bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Simulation of the Power Transmission System of extended range electric Vehicle based on MATLAB/Simulink
Authors: Zhang Chundong
Published: August 2023

With the rapid growth of automobile ownership, energy shortage and exhaust pollution have become the two major problems restricting the development of automobiles. Electric vehicles with zero fuel consumption and pollution-free advantages are the future direction of development. But battery technology is not mature at this stage, and the driving distance of electric vehicles is short. Extended range electric vehicle is a hybrid electric vehicle equipped with a range extender based on a pure electric vehicle. When the power is sufficient, the whole vehicle runs with pure electric power. When the power is insufficient, the range extender works to drive the vehicle. As a kind of electric vehicle that can extend driving range, the extended-range electric vehicle has great research significance at present. In this paper, based on MATLAB/Simulink platform, the simulation model of the vehicle power transmission system is built by using the experimental modeling method. According to the model, the dynamic performance simulation of the extended-range electric vehicle is carried out, and the rationality of parameter matching of the vehicle components is verified.
Fast detection of short circuits in low-voltage AC systems based on wavelet packet transform and current change rate
Authors: Yang Tao , Miao XiRen , Zhuang ShengBin
Published: August 2023

The safe and stable operation of a new low-voltage power system requires the research and application of fast detection technology of short-circuit faults. However, the existing methods are difficult to effectively realize the rapidity and reliability in case of short circuits with unclear features and various interference conditions. Therefore, the fault feature of short-circuit current in the full phase angle range is analyzed, and a new method of short-circuit detection based on wavelet packet transform and current change rate is proposed. Among them, the fast-action detection method of wavelet packet transform is used for faults with obvious features to achieve detection rapidity, and the double criteria backup detection method of wavelet packet transform and current change rate is used for faults with unclear features to ensure detection reliability. On this basis, the hardware technology realization of short-circuit fault fast detection algorithm is studied. For short circuit faults, load startup, load switching, and other situations, the real low-voltage AC system experiment is carried out to verify. Finally, the test shows that the detection method can effectively and rapidly detect short-circuit faults within 1ms in the full phase angle range, and has robustness under interference conditions.
Capacitor Voltage Weighted Full Feedforward Control Strategy for Adaptability Enhancing of LCL Grid-Connected Inverter Under Weak Grid
Authors: Li Zhihong , Wang Xiaogang
Published: August 2023

A capacitor-voltage full feedforward strategy is generally utilized to enhance the stabilization of the LCL grid-connected inverter. Meanwhile, the digitally controlled retardation leads to a phase lag of about 90° in the inverter’s export impedance on account of the introduction of the feed-forward loop, which influences the adaptation of the grid-connected inverter for a weakened grid. This investigation proposed a capacitor voltage-weighted full feedforward approach, which uses weighting coefficients to correct the inverter’s output impedance at various frequencies. In this way, the robustness of the grid-connected inverter operating at weak network conditions is improved. The proposal is validated by a combination of dramatic theoretical arguments and experimental findings.
Control Strategy Based on Improved Sliding Mode Control for T-type 3L PV Grid-connected Inverter
Authors: Sun Yang , Fan Zhengzhen , Yin Yuanya
Published: August 2023

This paper analyzes the mathematical model and working principle of a T-type 3 L PV inverter and introduces the control structure of a grid-connected PV inverter. In view of the influence of the sliding mode controller (SMC) rooted on the traditional reaching law (RL) on the control performance for grid-connected PV inverters as the current inner loop, such as large THD, this paper proposes a novel RL in the inner loop SMC to improve the tracking effect and robustness of the controller. The design method of each link of the SMC based on the proposed novel RL is described in the paper. Then, the stability analysis of the improved SMC is carried out. The experiment has been carried out on the experimental operating platform of the T-type 3 L PV grid-connected inverter system. The experimental results allow expressing that the designed control strategy can modify the dynamic performance of the system, reduce the harmonic distortion rate of the incoming current, and maintain the system with strong anti-interference capability under the premise of making the PV power generation system operate stably.
Collaborative configuration and optimal operation of cogeneration system based on phase change heat storage
Authors: Yu Changle , Ji Yanchen , Zhu Yuanda , Wang Junqi , Shi Xingcai , Li Yue
Published: August 2023

Given the low efficiency of heating and power supply caused by the low temperature in the Northeast during the heating process of the solar heat pump, the article first adds phase change hot storage device based on time-sharing control based on the traditional PVT collector — heat pump, and constructs a flexible thermoelectric coupling multi-energy system by shifting the peak and filling the valley; Secondly, based on TRNSYS software, the simulation model of PVT collector-heat pump-phase change heat storage-electrical coupling combined supply system is built. By comparing with the heat storage system using an ordinary heat storage tank, the results show that the phase change water tank system can significantly improve the system performance. Finally, Hooke-Jeeves is used to optimize the inclination angle, area, volume of the tank, and heating capacity of the air source heat pump of the PVT collector of the thermal-electric coupling system, to increase the system’s one-year operation.
Integrated Control Strategy of Voltage and Frequency Modulation for the Photovoltaic-storage Unit
Authors: Liu Hongwei , Zheng Zunguo
Published: August 2023

