A novel design method for improving collapse resistances of multi-story steel frames with unequal spans using steel braces

Zheng Tan,Wei-hui Zhong,Bao Meng,Shi-chao Duan,Hong-chen Wang3,Xing-You Yao,Yu-hui Zheng 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.47 No.2

The bearing capacities resisted by the two-bay beams of multi-story planar frames with unequal spans under column removal scenarios differ considerably owing to the asymmetric stress on the left and right beams connected to the failed column and cause the potential for beams with larger span-to-depth ratios to be unable to exert effectively, which is disadvantageous for resisting the vertical load in unequal-span frame structures. To address this problem, the structural measure of adding braces to the weak bays of multi-story unequal-span frames was proposed, with the objective of achieving a coordinated stress state in two-bay beams with unequal spans, thereby improving the collapse resistance of unequal-span frame structures. Before conducting the numerical simulation, the modeling methods were verified by previous experimental results of two multi-story planar frames with and without steel braces. Thereafter, the effects of the tensile and compressive braces on the collapse behavior of the frame structures were elucidated. Then, based on the mechanical action laws of the braces throughout the collapse process, a detailed design method for improving the collapse resistance of unequal-span frame structures was proposed. Finally, the proposed design method was verified by using sufficient example models, and the results demonstrated that the design method has good application prospects and high practical value.

Inhibition of Microcystis aeruginosa by the Extracellular Substances from an Aeromonas sp

( Yu Mei Liu ),( Ming Jun Chen ),( Meng Hui Wang1 ),( Rui Bao Jia ),( Li Li ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.9

Growth of Microcystis aeruginosa could be inhibited significantly within 24 h by the extracellular substances prepared from Aeromonas sp. strain FM. During the treatment, the concentration of extracellular soluble carbohydrates increased significantly in algal culture. Morphological and ultrastructural changes in M. aeruginosa cells, including breakage of the cell surface, secretion of mucilage, and intracellular disorganization of thylakoids, were observed. HPLC-MS analysis showed that the extracellular substances of Aeromonas sp. strain FM were a mixture of free amino acids, tripeptides, and clavulanate. Among these, the algaelysis effects of lysine and clavulanate were confirmed.

Tractive performance evaluation of seafloor tracked trencher based on laboratory mechanical measurements

Wang, Meng,Wang, Xuyang,Sun, Yuanhong,Gu, Zhimin The Society of Naval Architects of Korea 2016 International Journal of Naval Architecture and Oc Vol.8 No.2

To evaluate the tractive performance of tracked trencher on seafloor surface, a new shear stress-displacement empirical model was proposed for saturated soft-plastic soil (SSP model). To validate the SSP model, a test platform, where track segment shear test can be performed in seafloor soil simulacrum (bentonite water mixture), was built. Series shear tests were carried out. Test results indicate that the SSP model can describe the mechanical behavior of track segment with good approximation in seafloor soil simulacrum. Through analyzing the main external forces applied to seafloor tracked trencher during the uniform linear trenching process, a drawbar pull prediction model was deduced with the SSP model. A tracked walking mechanism of the seafloor tracked trencher prototype was built, and verification tests were carried out. Test results indicate that this prediction model was feasible and effective; moreover, from another side, this conclusion also proved that the SSP model was effective.

Influencing Factors Analysis of Degradation and Damage and the Effect on Steel Frame

Meng Wang,Yong-Jiu Shi,Yuan-Qing Wang,Wei Guo Yang 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.1

