Cyclic response and design procedure of a weak-axis cover-plate moment connection

Linfeng Lu,Yinglu Xu,Huixiao Zheng,James B.P. Lim 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.26 No.3

This paper systematically investigated the mechanical performance of the weak-axis cover-plate connection, including a beam end monotonic loading test and a column top cyclic loading test, and a series of parametric studies for exterior and interior joints under cyclic loading using a nonlinear finite element analysis program ABAQUS, focusing on the influences of the shape of top cover-plate, the length and thickness of the cover-plate, the thickness of the skin plate, and the steel material grade. Results showed that the strains at both edges of the beam flange were greater than the middle's, thus it is necessary to take some technical methods to ensure the construction quality of the beam flange groove weld. The plastic rotation of the exterior joint can satisfy the requirement of FEMA-267 (1995) of 0.03 rad, while only one side connection of interior joint satisfied ANSI/AISC 341-10 under the column top cyclic loading. Changing the shape or the thickness or the length of the cover-plate did not significantly affect the mechanical behaviors of frame joints no matter in exterior joints or interior joints. The length and thickness of the cover-plate recommended by FEMA 267 (1995) is also suitable to the weak-axis cover-plate joint. The minimum skin plate thickness and a design procedure for the weak-axis cover-plate connections were proposed finally.

Investigation of Composite Action on Seismic Performance of Weak-axis Column-tree Moment Connections

Yinglu Xu,Linfeng Lu,Hong Zheng 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.3

This paper presents an experimental study on a developed weak-axis column-tree moment connection subjected to horizontal cyclic loading. In order to study possible positive or negative effect of a composite slab on the seismic performance of the proposed connection, six cruciform specimens were designed and constructed in pairs, where one specimen was bare steel joint and the other involved a composite slab. The standard, cover-plate, and material-changed connection details were considered. The test program is described in detail, and then the structural behavior of test specimens is discussed based on the test data. The tests revealed that although designed with 50% degree of shear connection, the concrete slab still caused obvious upward shift of the neutral axis and increase the strain demand on the bottom flange. But it is clear from the comparison of results that the composite joint specimens performed slightly better than the bare steel counterparts in terms of load-displacement hysteretic curves and energy dissipation capacity, as the concrete slab could effectively enhance the stability of the steel beam and delay the deterioration of the strength and stiffness. The cover-plate connection appears to be one of the more promising moment connection schemes which are able to deliver a much higher level of stability and energy dissipation capacity. The maximum magnitude of slab-steel beam interface slip was less than 0.5 mm, indicating that the concrete floor slab and steel beam could work well together under 50% partial shear connection.

Security Analysis of the PHOTON Lightweight Cryptosystem in the Wireless Body Area Network

( Wei Li ),( Linfeng Liao ),( Dawu Gu ),( Chenyu Ge ),( Zhiyong Gao ),( Zhihong Zhou ),( Zheng Guo ),( Ya Liu ),( Zhiqiang Liu ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.1

With the advancement and deployment of wireless communication techniques, wireless body area network (WBAN) has emerged as a promising approach for e-healthcare that collects the data of vital body parameters and movements for sensing and communicating wearable or implantable healthful related information. In order to avoid any possible rancorous attacks and resource abuse, employing lightweight ciphers is most effective to implement encryption, decryption, message authentication and digital signature for security of WBAN. As a typical lightweight cryptosystem with an extended sponge function framework, the PHOTON family is flexible to provide security for the RFID and other highly-constrained devices. In this paper, we propose a differential fault analysis to break three flavors of the PHOTON family successfully. The mathematical analysis and simulating experimental results show that 33, 69 and 86 random faults in average are required to recover each message input for PHOTON-80 /20/16, PHOTON-160/36/36 and PHOTON-224/32/32, respectively. It is the first result of breaking PHOTON with the differential fault analysis. It provides a new reference for the security analysis of the same structure of the lightweight hash functions in the WBAN.