With the increasing installation of new energy power generation, photovoltaic power generation has become a significant component of the power system. However, the random and fluctuating nature of photovoltaic power generation can pose a challenge. The combination of photovoltaic power generation with energy storage using a photovoltaic-storage unit integrated machine can help mitigate the fluctuations of photovoltaic power generation output and improve the power quality of photovoltaic grid connection. In this paper, we propose a grid-connected integrated control strategy for the photovoltaic-storage unit integrated machine. We use a hybrid energy storage module with a lithium battery and a super capacitor as the energy storage unit for the photovoltaic-storage unit integrated machine. Finally, we use the MATLAB/Simulink simulation platform to simulate and verify the effectiveness of our proposed strategy.
Real-time economic and safe operation diagnosis of hydropower units
Authors: Wang Aizhen , Hu Shuxin
Published: August 2023

In order to ensure the safety and economy of the operation of hydropower units under the big data technology application platform and the automatic generation control system, and to tap the maximum power generation potential of the units, an effective method of economic operation evaluation of hydropower units combined with state diagnosis is proposed. Taking Unit 1 of Longtan Hydropower Station as an example, the economic evaluation and status diagnosis of the daily operating conditions are carried out, the real-time efficiency of the turbine is queried through the unit operating conditions data, and the economic operation of the unit is comprehensively evaluated using the standard water consumption index. In addition, the real-time operation condition of the unit shall be diagnosed according to the working condition zoning diagram, and the economic operation condition shall be combined with the unit state operation condition for joint assessment. It is strictly forbidden to operate the unit in the vibration zone and the vortex zone and it is determined that the unit can maximize the power generation efficiency after operating in the safe operation zone.
The modular design and verification of a 110kV circuit breaker
Authors: Su Yi , Pan Shaoming , Zhang Wei , Wang Jialin , Zhang Lei , Meng Ning , Li Weiguo , Gao Xingyu , Gong Ruilei
Published: August 2023

The reliability of circuit breakers is of great importance for the safe operation of the power grid. Most failures of the circuit breakers were caused by their operating mechanism, which often contains a lot of components. What is more, the secondary connections of the circuit breakers are also complicated. The lack of modular design of domestic circuit breakers now limits the development of reconditioning. To improve the reliability and reduce the maintenance time of the circuit breaker, research on the modular design of a 110 kV circuit breaker has been carried out and the verification was also conducted.
The influence of the length of parallel mechanism on path planning
Authors: Li Ji Ze , Yang Tao
Published: August 2023

The path planning of the parallel mechanism should not only consider the motion path of the end effector but also the motion path of the member. As an important factor affecting the workspace of parallel mechanisms, links do not participate in path planning. To realize the intelligence of path planning for parallel mechanisms, a method to determine and modify the feasibility of path planning is proposed based on the parallel 6-DOF attitude adjustment platform. First, the kinematic inverse solution of the motion path of the end effector is carried out to obtain the motion path of the six struts. At the same time, the corresponding workspace is obtained according to the change in the length of the struts, Finally, based on the intersection of the motion path and workspace of the six struts, the success of path planning is determined, and the corresponding path modification method is given. Through the actual experiment and MATLAB simulation, the results show that this method can avoid the motion stop phenomenon caused by a single strut passing through the non-workspace in the path planning of the parallel mechanism.
Verification of the Heat protection and Cooling Effects for Thermal Barrier Coating on Turbine Blade
Authors: Li Shifeng , Zhang Jianqiang , Yang Dengwen , Huang Kang
Published: August 2023

Aiming at the difficulty of directly testing the heat protection effect of thermal barrier coating (TBC) on turbine blades in real working conditions of Aero-engines, in order to obtain the heat protection performance and TBC cooling effect on turbine blades, this study first conducted a simulation test of heat protection effect at 1100K test temperature on a tester, and then combined with the test results of TBC heat protection effect, completed the verification in real working conditions of Aero-engine. The test results verify that the actual heat protection effect of the TBC is roughly equivalent on the suction surface and pressure surface of the blade, but it is the worst in the trailing edge region with the blade basin, with an average relative cooling efficiency of about 0.642 in the middle section, and a maximum absolute heat protection effect of about 41 K. At the same time, the blade has no ablation phenomenon, and the TBC is in good state on the blade surface, and it is free of defects such as cracks, wrinkling, and peeling, as verified by the coupon test with a maximum gas temperature of 1800K for a cumulative period of 21 hours.
Multi-objective rapid optimization method for a variable-stroke valve train device
Authors: Duan Shuhua , Cui Jingchen
Published: August 2023