In order to discuss the influencing factors of damage and degradation and the effect on steel frame subject to strongearthquakes, firstly, a constitutive model was proposed for 3D finite element models to calculate the seismic behaviors of steelframe more accurately. The model was proved correct and applicable due to typical quasi-static tests. Then, based on theverified model, the damage and degradation factors were discussed by parametric analyses, including the panel zone, loadinghistory, loading amplitude, the width to thickness ratio and yield strength. The cumulative damage phenomena of steel frameconnections were further studied and the degradation distribution curve was obtained. Finally, the traditional beam elementmodel and proposed shell element model of structure were established by ABAQUS for time history analysis. The effect ofdamage and degradation on seismic behaviors of steel frames were compared and discussed. The tests and analysis resultsrevealed that: panel zone strength, loading amplitude and width-thickness ratios of plates had significant impact on damage anddegradation behaviors and failure modes of connections. Premature weld cracking would lead to earlier damage and degradationunder “strong to weak” earthquake, which would seriously affect the overall mechanical properties of the structure. Once localbuckling caused damage, the results of the beam element model and accurate shell element model were remarkably different. Beam element model without considering damage and degradation underestimated the structural deformations, which shouldbe paid more attention for design safety.

Prognostic Analysis of Schistosomal Rectal Cancer

Wang, Meng,Zhang, Yuan-Chuan,Yang, Xu-Yang,Wang, Zi-Qiang Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.21

Background: Schistosomiasis is an infectious disease that affects more than 230 million people worldwide, according to conservative estimates. Some studies published from China and Japan reported that schistosomiasis is a risk factor for colorectal cancer in Asia where the infective species is S. japonicum. Hoqwever, there have been only few reports of prognosis of patients with schistosomal rectal cancer SRC. Objectives: This study aimed to analyze differences in prognosis between SRC and non-schistosomal rectal cancer(NSRC) with current treatments. Materials and Methods: A retrospective review of 30 patients with schistosomal rectal cancer who underwent laparoscopic total mesorectal excision operation (TME) was performed. For each patient with schistosomal rectal cancer, a control group who underwent laparoscopic TME with non-schistosomal rectal cancer was matched for age, gender and tumor stage, resulting in 60 cases and controls. Results: Univariate analysis showed pathologic N stage (P=0.006) and pathologic TNM stage (P=0.047) statistically significantly correlated with disease-free survival (DFS). Pathologic N stage (P=0.014), pathologic TNM stage (P=0.002), and with/without schistosomiasis (P=0.026) were statistically significantly correlated with overall survival (OS). Schistosomiasis was the only independent prognostic factor for DFS and OS in multivariate analysis. Conclusions: The prognosis of patients with schistosomal rectal cancer is poorer than with non-schistosomal rectal cancer.

Strongly Enhanced Electric Field Outside a Pit from Combined Nanostructure of Inverted Pyramidal Pits and Nanoparticles

Meng Wang,Wudeng Wang 한국광학회 2023 Current Optics and Photonics Vol.7 No.5

We designed a combined nanostructure of inverted pyramidal pits and nanoparticles, which can obtain much stronger field enhancement than traditional periodic pits or nanoparticles. The field enhancement |E|/|E 0 | is greater than 10 in a large area at 750–820 nm in incident wavelength. |E max |/|E 0 | is greater than 60. Moreover, the hot spot is obtained outside the pits instead of localized inside them, which is beneficial for experiments such as surface-enhanced Raman scattering. The relations between resonant wavelength and structural parameters are investigated. The resonant wavelength shows a linear dependence on the structure’s period, which provides a direct way to tune the resonant wavelength. The excitation of a propagating surface plasmon on the periodic structure’s surface, a localized surface plasmon of nanoparticles, and a standing-wave effect contribute to the enhancement.

Prognostic Significance of the Mucin Component in Stage III Rectal Carcinoma Patients

Wang, Meng,Zhang, Yuan-Chuan,Yang, Xu-Yang,Wang, Zi-Qiang Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.19

