Block Tearing and Local Buckling of Aluminum Alloy Gusset Joint Plates

Xiaonong Guo,Zhe Xiong,Yongfeng Luo,Han Xu,Shuiping Liang 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.2

Aluminum Alloy Gusset (AAG) joints widely used in the single-layer latticed shells have a significant application prospect in spatial structures. Unfortunately, studies on the resistance of AAG joints are insufficient, leading to a lack of applicative design methods for this joint system. This paper is devoted to investigate the resistance of AAG joint plates. Firstly, tests on fourteen AAG joint specimens are carried out to explore their collapse modes. Experimental phenomena show that the main collapse modes of AAG joint plates include the block tearing of top plates and the local buckling of bottom plates. Secondly, Finite Element (FE) simulations to investigate the mechanical behavior of AAG joints are performed by means of the non-linear FE code ABAQUS. Thirdly, formulae for predicting the block tearing resistance and the local buckling resistance of AAG joint plates are proposed, which are based on theoretical analyses. Fourthly, test results are of great help in the determination of parameters k and α which are adopted to modify the block tearing resistance and the local buckling resistance respectively. Finally, a comparison of test results verifies that theoretical formulae are applicable. In addition, in order to avoid the block tearing and the local buckling of AAG joint plates, convenient design criteria are provided.

Experimental studies on behaviour of bolted ball-cylinder joints under axial force

Xiaonong Guo,Zewei Huang,Zhe Xiong,Shangfei Yang,Li Peng 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.1

Due to excellent advantages such as better illuminative effects, considerable material savings and ease and rapidness of construction, the bolted ball-cylinder joint which is a new type joint system has been proposed in space truss structures. In order to reveal more information and understanding on the behaviour of bolted ball-cylinder joints, full-scale experiments on eight bolted ball-cylinder joint specimens were conducted. Five joint specimens were subjected to axial compressive force, while another three joint specimens were subjected to axial tensile force. The parameters investigated herein were the outside diameter of hollow cylinders, the height of hollow cylinders, the thickness of hollow cylinders, ribbed stiffener and axial force. These joint specimens were collapsed by excessive deformation of hollow cylinders, punching damage of hollow cylinders, evulsion of bolts, and weld cracking. The strain distributions on the hollow cylinder opening were mainly controlled by bending moments. To improve the ultimate bearing capacity and axial stiffness of bolted ball-cylinder joints, two effective measures were developed: (1) the thickness of the hollow cylinder needed to be thicker; (2) the ribbed stiffener should be adopted. In addition, the axial stiffness of bolted ball-cylinder joints exhibited significant non-linear characteristics.

Numerical studies on behaviour of bolted ball-cylinder joint under axial force

Xiaonong Guo,Zewei Huang,Zhe Xiong,Shangfei Yang,Li Peng 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.20 No.6

This paper presents the results of an extensive numerical analysis program devoted to the investigation of the mechanical behaviour of bolted ball-cylinder joints. The analysis program is developed by means of finite element (FE) models implemented in the non-linear code ABAQUS. The FE models have been accurately calibrated on the basis of available experimental results. It is indicated that the FE models could be used effectively to describe the mechanical performance of bolted ball-cylinder joints, including failure modes, stress distributions and loaddisplacement curves. Therefore, the proposed FE models could be regarded as an efficient and accurate tool to investigate the mechanical behavior of bolted ball-cylinder joints. In addition, to develop a further investigation, parametric studies were performed, varying the dimensions of hollow cylinders, rectangular tubes, convex washers and ribbed stiffener. It is found that the dimensions of hollow cylinders, rectangular tubes and ribbed stiffener influenced the mechanical behaviour of bolted ball-cylinder joints significantly. On the contrary, the effects of the dimensions of convex washers were negligible.

Experimental studies on behaviour of tubular T-joints reinforced with grouted sleeve

Shou-Chao Jiang,Xiaonong Guo,Zhe Xiong,Yufang Cai,Shaojun Zhu 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.23 No.5

Tubular joints have been widely used in offshore platforms and space structures due to their merits such as easy fabrication, aesthetic appearance and better static strength. For existing tubular joints, a grouted sleeve reinforced method was proposed in this paper. Experimental tests on five tubular T-joints reinforced with the grouted sleeve and two conventional tubular T-joints were conducted to investigate their mechanical behaviour. A constant axial compressive force was applied to the chord end to simulate the compressive state of the chord member during the tests. Then an axial compressive force was applied to the top end of the brace member until the collapse of the joint specimens occurred. The parameters investigated herein were the grout thickness, the sleeve length coefficient and the sleeve construction method. The failure mode, ultimate load, initial stiffness and deformability of these joint specimens were discussed. It was found that: (1) The grouted sleeve could change the failure mode of tubular T-joints. (2) The grouted sleeve was observed to provide strength enhancement up to 154.3%~172.7% for the corresponding un-reinforced joint. (3) The initial stiffness and deformability were also greatly improved by the grouted sleeve. (4) The sleeve length coefficient was a key parameter for the improved effect of the grouted sleeve reinforced method.

Comparison between laparoscopic and abdominal radical hysterectomy for stage IB1 and tumor size <2 cm cervical cancer with visible or invisible tumors: a multicentre retrospective study

Pengfei Li,Lan Chen,Yan Ni,Jiaqi Liu,Donglin Li,Jianxin Guo,Zhihua Liu,Shuangling Jin,Yan Xu,Zhiqiang Li,Lu Wang,Xiaonong Bin,Jinghe Lang,Ping Liu,Chunlin Chen 대한부인종양학회 2021 Journal of Gynecologic Oncology Vol.32 No.2

Objective: To compare 5-year disease-free survival (DFS) and overall survival (OS) rates oflaparoscopic radical hysterectomy (LRH) and abdominal radical hysterectomy (ARH) forstage IB1 and tumor size <2 cm with visible or invisible tumors. Methods: We retrospectively compared the oncological outcomes of 1,484 cervical cancerpatients with IB1 and tumor size <2 cm on final pathology, who received ARH (n=899) or LRH(n=585) between January 2004 and December 2016. Patients were divided into visible tumorsubgroup (ARH: n=668, LRH: n=444) and invisible tumor subgroup (ARH: n=231, LRH:n=141) according to tumor type. Results: LRH and ARH showed similar 5-year DFS and OS rates (93.3% vs. 93.1%, p=0.997;96.2% vs. 97.5%, p=0.351) in total study population. LRH was not associated with worse5-year DFS rate (hazard ratio [HR]=0.96; 95% confidence interval [CI]=0.58–1.58; p=0.871)or OS rate (HR=1.37; 95% CI=0.65–2.89; p=0.409) by multivariable analysis. In the visibletumor subgroups, LRH and ARH showed similar 5-year DFS and OS rates (91.9% vs. 91.9%,p=0.933; 95.0% vs. 96.9%, p=0.276), and LRH was not associated with worse 5-year DFS orOS rate (p=0.804, p=0.324). In the invisible tumor subgroups, LRH and ARH also showedsimilar 5-year DFS and OS rates (97.3% vs. 97.1%, p=0.815; 100% vs. 99.5%, p=0.449), andLRH was not associated with worse 5-year DFS rate (p=0.723). Conclusions: Among patients with stage IB1 and tumor size <2 cm, whether the tumor isvisible or not, the oncological outcomes of LRH and ARH among cervical cancer patients arecomparable. This suggests that LRH may be suitable for stage IB1 and tumor size <2 cm withvisible or invisible tumors.Trial Registration: International Clinical Trials Registry Platform Identifier: CHiCTR180017778