Study on Pollen Viability, Longevity and Pistil Receptivity of Self-Compatible Chrysanthemum with Small Inflorescences

Hongbo Zhao,Fadi Chen,Yanfang Wang,Weimin Fang,Sumei Chen,Weiming Guo 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Numerical Simulation of Transport Phenomena for Laser Full Penetration Welding

Zhao, Hongbo,Qi, Huan The Korean Welding and Joining Society 2017 대한용접·접합학회지 Vol.35 No.2

In laser full penetration welding process, full penetration hole(FPH) is formed as a result of force balance between the vapor pressure and the surface tension of the surrounding molten metal. In this work, a three-dimensional numerical model based on a conserved-mass level-set method is developed to simulate the transport phenomena during laser full penetration welding process, including full penetration keyhole dynamics. Ray trancing model is applied to simulate multi-reflection phenomena in the keyhole wall. The ghost fluid method and continuum method are used to deal with liquid/vapor interface and solid/liquid interface. The effects of processing parameters including laser power and scanning speed on the resultant full penetration hole diameter, laser energy distribution and energy absorption efficiency are studied. The model is validated against experimental results. The diameter of full penetration hole calculated by the simulation model agrees well with the coaxial images captured during laser welding of thin stainless steel plates. Numerical simulation results show that increase of laser power and decrease of welding speed can enlarge the full penetration hole, which decreases laser energy efficiency.

Coupling relevance vector machine and response surface for geomechanical parameters identification

Zhao, Hongbo,Ru, Zhongliang,Li, Shaojun Techno-Press 2018 Geomechanics & engineering Vol.15 No.6

Geomechanics parameters are critical to numerical simulation, stability analysis, design and construction of geotechnical engineering. Due to the limitations of laboratory and in situ experiments, back analysis is widely used in geomechancis and geotechnical engineering. In this study, a hybrid back analysis method, that coupling numerical simulation, response surface (RS) and relevance vector machine (RVM), was proposed and applied to identify geomechanics parameters from hydraulic fracturing. RVM was adapted to approximate complex functional relationships between geomechanics parameters and borehole pressure through coupling with response surface method and numerical method. Artificial bee colony (ABC) algorithm was used to search the geomechanics parameters as optimal method in back analysis. The proposed method was verified by a numerical example. Based on the geomechanics parameters identified by hybrid back analysis, the computed borehole pressure agreed closely with the monitored borehole pressure. It showed that RVM presented well the relationship between geomechanics parameters and borehole pressure, and the proposed method can characterized the geomechanics parameters reasonably. Further, the parameters of hybrid back analysis were analyzed and discussed. It showed that the hybrid back analysis is feasible, effective, robust and has a good global searching performance. The proposed method provides a significant way to identify geomechanics parameters from hydraulic fracturing.

Reliability-based Optimization of Geotechnical Engineering using the Artificial Bee Colony Algorithm

Hongbo Zhao,Ming Zhao,Changxing Zhu 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.5

The performance and safety of a geotechnical engineering system are affected by uncertainties. The purpose of Reliability-Based Optimization (RBO) is to find a balanced design that is not only economical but also reliable in the presence of uncertainties. Numerous reliability optimization techniques have been proposed. In this study, the Artificial Bee Colony (ABC) algorithm is employed for reliable optimization of a geotechnical engineering system. The proposed ABC-RBO method combines ABC and First Order Reliability Methods (FORM). Optimization is performed with ABC, while the reliability analysis is performed with FORM, incorporating Excel solver. The proposed method is verified by two geotechnical engineering examples and compared with other methods, and shown to be robust, accurate, and feasible.

Sparse Polynomial Chaotic Expansion for Uncertainty Analysis of Tunnel Stability

Hongbo Zhao,Meng Wang,Bingrui Chen,Shaojun Liu 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.9

Uncertainty is an intrinsic property of rock engineering because of the complicated geology conditions, rock failure mechanism ambiguity, and the nonlinear mechanical behavior of surrounding rock mass. We developed a novel framework to handle the uncertainty by combing the Sparse polynomial chaotic expansion (SPCE), numerical model, and reliability method. The SPCE model was used to map the complex relationship between the response of the surrounding rock mass and its uncertainty. The first-order reliability method (FORM) evaluated the reliability index and failure probability. Based on the SPCE model and FORM, a simple global optimization algorithm (SHGO) seeks design points and corresponding reliability indexes. A circular tunnel verified the developed framework with a close-form solution. The reliability index, design point, and failure probability were in excellent agreement with the FORM and Monte Carlo simulation. This indicated that the SPCE model could be used as a surrogate model for the analytical solution to approximate the tunnel response (including deformation and size of the plastic zone). Then, the developed framework was employed in a horseshoe tunnel by combing with the numerical model. The results further proved that the developed framework is feasible and effective for handling uncertainty in rock engineering. Furthermore, the developed framework is effective, efficient, and accurate for reliability analysis and provides a helpful tool to approximate the response of rock structure to avoid the time-consuming numerical model in practical rock engineering.

