Dynamic increase factor for progressive collapse of semi-rigid steel frames with extended endplate connection

Ying Huang,Yan Wu,Changhong Chen,Zhaohui Huang,Yao Yao 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.31 No.6

As an extremely destructive accident, progressive collapse is defined as the spread of an initial local failure from element to element, resulting eventually in the collapse of an entire structure or disproportionately large of it. To prevent the occurrence of it and evaluate the ability of structure resisting progressive collapse, the nonlinear static procedure is usually adopted in the whole structure design process, which considered dynamic effect by utilizing Dynamic Increase Factor (DIF). In current researches, the determining of DIF is performed in full-rigid frame, however, the performance of beam-column connection in the majority of existing frame structures is not full-rigid. In this study, based on the component method proposed by EC3 guideline, the expression of extended endplate connection performance is further derived, and the connection performance is taken into consideration when evaluated the performance of structure resisting progressive collapse by applying the revised plastic P-M hinge. The DIF for structures with extended endplate beam-column connection have been determined and compared with the DIF permitted in current GSA guideline, the necessity of considering connection stiffness in determining the DIF have been proved.

A High Efficiency and Low Carbon Oriented Machining Process Route Optimization Model and Its Application

Zhaohui Deng,Lishu Lv,Wenliang Huang,Yangdong Shi 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.6 No.1

This paper aims to reduce the carbon emission of the manufacturing process and to achieve the low carbon optimization decision of the machining process route. Carbon emission was analyzed from the perspective of material flow, energy flow and environmental flow, and the machining process route carbon efficiency model was established based on the one from per unit cutted-volume. A multi-objective machining process route optimization model was established based on the genetic algorithms (GA), and the minimum processing time (high efficiency) and the optimal carbon efficiency (low carbon) were set as the optimization objectives. An experiment case study was performed on grinding carriage box, and a comparison was given between the optimized process and traditional process. The results indicate the resultant process route from the proposed algorithm, which verifies to reduce the processing time and increase the carbon efficiency.

Exponential L₂-L∞ Filtering for a Class of Stochastic System with Markovian Jump Parameters and Mixed Mode-Dependent Time-Delays

Zhaohui Chen,Qi Huang 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.3

This paper discusses the exponential L₂-L∞ filtering problem of a class of nonlinear stochastic systems with Markovian jumping parameters and mixed mode-dependent time-varying delays. By introducing a new multiple mode-dependent Lyapunov-Krasovskii functional, stochastic analysis is conducted. The condition for the existence of mode-dependent L₂-L∞ filter, in which the filtering error is guaranteed to be exponentially stable with prescribed L₂-L∞ performance, is developed. The developed criterion is delay-range-dependent, mode-dependent and decay-rate-dependent. Based on the derived criterion, the L₂-L∞ filtering problems are solved. The mode-dependent filter coefficients can be obtained by solving a set of linear matrix inequalities (LMIs). Numerical simulations are presented to illustrate the effectiveness of the proposed approach.

Experiment research on grind-hardening of AISI5140 steel based on thermal compensation

Xiangming Huang,Yinghui Ren,Bo Zheng,Zhaohui Deng 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.8

The grind-hardening process utilizes the heat generated to induce martensitic phase transformation. However, the maximum achievable harden layer depth is limited due to high grinding forces, and the tensile residual stress appears on the ground surface in the grindhardening process. This paper proposes a new grind-hardening technology using thermal compensation. The workpiece of AISI5140 steel is preheated by electric resistance heating, and ground under the condition of the workpiece temperature 25°C, 120°C, 180°C and 240°C. The grinding force, harden layer depth and surface quality including residual stress on ground surface, surface roughness and micro-hardness are investigated. The experimental results show that a deep harden layer with a fine grain martensite can be obtained with the thermal compensation. The ground workpiece surface produces a certain compressive residual stress, and the residual compressive stress value increases with preheating temperature. As the preheating temperature increases, grinding force slightly decreases, while there is slightly increment of surface roughness. Compared with the conventional grind-hardening process, both the harden layer depth and residual stress distribution are significantly improved.