Raising the maximum valve lift in two-stroke drive mode is the key to increasing the power output of the variable-stroke engine, so the limit design of the variable-stroke valve train device is critical. The multi-objective genetic optimization algorithm NSGA-2 was coupled with the single-freedom dynamics model of the variable-stroke valve train device. A multi-objective rapid optimization program for the valve train device was constructed in Matlab. Two optimization methods explored the maximum valve lift limit in two-stroke drive mode. The first was to optimize the rocker structure, and the second was to optimize the cam position and the rocker structure together. The results show that the single-freedom dynamics model has sufficient computational accuracy. The collaborative optimization results of the cam position-rocker arm structure are more optimal. Under the same maximum lift of the valve, compared to the results of individual optimization of the rocker arm structure, the maximum contact force is reduced by up to 285 N. The maximum contact stress is reduced by up to 63 MPa through collaborative optimization. Compared with the original case, the maximum increase rate of the maximum valve lift obtained through optimizing the rocker structure is 12.45%, while that obtained through collaborative optimization is 12.85%.
The overall structural design of the culverted flyer layout aircraft and the angle-of-view characteristics
Authors: Zhou Zijie , Yang Wenshuo , Xiong Guangchang , Chen Jinhao , Ma Mingyuan , Tang Peng , Zhang Heyi
Published: August 2023

In view of the advantages of both vertical landing and flying wing layout aircraft, the culverted rotor has the advantages of a larger thrust-to-weight ratio and higher net lift efficiency. The culverted rotor is used to achieve a vertical landing. Landing of the aircraft will be an important research direction in the future. This type of aircraft can realize the automatic closing of the upper and lower culvert closing plates when the vertical landing and landing state is changed to the high-speed level flight state. This paper gives a detailed overview of the overall mechanical design of this new culverted wing layout aircraft. Then it analyses that the wing surface aerodynamic characteristics of the culverted wing layout aircraft change abruptly before and after the transition state. This is because the closure of the closing plate achieves a rapid change in the angle of orientation to avoid the degradation of the aircraft’s aerodynamics. The angle of orientation of the wing should be calculated before and after the two states.
Analysis of Influence of Pre-bend Blade Shape on Aeroelastic Characteristics of Wind Turbine Under Startup Condition
Authors: Li Qi , Gao Zhiying
Published: August 2023

In this paper, a 2 MW wind turbine in the laboratory is taken as the research object, and the blades with pre-bending capacities of 2, 3, 4, and 5 m are designed, respectively, to study the influence of different pre-bending capacities on the aerodynamic elasticity of wind turbine under unstable operating conditions. Based on the professional simulation software of wind turbine multi-body dynamics, the parametric model with aero-elastic-control coupling is established, and the simulation calculation of different pre-bending blades is carried out. The results show that the aerodynamic deformation of the blade and the load at the blade root increase obviously with the increase of blade pre-bending. Under the starting condition of a wind turbine, larger blade pre-bending will lead to a significant increase in aerodynamic deformation of wind turbine blades under unstable operating conditions. It shows that the larger blade pre-bending amount will greatly increase the risk of aeroelastic instability of wind turbines under unstable operating conditions.
Study on the Method of Tilt Error Compensation for a Laser On-machine Measurement System
Authors: Zhang Rong , Su Huanhuan , Wei Jialin , Shi Jie , Cui Xiaohang , Yu Junyu , Yao Yonghong , Dong Ying , You Lei , An Nan
Published: August 2023

This paper proposes a spindle vector compensation method based on laser triangulation for the inclination measurement error of a laser on-machine measurement system. By using the fixed relationship between the calibration vector and the spindle vector, the laser’s axis vector and the surface’s normal vector coincide in the actual measurement by adjusting the spindle vector. The tilt measurement and calculation errors are compensated simultaneously using this spindle vector compensation method.
Engine Sonic Load Prediction of Blended Wing Body Aircraft
Authors: Cen Yipeng , Xu Jiaxin , Yang Mingming
Published: August 2023

The sonic load of the engine is the input for cabin noise design and acoustic fatigue verification in civil aircraft. Based on the engine static noise database, an engineering prediction method for blended wing body aircraft engine sonic load in flight is developed. In the process of sonic load prediction, the sound source position correction, geometric diffusion, flight effect and airframe scattering effect of engine component noise are considered. The flight effect and air-frame scattering effect of engine component level noise are simulated and analyzed. The overall sound pressure level distribution and sound load spectrum at typical positions of blended wing body aircraft engine are given. The results show that fan inlet noise is the most important component of the engine sonic load on the BWB aircraft surface, and the maximum value of engine sonic load on the upper surface of blended wing body aircraft is 134 dB, which is higher than that of conventional wing crane aircraft.
The angle of attack and side-slip angle estimation for civil aircraft
Authors: Liu Jun
Published: August 2023