Finite Element Analysis of Weak-Axis Composite Connections Under Cyclic Loading

Yinglu Xu,Linfeng Lu,Hong Zheng 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.1

This paper describes a numerical study on weak-axis composite connection through the nonlinear fi nite element program ABAQUS. After the simulation and validation of experimental results, a total of 16 models were created to investigate the infl uence of the diff erent parameters on the structural performance, and their hysteresis responses, rupture index distribution of beam fl ange welds were discussed in detail. The RBS connection scheme could develop extensive inelastic deformation in RBS region, thus reducing the weld rupture possibility. The thicker the concrete slab, the larger the bending moment under positive bending, and the higher the RI values at the beam bottom fl ange weld and also the neutral axis. The structural behavior was insensitive to the variation of the parameter reinforcement ratio as the reinforcements did not work well, and it is recommended to arrange reinforcements according to the construction requirements. Changing the weld access hole form has a little infl uence on the bearing capacity and rotation capacity, but the PEEQ and RI distributions are sensitive to this parameter. The design option of long access holes could provide a further means to reduce the fracture possibility of beam fl ange groove weld to a reasonable level, thus achieving a favorable performance of weak-axis column bending connections in a composite moment-resisting frame.

Parametric Study of Weak-Axis Beam-to-Column Composite Connections with Asymmetrical Reduced Beam Section

Yinglu Xu,Linfeng Lu,Hong Zheng 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.2

To evaluate the eff ectiveness of the asymmetrical steel beam section and reduced beam section (RBS), this paper presents a parametric study on weak-axis beam-to-column composite connections with asymmetrical reduced beam section subjected to horizontal cyclic loading. After validating the accuracy of the fi nite element modeling through comparing to the experimental results, a total of 29 refi ned tridimensional models for four series were created for parametric analysis. The load–displacement and moment–rotation relationships, the Mises index, triaxiality index and rupture index distribution across the width of the fl ange welds for each connection were reported. A smaller steel beam top and bottom fl ange width ratio α could alleviate the adverse eff ect of the composite action. The parametric analysis about the geometrical variables of RBS confi rms the need for readjustment of the geometrical characteristics of the RBS in order to apply to the proposed weak-axis profi les. For design purposes, the parameter a , the distance from the skin plate to the reduced region, can be set to (0.65–0.9) b bf ; the parameter b , the length of the reduced region, can be set to b = (0.65–0.90) d b ; the parameter c , the maximum reduction depth of beam bottom fl ange, can be set to 0.20 b bf , where b bf and d b are the beam bottom fl ange width and beam depth respectively.

Glasgow prognostic score and combined positive score for locally advanced rectal cancer

Yanru Feng,Jialin Luo,Peng Liu,Luying Liu,Yuan Zhu,Guoping Cheng,Linfeng Zheng 대한외과학회 2022 Annals of Surgical Treatment and Research(ASRT) Vol.102 No.3

Purpose: This study was performed to investigate the association of Glasgow prognostic score (GPS), combined positive score (CPS), and clinicopathological characteristics of locally advanced rectal cancer. Methods: Between February 2012 and February 2018, 103 patients with locally advanced rectal cancer treated by neoadjuvant chemoradiotherapy and total mesorectal excision (TME) were retrospectively evaluated. Results: According to the classification of the GPS, 85 (82.5%), 13 (12.6%), and 5 patients (4.9%) were classified as a score of 0, 1, and 2, respectively. Patients were classified into the GPS-low group (GPS of 0, n = 85) and GPS-high group (GPS of 1 or 2, n = 18) with an area under the curve of 0.582 for overall survival (OS). The mean programmed death-ligand 1 (PD-L1) CPS of the whole group was 2.24 (range, 0–70). The PD-L1 CPS of the GPS-high group was higher than the GPS-low group (P < 0.001). Multivariate analysis by Cox proportional hazards model indicated that GPS was associated with OS and disease- free survival (DFS). Furthermore, PD-L1 CPS was associated with DFS (hazard ratio, 1.050; 95% confidence interval, 1.017– 1.083; P = 0.003). Conclusion: Elevated GPS was related to the PD-L1 CPS. GPS and PD-L1 CPS were associated with the prognosis of locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy followed by TME.