Analysis of end-plate connections at elevated temperatures

Shuyuan Lin,Zhaohui Huang,Mizi Fan 국제구조공학회 2013 Steel and Composite Structures, An International J Vol.15 No.1

In this paper a robust 2-noded connection element has been developed for modelling the bolted end-plate connection between steel beam and column at elevated temperatures. The numerical procedure described is based on the model proposed by Huang (2011), incorporating additional developments to more precisely determinate the tension, compression and bending moment capacities of end-plate connection in fire. The proper failure criteria are proposed to calculate the tension capacity for each individual bolt row. In this new model the connection failure due to bending, axial tension, compression and shear are considered. The influence of the axial force of the connected beam on the connection is also taken into account. This new model has the advantages of both the simple and component-based models. In order to validate the model a total of 22 tests are used. It is evident that this new connection model has ability to accurately predict the behaviour of the end-plate connection at elevated temperatures, and can be used to represent the end-plate connections in supporting performance-based fire resistance design of steel-framed composite buildings.

An incompatible 3D solid element for structural analysis at elevated temperatures

Xinmeng Yu,Xiaoxiong Zha,Zhaohui Huang 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.3

The eight-node 3D solid element is one of the most extensively used elements in computational mechanics. This is due to its simple shape and easy of discretization. However, due to the parasitic shear locking, it should not be used to simulate the behaviour of structural members in bending dominant conditions. Previous researches have indicated that the introduction of incompatible mode into the displacement field of the solid element could significantly reduce the shear locking phenomenon. In this study, an incompatible mode eight-node solid element, which considers both geometric and material nonlinearities, is developed for modelling of structural members at elevated temperatures. An algorithm is developed to extend the state determination procedure at ambient temperature to elevated temperatures overcoming initially converged stress locking when the external load is kept constant. Numerical studies show that this incompatible element is superior in terms of convergence, mesh insensitivity and reducing shear locking. It is also showed that the solid element model developed in this paper can be used to model structural behaviour at both ambient and elevated temperatures.

An incompatible 3D solid element for structural analysis at elevated temperatures

Yu, Xinmeng,Zha, Xiaoxiong,Huang, Zhaohui Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.3

The eight-node 3D solid element is one of the most extensively used elements in computational mechanics. This is due to its simple shape and easy of discretization. However, due to the parasitic shear locking, it should not be used to simulate the behaviour of structural members in bending dominant conditions. Previous researches have indicated that the introduction of incompatible mode into the displacement field of the solid element could significantly reduce the shear locking phenomenon. In this study, an incompatible mode eight-node solid element, which considers both geometric and material nonlinearities, is developed for modelling of structural members at elevated temperatures. An algorithm is developed to extend the state determination procedure at ambient temperature to elevated temperatures overcoming initially converged stress locking when the external load is kept constant. Numerical studies show that this incompatible element is superior in terms of convergence, mesh insensitivity and reducing shear locking. It is also showed that the solid element model developed in this paper can be used to model structural behaviour at both ambient and elevated temperatures.

Screening nephroprotective compounds from cortex Moutan by mesangial cell extraction and UPLC

Min Sun,Limei Huang,Jianliang Zhu,Wenjie Bu,Jing Sun,Zhaohui Fang 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.6