The angle of attack and side-slip angle are two important flight parameters that directly affect the flight safety of civil aircraft. This paper studies the estimation method for the angle of attack and side-slip angle according to air-data system, inertial navigation system, and aircraft aerodynamic data to improve flight safety under the condition of icing, failures, and improper maintenance. Flight tests show that the proposed estimation method is feasible, reliable, and has better accuracy. Furthermore, flight test data analysis shows that the angle of attack estimation error is within 1 degree, and the side-slip angle estimation error is within 1.5 degrees which can meet the requirements of engineering application.
Numerical Investigation of Blade-to-Blade Surface Layout in the Ram-rotor
Authors: Guan Jian , Han Ji’ang
Published: August 2023

A numerical investigation has been conducted on the ram-rotor with various blade-to-blade profiles to achieve potential benefits in enhancing their performance. The blade-to-blade profile is changed by adjusting the strake camber line to enable the formation of expansive and contractive flow paths. Results indicate that the expansive flow path can significantly improve the total pressure ratio of the ram-rotor by altering the position of shock trains. Subsonic airflow after the shock train is decelerated and pressurized, which further contributes to the pressure rising capacity. The leakage flow is suppressed as the flow path is contractive in the blade-to-blade view. This, in turn, leads to a significant reduction of both tip leakage loss and the interference effect between the leakage and the shocks.
A Parameter Correction method of CFD based on the Approximate Bayesian Computation technique
Authors: Zhang Xinfang , Li Miao , Wang Bomin , Li Zexian
Published: August 2023

Numerical simulation and modeling techniques are becoming the primary research tools for aerodynamic analysis and design. However, various uncertainties in physical modeling and numerical simulation seriously affect the credibility of Computational Fluid Dynamics (CFD) simulation results. Therefore, CFD models need to be adjusted and modified with consideration of uncertainties to improve the prediction accuracy and confidence level of CFD numerical simulations. This paper presents a parameter correction method of CFD for aerodynamic analysis by making full use of the advantages of the Approximate Bayesian Computation (ABC) technique in dealing with the analysis and inference of complex statistical models, in which the parameters of turbulence models for CFD are inferenced. The proposed parameter correction method is applied to the aerodynamic prediction of the NACA0012 airfoil. The results show the feasibility and effectiveness of the proposed approach in improving CFD prediction accuracy.
Survey of Noise-Against Techniques for Extracting Stable Skeleton
Authors: Liu Yuan , Ma Jun , Ren Xunhuan , Li Hao
Published: August 2023

Stable skeletons are promising as a compact, concise, and efficient descriptor since they can reflect much critical information about the original object, such as topology, connectivity, etc. However, extracting stable skeletons from images is very challenging since most existing skeleton extraction methods, also named skeletonization methods in some literature, are sensitive to noise, which limits the application of the skeletons in the recognition field. Many denoising methods have been proposed to extract stable skeletons to overcome this problem. However, up to now, there are few review papers to conclude these denoising methods and present their pros and cons. Therefore, In this paper, we survey existing denoising techniques for extracting stable skeletons from images. We first categorize these denoising methods, analyze their core idea, and then present their pros and cons for comparison. In addition, we also offer the potential research direction and possibly challenge.
Dynamic Probabilistic Broadcast based on Neighbour Discovery
Authors: Xiaoying Shuai
Published: August 2023

Broadcasting in Ad hoc networks is an important information dissemination way. However, flooding may give rise to broadcast storm problem which causes severe contention, collision and delay. This paper proposes a dynamic probabilistic broadcast algorithm based on neighbour discovery that ensures the higher reliability at lower retransmission. The dynamic probabilistic broadcast algorithm forwards the information from the node (INode) that has obtained it to the node (UNode) that has not received it. By counting the number of UNode and INode of neigbors, INodes dynamically adjust the probability of broadcasting to reduce the number of information replication but cover more UNodes. Dynamic probabilistic algorithm can not only effectively reduce the number of retransmission, but also ensure the effectiveness and reliability. Simulation results show that the number of broadcasting of this algorithm is significantly lower than other algorithms.
Stacking Ensemble Learning for the Modulation Recognition of Underwater Acoustic Communication Signals
Authors: Wang Dezhi , Deng Mengsha , Cheng Xinghua , Bao Changchun , Yin Mei , Gao Kai , Zhao Wenbo
Published: August 2023

Effective detection and recognition of underwater acoustic communication signals is of great significance in the field of ocean exploration. In this paper, a novel deep-learning recognition method of modulation modes of underwater acoustic communication signals is proposed. The stacking ensemble learning framework is established on the basis of several single deep-learning classifiers with different network structures and parameter configurations. The proposed method achieved an average recognition accuracy rate of more than 95% on the dataset generated under a simulation environment. The performance is also verified by means of a comparison with the classic SVM method.
Vibration analysis of functionally graded microbeams with a moving mass based on Timoshenko beam theory
Authors: Vu An Ninh Thi , Pham Vu Nam , Bui Van Tuyen , Nguyen Dinh Kien
Published: August 2023