Numerical Simulation of Transport Phenomena for Laser Full Penetration Welding

Hongbo Zhao,Huan Qi 대한용접·접합학회 2017 대한용접·접합학회지 Vol.35 No.2

In laser full penetration welding process, full penetration hole(FPH) is formed as a result of force balance between the vapor pressure and the surface tension of the surrounding molten metal. In this work, a three-dimensional numerical model based on a conserved-mass level-set method is developed to simulate the transport phenomena during laser full penetration welding process, including full penetration keyhole dynamics. Ray trancing model is applied to simulate multi-reflection phenomena in the keyhole wall. The ghost fluid method and continuum method are used to deal with liquid/vapor interface and solid/liquid interface. The effects of processing parameters including laser power and scanning speed on the resultant full penetration hole diameter, laser energy distribution and energy absorption efficiency are studied. The model is validated against experimental results. The diameter of full penetration hole calculated by the simulation model agrees well with the coaxial images captured during laser welding of thin stainless steel plates. Numerical simulation results show that increase of laser power and decrease of welding speed can enlarge the full penetration hole, which decreases laser energy efficiency.

Investigations on Influence of Erection Process on Buckling of Large Span Structures by a Novel Numerical Method

Zhongwei Zhao,Zhi-Hua Chen,Hongbo Liu,Bingzhen Zhao 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.3

The erection process of long-span spatial structures is significantly nonlinear which is often accompanied by variations in boundary condition and material property. Many researchers have conducted investigations on construction simulation of complex structures. But few investigate influence of erection process on buckling behavior of structures in service. A method for estimating the influence was proposed. The reliability and accuracy of this method was validated. Then three kinds of structures were analyzed to estimate influence of erection process. The results indicate that some kinds of structures are sensitive to erection process. Influence of erection process on buckling capacity should be considered appropriately.

Analysis and comparison of the 2D/1D and quasi-3D methods with the direct transport code SHARK

Chen Zhao,Xingjie Peng,Hongbo Zhang,Wenbo Zhao,Qing Li,Zhang Chen 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.1

The 2D/1D method has become the mainstream of the direct transport calculation considering the balance of accuracy and efficiency. However, the 2D/1D method still suffers from stability issues. Recently, a quasi-3D method has been proposed with axial Legendre expansion. Analysis and comparison of the 2D/1D and quasi-3D method is conducted in theory from the equation derivation. Besides, the C5G7 benchmark, the KUCA benchmark and the macro BEAVRS benchmark are calculated to verify the theory comparisons of these two methods with the direct transport code SHARK. All results show that the quasi-3D method has better stability and accuracy than the 2D/1D method with worse efficiency and memory cost. It provides a new option for direct transport calculation with the quasi-3D method.

Research on the Influence of Inter-turn Short Circuit Fault on the Temperature Field of Permanent Magnet Synchronous Motor

Hongbo Qiu,Wenfei Yu,Bingxia Tang,Cunxiang Yang,Haiyang Zhao 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.4

When the inter-turn short circuit (ITSC) fault occurs, the distortion of the magnetic field is serious. The motor loss variations of each part are obvious, and the motor temperature field is also affected. In order to obtain the influence of the ITSC fault on the motor temperature distribution, firstly, the normal and the fault finite element models of the permanent magnet synchronous motor (PMSM) were established. The magnetic density distribution and the eddy current density distribution were analyzed, and the mechanism of loss change was revealed. The effects of different forms and degrees of the fault on the loss were obtained. Based on the loss analysis, the motor temperature field calculation model was established, and the motor temperature change considering the loop current was analyzed. The influence of the fault on the motor temperature distribution was revealed. The sensitivity factors that limit the motor continuous operation were obtained. Finally, the correctness of the simulation was verified by experiments. The conclusions obtained are of great significance for the fault and high temperature demagnetization of the permanent magnet analysis.

Active DC-Link Power Filter for Single Phase PWM Rectifiers

Hongbo Li,Kai Zhang,Hui Zhao 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

Single-phase PWM rectifier produces second-order ripple power and voltage pulsation on DC side, which is harmful to both the grid and load. The pulsating power is usually absorbed by a bulky capacitor bank and/or a dedicative LC resonant link, which results in low power density. An alternative way to do this is using some active filter circuit to direct the pulsating power to an energy-storage component. As a result, the main DC link capacitor can be reduced substantially. Based on a comparison of DC-link active power filter (APF) schemes, this paper chooses a simple but effective half-bridge topology, and proposed a control strategy based on dual-loop deadbeat control plus repetitive control. This topology with the proposed control strategy can effectively reduce the voltage pulsation on DC bus and improve the power density of the rectifier.