A method for screening nephroprotective compoundsin cortex Moutan, a common traditional Chinesemedicine (TCM) in treating diabetic nephropathy with renalmesangial cell extraction and ultra performance liquidchromatography technique was described in this paper. Wehypothesize that the compounds which bind to cell membranesunder pathological conditions may be the bioactivecompounds in TCMs. Mesangial cells were cultured inmedium containing 5 mM (physiological, NG) or 30 mM(pathological, HG) glucose for 48 h and then incubated withcortex Moutan extract. After the unbound substances werewashed off, the cell membrane-bound compounds weredissociated and concentrated by an SPE column. By comparingthe chromatograms of NG and HG cultured-cellextractions and cortex Moutan extract, three compoundsbound to both NG and HG-cultured mesangial cells wereidentified as paeoniflorin, pentagalloylglucose (PGG) andpaeonol. In vitro studies showed that paeoniflorin, PGG andpaeonol reduced the activity of nicotinamide-adenine dinucleotidephosphate oxidase (NADPH) activity, anddecreased the level of reactive oxygen species (ROS),transforming growth factor-b1 (TGF-b1) and fibronectin inhigh glucose cultured mesangial cells. The results indicatethat paeonol, paeoniflorin and PGG may be the nephroprotectivecompounds from cortex Moutan. This study isexpected to provide a more reliable and effective method forscreening bioactive compounds from the complex TCM systems.

Prevalence and risk factors for incidental prostate cancer in patients after transurethral resection of the prostate with negative results on prostate biopsy: A retrospective study

Zhenlang Guo,Junwei He,Jun Pan,Lijuan Huang,Jiadong Cao,Zunguang Bai,Shusheng Wang,Songtao Xiang,Chiming Gu,Zhaohui Wang 대한비뇨의학회 2022 Investigative and Clinical Urology Vol.63 No.2

Purpose: This study aimed to explore the prevalence and predictors of incidental prostate cancer (IPC) after transurethral resection of the prostate (TURP) with negative results on transperineal magnetic resonance imaging (MRI)/transrectal ultrasonography (TRUS) fusion prostate biopsy or TRUS-guided prostate biopsy. Materials and Methods: Data of 253 patients who underwent TURP with a preliminary diagnosis of benign prostatic hyperplasia (BPH) were evaluated. The prevalence of IPC was calculated. Univariate and multivariate logistic regression analyses were conducted to explore independent predictive factors of IPC. Results: A total of 253 patients were included. IPC was diagnosed in 12 patients (4.7%). The mean age of the patients and the mean prostate volume were 69.8±7.07 years and 89.3±49.29 mL, respectively. The prevalence of IPC was higher in the TRUS guided prostate biopsy group than in the transperineal MRI/TRUS fusion prostate biopsy group (11 of 203 [5.4%] vs. 1 of 50 [2.0%], p=0.47), but the difference was not statistically significant. Our results indicated that older age (≥70 y) (odds ratio [OR], 1.14; 95% confidence interval [CI], 1.02–1.27; p=0.025) and smaller prostate volume (OR, 0.97; 95% CI, 0.938–0.998; p=0.039) were associated with an increased incidence of IPC after TURP. Conclusions: Our findings indicate that the prevalence of IPC may be higher among patients who undergo transrectal prostate biopsy before TURP than among those who undergo transperineal MRI/TRUS fusion prostate biopsy. Older age and smaller prostate volume were independent predictors of increasing the risk for IPC after TURP.

A simple electrospinning strategy to achieve the uniform distribution of ultra‑fine CoP nanocrystals on carbon nanofibers for efficient lithium storage

Qinghua Wang,Wei Wang,Junlin Huang,Hong Yin,Yucan Zhu,Haitao Wang,Minjie Zhou,Binhong He,Zhaohui Hou,Wenyuan Xu 한국탄소학회 2023 Carbon Letters Vol.33 No.1

Transition-metal phosphides (TMPs), a promising anode material for lithium-ion batteries (LIBs), are limited in application because of its serious volume effect in the cycle. In this work, a simple electrospinning strategy was proposed to restrict the grain size of CoP nanocrystals by nano-confined effect of carbon nanofibers with ligands. The addition of ligands not only could realize the uniform dispersion of CoP nanocrystals, but also strengthen the bond between the metals and carbon nanofibers. As a result, the CoP/CNF composite exhibits excellent lithium storage performance, and its reversible specific capacity could reach 1016.4 mAh g? 1 after 200 cycles at a current density of 200 mA g? 1. The research is anticipated to provide a new idea for the preparation of anode materials for lithium ion batteries.