Vibration analysis of functionally graded (FG) microbeams carrying a moving mass is carried out in the framework of Timoshenko beam theory. The beam material properties are considered to be graded in the thickness by a power-law function, and they are estimated by Mori-Tanaka scheme. The influence of the microsize effect is captured with the aid of the modified couple stress theory (MCST). A finite beam element is formulated and used to establish the discretized equation of motion for the beams. Vibration characteristics, including the natural frequencies, the time histories for mid-span deflection, the dynamic magnification factor and the stress distribution, are computed for a simply supported beam. The obtained result reveals that both the dynamic deflection and dynamic magnification factor are overestimated by ignoring the microsize effect. The effects of the material distribution, the moving mass velocity and the length scale parameter are studied in detail and highlighted.
Study on dynamic impact factor of girder bridges due to vehicle load model
Authors: Tran-Van Duc , Nguyen-Xuan Toan , Nguyen-Duy Thao , Nguyen-Thi-Kim Loan
Published: August 2023

The dynamic effects of moving vehicle on bridge are generally treated as withstand static loads that are recommended an increment by dynamic impact factors (IMs) (or dynamic amplification factors) in many design codes, that are a function of either the span or the first flexural natural frequency of the bridge. The value of the IM will relate to safe and economical in new bridge designs, evaluate recommendation and operation of bridges. Due to the bridge-vehicle interaction model, previous studies have shown that the calculated IM from field measurements could be higher than the values specified in design codes. Currently, studies on IM often focus on using interaction models with multi mass vehicles move on bridge that are increasingly similar to real models. This study develops a 2D three-axle vehicle–bridge model to analysis the dynamic response of the girder bridge subjected to moving loads consider to some vehicle parameters with the each axle is modelled in two masses, each mass is connected to a spring and a damping corresponding to the suspension and tire. In addition, depending on the stiffness parameters of the suspension and tires of the analyzed vehicle model, the IM results of this study are different from those of some authors and the bridge design rules. Based on the dynamic analysis of the bridge under the vehicle loading consider the stiffness of tire and suspensions, the calculation of the IM needs to be considered more carefully in the process of designing new bridges or existing bridges.
Seismic behavior of cable-stayed bridges under strong ground motions
Authors: Vern S , Paolacci F , Nascimbene R
Published: August 2023

Seismic behavior analysis of the long-span cable-stayed bridge is a complex process involving different uncertainties. This paper performs a sensitivity analysis of cable-stayed bridges using the finite element method on Midas/Civil. They include different types of ground motions scaled to different peak ground acceleration (PGA) levels, the effect of the multi-support excitations due to time-lag propagation or nonsynchronous excitations, and the effect of the angle of the incidence of the earthquake is determined. To evaluate the optimum initial cable prestress forces in cables unknown load factors method is used. The response quantities of interest include the displacement of the tower and deck, variation in prestress force in cables, torsional in the deck, shear force, and bending moment at the supports. Results show that the effect of the PGA variation and angle of incidence of the earthquake is moderate. In contrast, the synchronous and nonsynchronous seismic excitation effect on the response quantities is significant.
Landslide susceptibility modeling and mapping at Dien Bien province, Vietnam using Bagging based MLP neural network
Authors: Nguyen Dam Duc , Le Hiep Van , Pham Binh Thai
Published: August 2023

In this article, the main aim is to build landslide susceptibility map at the Dien Bien province (Vietnam) using a hybrid machine learning model including BG-MLP which is a hybridization of Bagging and Multilayer Perceptron (MLP) neural networks. For this purpose, 665 past landslide events together with 665 non-landslide locations and 10 landslide influencing parameters including geology, normalized difference vegetation index (NDVI), distance to roads, distance to rivers, topographic wetness index (TWI), slope, curvature, aspect, distance to faults and elevation were collected and used for generation of datasets for model’s development and validation. To validate the predictive capability of the model, area under the ROC curve and other popular statistical indices were used. Results presented that BG-MLP (AUC = 0.81) has a good performance in modeling and mapping landslide susceptibility at the study area, especially its performance is better than single MLP model (AUC = 0.78). Thus, it can be concluded that BG-MLP is powerful tool that can be employed for assessment of susceptibility of landslides in other landslide prone regions of the world. Map of landslide susceptibility created from this study would be useful for decision making and land use planning in reducing the harmful impacts of landslides.
Simulate landslide activities during flood season 2020 - 2021 in Phong Nha - Ke Bang National Park
Authors: Do Thien Quang , La Duong Hai , Ho Hoang Tung , Nguyen Thi Thanh Nhan , Tran Thanh Nhan , Chinkulkijniwat Avirut
Published: August 2023