Background: Although mucinous adenocarcinoma has been recognized for a long time, whether it is associated with a poorer prognosis in colorectal cancer patients is still controversial. Many studies put emphasis on mucinous adenocarcinoma containing mucin component ${\geq}50%$. Only a few studies have analyzed cases with a mucin component <50%. Objectives: This study aimed to analyze the prognostic value of different mucin component proportions in patients with stage III rectal cancer. Materials and Methods: Clinical, pathological and follow-up data of 136 patients with the stage III rectal cancer were collected. Every variable was analyzed by univariate analysis, then multivariate analysis and survival analysis were further performed. Results: Univariate analysis showed pathologic T stage, lymphovascular invasion, and histological subtype were statistically significant for DFS. Pathologic T stage was significant for OS. Histological subtype and lymphovascular invasion were independent prognostic factors in multivariate analysis for DFS, and histological subtype was the only independent prognostic factor for OS. Survival curves showed the survival time of mucinous adenocarcinoma (MUC) was shorter than non-MUC (adenocarcinomas with a mucin component <50% and without mucin component). Conclusions: Histological subtype (tumor with different mucin component) was an independent prognostic factor for both DFS and OS. Patients with MUC had a worse prognosis than their non-MUC counterparts with stage III rectal carcinoma.

Estimation for the Random Errors of Reflector Surfaces Using Measured Data

Meng Wang,Cong-Si Wang,Wei Wang,Jin-Zhu Zhou,Peng Li 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

In this research, a novel error-decomposition scheme is developed to determine efficiently the random errors of reflector surface basedon the discrete measurement data. The least squares fitting of semi-closed B-spline surface is employed. Subsequently, a spatialstatistical analysis is performed to determine whether the spatial independent distribution of the sampled data points is attained fora given confidence level. This research rests on the assumption that the measurement errors of instruments are trivial compared withrandom errors caused by machining and assembly inaccuracies. The presented methodology has been applied to the surface analysisof a 3.7 m reflector antenna.

Tractive performance evaluation of seafloor tracked trencher based on laboratory mechanical measurements

Meng Wang,Xuyang Wang,Yuanhong Sun,Zhimin Gu 대한조선학회 2016 International Journal of Naval Architecture and Oc Vol.8 No.2

To evaluate the tractive performance of tracked trencher on seafloor surface, a new shear stress-displacement empirical model was proposed for saturated soft-plastic soil (SSP model). To validate the SSP model, a test platform, where track segment shear test can be performed in seafloor soil simulacrum (bentonite water mixture), was built. Series shear tests were carried out. Test results indicate that the SSP model can describe the mechanical behavior of track segment with good approximation in seafloor soil simulacrum. Through analyzing the main external forces applied to seafloor tracked trencher during the uniform linear trenching process, a drawbar pull prediction model was deduced with the SSP model. A tracked walking mechanism of the seafloor tracked trencher prototype was built, and verification tests were carried out. Test results indicate that this prediction model was feasible and effective; moreover, from another side, this conclusion also proved that the SSP model was effective.

Application of steel equivalent constitutive model for predicting seismic behavior of steel frame

Meng Wang,Yongjiu Shi,Yuanqing Wang 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.5

In order to investigate the accuracy and applicability of steel equivalent constitutive model, the calculated results were compared with typical tests of steel frames under static and dynamic loading patterns firstly. Secondly, four widely used models for time history analysis of steel frames were compared to discuss the applicability and efficiency of different methods, including shell element model, multi-scale model, equivalent constitutive model (ECM) and traditional beam element model (especially bilinear model). Four-story steel frame models of above-mentioned finite element methods were established. The structural deformation, failure modes and the computational efficiency of different models were compared. Finally, the equivalent constitutive model was applied in seismic incremental dynamic analysis of a ten-floor steel frame and compared with the cyclic hardening model without considering damage and degradation. Meanwhile, the effects of damage and degradation on the seismic performance of steel frame were discussed in depth. The analysis results showed that: damages would lead to larger deformations. Therefore, when the calculated results of steel structures subjected to rare earthquake without considering damage were close to the collapse limit, the actual story drift of structure might already exceed the limit, leading to a certain security risk. ECM could simulate the damage and degradation behaviors of steel structures more accurately, and improve the calculation accuracy of traditional beam element model with acceptable computational efficiency.