpose was to verify the effect of the waste on the flexural behavior of reinforced concrete beams (RCBs). In this research, four normal concrete mixtures with a water/cement ratio of 0.41 were examined. Three concrete mixtures contained recycled plastic box waste particles by varying the percentage of usage (2.5%, 5%, and 10%) and one mixture without PBPs as reference mixture (RNC) for comparison. To investigate the accuracy impact of the waste on strength and serviceability, three RCBs were tested with dimensions of 150 × 200 × 1400 mm, containing different proportions of the waste within the concrete mixture. Several tests were performed to detect the difference between the mechanical properties of a mixture containing plastic waste and the reference mixture. Cracking investigation, load- deflection behavior, ductility indices, initial stiffness, and secant stiffness were the RCB test variables. The concrete mixture with PBWPs considerably enhanced concrete properties. Results indicated that depending on the quantity of plastic particles replaced by fine aggregate, plastic may have an effect on strength. However, the test results demonstrated that the partial replacement of 5%PBWPs by weight in the mixture increased the compressive strength approximately 30.2%. Incorporating PBWPs into the concrete mixture did not significantly change the failure mode of RCBs compared with that of NC beams. However, the first crack load showed improved results in the hybrid beam (beam with two mixtures of different percentages of PBWPs). The reinforced concrete mixture, which contained 5% plastic particles, exhibited a slight increase during the ultimate failure load with an increment of 1.82%. Moreover, the results of the concrete beam test showed a prominent improvement in ductility, particularly in the hybrid beam; a small increase in the initial stiffness; and a slight decrease in the secant stiffness.

Commissioning of the next-generation LLRF control system for the Rapid Cycling Synchrotron of the Japan Proton Accelerator Research Complex

The low level rf (LLRF) control system has key roles for the stable acceleration of the high intensity beam. The original LLRF control system for the Rapid Cycling Synchrotron (RCS) of the Japan Proton Accelerator Research Complex (J-PARC) has been working nicely without major issues for more than ten years since the operation of the RCS started in 2007. Due to the obsolescence of the key digital devices, it is difficult to maintain the original system for a longer period, therefore we developed the next-generation LLRF control system based on the MTCA.4. All of the LLRF functions of the new system were tested and commissioned. In this article, we describe the commissioning of two key functions, the phase feedback to damp the longitudinal dipole oscillation and the multiharmonic vector rf voltage control feedback for twelve cavities. The commissioning methodologies and beam test results are presented. The stable acceleration of the high intensity beam at the design intensity of 8.3×1013 ppp is achieved. The next-generation LLRF control system has been successfully deployed and commissioned. This article is a follow-up of our previous articles, IEEE Transactions on Nuclear Science, 66 (7), pp. 1242-1248 (2019) and Phys. Rev. Accel. Beams 22, 092001 (2019).