Research highlights in study area, there are various small-scale landslide points occurred and located surround from major landslide point with already 42 field-investigated points. The core zone of study area has the gravity displacement coefficient (Kg) by 0.0006, the buffer zone has Kg by 0.0033, all of them are weak and relative stable. The core zone of the National Park has more than 60 landslide points with total area of 81.19 hectares, and total landslide soil volume is over 2.6 mil m3. The largest landslide volume in study area is about 2.4 mil m3, with added 14 large-scale lanslide volume from 1,000 to 65,000 m3. In particular, a number of slopes occurred consecutively during flood seasons in years of 2020 - 2021. Landslide activities strongly affecting the integrity and aesthetic value of Phong Nha – Ke Bang (PNKB) National Park with calculation results, for the largest landside point during rainny season in October, 2020, show that the sliding soil blocks have displaced more than 130 m, with low factor of safety (FS) by 0.32 and the total sliding soil volume is 2.1 million m3, also consistent with field monitoring data and analysis of remote sensing images (2.4 mil m3).
Experimental study on bending fatigue strength of adhesively bonded joints
Authors: Thay Visal , Osada Yuna , Kanazawa Yuta , Fujikura Shuichi , Nakamura Hitoshi , Horii Hisakazu
Published: August 2023

This paper focuses on the establishment of repair or strengthening method of steel structures by externally bonded patch plates. The bending static tests and bending fatigue tests of adhesively bonded joints were conducted and the fatigue life is evaluated. The Konishi E258R is used as an adhesive, and the bending fatigue tests were conducted, varying the applied stress ranges and the stress ratio, the ratio of minimum and maximum stress of fatigue test. The result indicates that the fatigue life of adhesively bonded joints can be evaluated in the function of principal stress ratio, the ratio of principal stress range against principal stress at debonding by the bending test, with constant linearity regardless of the stress ratio.
Compression self-sensibility of the concrete using high content carbon black with various measurement conditions
Authors: Chi Vo Minh , Lan Nguyen , Hai Nguyen Minh , Huong Nguyen Van
Published: August 2023

Self-sensing concrete (SSC) is a smart material created by dispersing a conductive filler into the concrete. This helps to increase the resistivity variation of concrete when the microstructure of the material changes under the effect of load. Thus, the stress, strain or damage of the concrete can be sensed by resistivity measurements of the concrete itself. This study aims to clarify the effects of parameters related to the measurement method on the self-sensibility of SSC. SSC specimens were prepared using carbon black with 7% volumetric content. A series of compression tests were conducted to investigate the relationship between the resistivity variation and the applied load of different test specimens in terms of excitation voltage, electrode distance and specimen size. The results show that the excitation voltage need to be large enough to generate a current of suitable stability when measuring the self-sensibility of SSC. The resistivity of all specimens decreased with increasing compressive load on the SSC specimen. The larger the specimen size and the smaller the electrode distance, the more pronounced the resistivity variation.
Building information modeling integrated with damage detection algorithm for structural health monitoring of bridge
Authors: Truong My-Pham , Dang Ngoc-Loi , Cao Van-Tuan , Ngo Trung-Chanh
Published: August 2023

In this paper, a method for damage monitoring of bridges using modal parameters is presented. At first, fundamentals of frequency-based damage occurrence alarming are introduced. Second, building information modeling (BIM) software is used to construct a 3D geometric model of a bridge. A custom tool add-in based on Microsoft Excel is linked and analyzed related data for damage detection of the bridge using modal parameters. A finite element model of a bridge girder is established to investigate vibration characteristics under prestressing loss and structural damage. Frequency-based damage detection is implemented to alarm the damage occurrence of an inspected bridge girder. Last, the structural information of the bridge is updated to the BIM model to provide the structural performance of the inspected structure. The result reveals that BIM integrated with the damage detection algorithm can efficiently facilitate structural health bridges.
Investigating the qualities of grouting material used modifiers in the semi-flexible pavement
Authors: Do Thi My Chinh , Nguyen Manh Tuan
Published: August 2023

Semi-flexible pavement has a more notable advantage over asphalt concrete pavement in terms of rutting performance. Cement grouting and open-graded asphalt concrete are components of the semi-flexible pavement. In cement grouting, two commercial modifiers from Sika Vietnam were used, Sika Latex and Sika TH Latex, with different contents from 4.5% to 7.5% for Sika Latex and 7.5% to 9.5% for Sika TH Latex. 72 samples of cement mortar were fabricated in laboratory conditions from PCB40. All cement grouts were cured at the age of 7 days. The paper results focus on the flexural strength and the compressive strength of both mortars, the suggestion of Sika content to produce the stable strength of cement grout, and the viscosity of cement mortar based on the Sika contents.
Proposing Binary Gravitational Search Algorithm Parameters for Back-calculation of Road Pavement Moduli
Authors: Le Dinh-Viet , Pham Ngoc-Phuong , Nguyen Quang-Phuc , Phan Cao-Tho
Published: August 2023

A Falling Weight Deflectometer is popular equipment to measure surface deflections under imposed loadings, providing the necessary parameters for back-calculating the elastic moduli of road pavements. There are several back-calculation programs available that accurately back-calculate pavement layer moduli. The Gravitational Search Algorithm (GSA), a metaheuristic optimization algorithm inspired by Newton’s law of universal gravitation, is one such algorithm. The Binary Gravitational Search Algorithm (BGSA) is an enhancement algorithm based on GSA that can be used as an efficient search algorithm for back-calculating pavement moduli based on matching measured and calculated surface deflection of road pavements. Choosing the best BGSA parameters is critical for accurate back-calculation of road pavement moduli. Nevertheless, there has not been much study on selecting the best BGSA parameters for back-calculating road pavement moduli in the literature. Therefore, this study proposes strategies for selecting BGSA parameters based on the least computational effort and the least root mean square error between measured and calculated road pavement surface deflections. In this study, the Burmister theory is discussed and the Richardson extrapolation is adopted to improve the accuracy of the calculated points near the pavement surface; the best parameter of BGSA including the agent size A of 50 and an iteration step T of 300 are suggested to back-calculating the road pavement moduli.
Infrared imaging for detection of defects in concrete structures
Authors: Singla Ritika , Sharma Shruti , Sharma Sandeep Kumar
Published: August 2023

Deterioration of concrete structures is an issue that affects the entire world and is brought on by various causes like climatic conditions, aging, attack of aggressive media, etc. Periodic inspections and proper maintenance are crucial to prevent the degradation of structures. Conventionally, the condition of the structures is monitored visually but over a while, non-destructive evaluation (NDE) technologies have gained significance and are expected to be successfully used for the inspection and management of civil structures. Infrared imaging is an effective NDT tool to monitor the health of civil structures. In this study, Infrared Thermography (IRT), an image-based method, is introduced and implemented for the assessment of concrete structures. Experiments on cement concrete cubes were conducted to investigate and enhance the applicability of the infrared thermography technique. The results are quite promising and helps to detect defects like delamination, voids, and cracks, etc. as the IR camera can pick-up the difference in temperature between sound and defective regions. However, the utilization of IRT for inspection poses many challenges but they can be overcome by combining it with other techniques like finite element method, acoustic emission and ultrasonic guided waves. Hence, the infra-red thermography technique is an excellent technology for practically evaluating concrete structures.
Strength development and microstructure evaluation of cement mortar incorporating various waste red brick powder
Authors: Ngo Thi-My , Vo Duy-Hai , Phan Nhat-Long , Nguyen Hoang-Anh
Published: August 2023

This research aims to evaluate the strength development and microstructure of a green mortar produced from waste red brick powder (WRP) as a partial cement replacement. The mortar samples were prepared with various WRP content of 0%, 10%, 20%, 30%, and 40% of total binder weight, and the w/b was fixed at 0.4. The fresh properties were checked by flowability and fresh unit weight. While the compressive strength was conducted up to 28 days. The mortar samples exhibited a reduction in flowability and unit weight with increasing WRP content. The incorporation of 10%-20% WRP improved the compressive strength of mortar samples at 28-day, while the compressive strength reduced with higher WRP content (30%-40%). The C-S-H/CaCO3 gel, Ca(OH)2 and ettringite were hydration products of WRP mortar samples. The incorporation with WRP significantly reduced the Ca(OH)2 content
Numerical investigation of the punching shear resistance capacity of reinforced concrete slab
Authors: Pham Thanh Binh , Mai Viet-Chinh , Nguyen Van Tu , Dao Cong-Binh
Published: August 2023

The article studies the punching shear capacity of reinforced concrete slabs by simulation method. Based on the Concrete Damage Plasticity (CDP) constitute model, the simulation model is established in the Abaqus software. The simulation model was verified by the comparison of punching shear tests. The parametric studies were implemented to investigate the effect of concrete and steel strength on the punching shear resistance capacity of the reinforced concrete slab. The punching shear resistance capacity of reinforced concrete slab was also calculated by the formulas proposed by available standards. Obtained results show that increasing concrete strength leads to a significant increment in the punching shear resistance capacity of slabs while the influence of steel strength is slight.
Investigation on the performance of polymer-modified stone matrix asphalt for bus rapid transport pavement
Authors: Lee Sang Yum , Le Tri Ho Minh
Published: August 2023

The application of the bus rapid transport (BRT) system has developed in many metropolitan cities owing to its cost-effective transportation which separates the bus routes from the private car route. However, the channelized bus load caused by narrow space operation in this road type leads to very fast pavement deterioration, especially, potholes and rutting issues have been a major concern in BRT pavement. Therefore, the main goal of this research is to develop a polymer-modified stone matrix asphalt (PSMA) with the aim of enhancing the permanent deformation resistance of pavement in this BRT section. PSMA mix designs were developed from different styrene-butadiene-styrene admixture contents and gradation types. Afterward, laboratory tests were conducted to evaluate the performance of the proposed mixture involving the dynamic modulus test and Hamburg wheel tracking test. The Falling Weight Deflectometer test was subsequently performed to verify the behavior of the best mixture in the severely damaged bus stop location in Seoul. The findings suggest that gradations impose a major impact on the performance of PSMA specimens, especially at high temperatures or low-frequency zone associated with congestion areas. In general, the test results confirmed the potential use of PSMA mixture to reinforce the bearing capacity of bus stop stations for sustainable infrastructure development.
Environmental Assessment of Limestone Calcined Clay Cement in Australia
Authors: Huang Guangtong , Zhuge Yan , Benn Bernard Thomas (Tom) , Liu Yue
Published: August 2023

The Australian government aims to achieve net-zero carbon emissions by 2050. Therefore, introducing a market-oriented carbon emissions trading scheme to offer a financial reward (or penalty) to those who emit below (or beyond) the allowed limits is expected. Under such a scheme, the cement industry is forced to reduce its energy consumption and carbon emissions. Limestone calcined clay (LC3) cement has been extensively studied and regarded as a promising solution to substitute ordinary cement clinker up to 50% without compromising the performance of concrete. In this paper, a comparative life cycle assessment (LCA) of the LC3 mortar considering cradle-to-gate system boundaries is conducted for the scenario in Australia. The LCA is undertaken on 122 collected LC3 mortar mix designs, and it includes the modification of traditional cement production to incorporate the calcined clay manufacture and evaluation of the environmental impact of different substitution levels. Results show that CO2 emissions associated with LC3 system production were reduced by up to 38% compared to Ordinary Portland cement mixtures.
Experimental and numerical evaluation of axial compression strengthening for corroded square reinforced concrete columns by carbon textile reinforced concrete
Authors: Dinh Huu Tai , Ngo Dang Quang , Ho Hoai , Nguyen Huy Cuong
Published: August 2023

This research focuses on analyzing the behavior of reinforced concrete (RC) columns under axial compression, both in their uncorroded and corroded states, through a combination of experimental and numerical investigations. For the experiment, seven specimens were prepared and manufactured subjecting to centric compression. The cross-sectional side length of the square columns was 200 mm. The column height was selected as 800 mm based on the dimensions of the testing machine. The specimens were divided into three groups: (i) the control columns, (ii) the corroded columns without strengthening, and (iii) the corroded columns strengthened with an external carbon textile reinforced concrete (TRC) layer. The experimental results showed that when the corroded columns had approximately 10% mass loss in longitudinal reinforcement and stirrups, the ultimate load was reduced by 5.7%. Meanwhile, the axial compression capacity of corroded columns strengthened by TRC layer was approximately 28% higher than the corroded unstrengthened ones. All tested specimens failed due to the buckling of the longitudinal reinforcement. The strengthened columns failed at the corners due to the rupture of the textile reinforcement. To validate the experimental results, a finite element (FE) modeling was presented.
Performance assessment of concrete considering the composition of coarse recycled aggregate
Authors: Nguyen Tien-Dung , Bastidas-Arteaga Emilio , Cherif Rachid , Mahieux Pierre-Yves , Lux Jérome , Aït-Mokhtar Abdelkarim
Published: August 2023

This study presents recycled aggregate concrete (RAC) properties considering coarse recycled aggregate (CRA) composition. The CRA is prepared by a French company with a fraction of 5-20 mm. The composition variability is created using a replacement coarse natural aggregate (CNA) ratio with CRA at 40%, 60%, and 80%. The composition CRA is determined by using convolutional neural networks (CNNs). The mix proportion for RAC used water to cement ratio (W/C) is 0.6, and the slump was 18-20 cm after one hour. The performance of RAC is assessed using compressive strength, porosity, and chloride diffusion coefficient. The results were compared to those for the original concrete. This paper shows the main results of evaluating the critical composition of recycled aggregate (RA), such as coarse recycled concrete aggregate, natural aggregate (NA), recycled brick, and tiles, on the properties of RAC.
A Comparative Study of UAV Lidar, UAV, and GNSS RTK on Infrastructure Survey
Authors: Vu Ngoc Quang , Nguyen Viet Ha , Ta Le Binh , Van Hung Tien
Published: August 2023

The advancement of the latest techniques allows surveyors to have various approaches to solving survey tasks. The paper is an experimental study on collecting terrain data using different techniques including Lidar on a UAV, normal UAV, and GNSS-RTK. The study uses the point clouds extracted from Agisoft for data from Phantom 4 RTK, and Copre for data from Lidar. The lidar method uses AA450, the first lidar product line of the CHC brand in Vietnam with a Livox Avia scanner. UAV phantom4 RTK uses a 1” CMOS camera, with 20M effective pixels. Both Lidar and UAV methods use the PPK processing technique, and flight altitude is 80m and 100m respectively while GNSS-RTK uses the single-base method at around 7km distance between base and rover. The study results show the deviations in coordinates are very small, and the differences in elevation of Lidar and Phantom4 RTK compare to GNSS-RTK range from 3-5cm at open positions. The differences in elevation between Lidar - GNSS-RTK and Phantom 4RTK-GNSS RTK are 5-8cm and 10-15 cm respectively at the low vegetation and sparse density positions. The differences in elevation between Lidar and GNSS-RTK method range from 8-15cm while Phantom 4RTK cannot reach the ground point at the high and dense vegetation. However, the deviations in elevation between Lidar and GNSS-RTK are 15-25cm at the low, dense positions.