Study of Failure Modes of Suction Anchors

Author(s):  
Qiyi Zhang ◽  
Sheng Dong

Suction foundations are widely used in deep sea and their ultimate bearing capacity which is closely related with failure modes of suction anchor at limit equilibrium state is a key technology in offshore engineering practice. Based on Coulomb friction theory, an exact finite element model is presented in this paper. On the basis of this FEM model, by use of the finite element analysis software ABAQUS, the effect of mooring point and aspect ratio of a suction anchor on the ultimate bearing capacity and its stability are researched in detail. The results show that the ultimate bearing capacity and stability of the suction anchor are affected vastly by the position of mooring point, and the variation of mooring point on the suction anchor can lead to different failure modes. Simultaneously, the results also shows that tilted rotation of the soil along the direction of the mooring force will occur when the mooring point is near the top of the suction anchor, and the soil near the bottom of the fixed anchor rotates around the center of a circle, so the failure mode is called forward-tilted rotation in this paper; A general translation slip of the soil in front of the anchor along the direction of the mooring force will occur when mooring point is below midpoint of suction anchor, so the failure mode is called the translation slip failure mode in this paper. Anticlockwise tilted rotation of the soil along the direction of mooting force will occur when the mooring point is near the bottom of the anchor, and the soil at the top of the anchor rotates around the center of a circle, so the failure mode is called backward-tilted rotation in this paper.

2018 ◽  
Vol 27 (1) ◽  
pp. 096369351802700
Author(s):  
Xiong Xueyu ◽  
Wang Yiqingzi ◽  
Xue Rongjun ◽  
Lu Xuanxing

As Chinese architecture masterpiece, ancient Hui-style architecture is the admiration for Chinese and foreign master builders. According to the bending test, the theoretical calculations and Abaqus finite element analysis on 5 Hui-style architecture beams, this paper points out the differences between un-reinforced beams and reinforced beams on ultimate bearing capacity, deflection and other performance indicators. The reinforcement methods of embedding steel bars, embedding CFRP bars and pasting CFRP plate can respectively improve the ultimate bearing capacity by 20.2%, 32.6% and 37.0%. Based on the plane section assumption and considering thereduction of tensile strength causedby wood knots and defects in tension zone, this paper predicts failure modes of the test beams may occur, and gives the ultimate bearing capacity of different failure modes. In addition, this paper uses the Abaqus finite element software for simulating test beams, and the development trend of load-deflectioncurve between the test and numerical simulation are in good agreement, providing reference for further research of Hui-style architecture.


2011 ◽  
Vol 368-373 ◽  
pp. 473-477
Author(s):  
Xing Ping Shu ◽  
Zhi Shen Yuan ◽  
Zheng Rong Zhu ◽  
Yao Yao

This paper presents the experimental and numerical results of the ultimate bearing capacity of partially overlapped tubular N-joints, which have circular hollow section (CHS) brace members welded to a square hollow section (SHS) chord member. Two partially overlapped N-joints were tested to failure under overlapping brace axial loading and chord axial loading. The failure mode of specimen N1 was the overlapping brace local bucking, and the failure mode of specimen N2 was the chord face plastification with chord side wall buckling. Meanwhile, weld fracture occurred on both specimens. Then, making use of finite element package program ANSYS, in which twenty nodes solid element was employed and the weld was simulated, elastic-plastic large deflection finite element analysis of the experimental joints was conducted. The experimental data were compared with the results acquired by finite element analysis and it was proved that ANSYS is feasible to simulate the connecting weld and analyze the static behavior of partially overlapped CHS-to-SHS welded N-joints.


2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Chengquan Wang ◽  
Yonggang Shen ◽  
Runfang Yang ◽  
Zuolin Wen

Nonlinear numerical analysis of the structural behaviour of prestressed steel reinforced concrete (PSRC) beams was carried out by using finite element analysis software ABAQUS. By comparing the load-deformation curves, the rationality and reliability of the finite element model have been confirmed; moreover, the changes of the beam stiffness and stress in the forcing process and the ultimate bearing capacity of the beam were analyzed. Based on the model, the effect of prestressed force, and H-steel to the stiffness, the ultimate bearing capacity and ductility of beam were also analyzed.


2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Xianglong Liu ◽  
Jicheng Zhang ◽  
Hailin Lu ◽  
Ning Guan ◽  
Jiahao Xiao ◽  
...  

The mechanical properties of T-shaped concrete-filled steel tubular (TCFST) short columns under axial compression after elevated temperature are investigated in this paper. A total of 30 TCFST short columns with different temperature (T), steel ratio (α), and duration of heating (t) were tested. The TCFST column was directly fabricated by welding two rectangular steel tubes together. The study mainly investigated the failure modes, the ultimate bearing capacity, the load-displacement, and the load-strain performance of the TCFST short columns. Experimental results indicate that the rectangular steel tubes of the TCFST column have deformation consistency, and the failure mode consists of local crack, drum damage, and shear failure. Additionally, the influence of high temperature on the residual bearing capacity of the TCFST is significant, e.g., a higher temperature can downgrade the ultimate bearing capacity. Finally, a finite element model (FEM) is developed to simulate the performance of the TCFST short columns under elevated temperature, and the results agree with experimental values well. Overall, this investigation can provide some guidance for future studies on damage assessment and reinforcement of the TCFST columns.


2020 ◽  
pp. 136943322096527
Author(s):  
Longji Dang ◽  
Rui Pang ◽  
Rui Liu ◽  
Hongmei Ni ◽  
Shuting Liang

This paper aims to investigate the seismic performance of hollow floor interior slab-column connection (HFISC). In this new connection system, several tube fillers are placed in slab to form hollow concrete. Moreover, locally solid zone, shear components, and hidden beam around the connections are installed to improve the bearing capacity and ductility of specimens. Three slab-column connections with different shear components were tested under cyclic loading and every specimen was constructed with parallel tube fillers in the north direction and orthogonal tube fillers in the south direction. The seismic behavior of specimens was evaluated according to the hysteretic response, skeleton curve, ductility, stiffness degradation, and energy dissipation. A finite element model was then developed and validated by a comparison with the experimental results. Based on experimental results and finite element analysis results, the relative effects of the hollow ratio of slab, the ratio of longitudinal reinforcement, the shear area of bent-up steel bars, and the arm length of welding section steel cross bridging were elucidated through parametric studies. This new slab-column connection showed better plastic deformation capacity while the bearing capacity was kept. Specimens with parallel tube fillers showed better seismic behavior than those of specimens with orthogonal tube fillers.


2011 ◽  
Vol 306-307 ◽  
pp. 733-737
Author(s):  
Xu Dan Dang ◽  
Xin Li Wang ◽  
Hong Song Zhang ◽  
Jun Xiao

In this article the finite element software was used to analyse the values for compressive strength of X-cor sandwich. During the analysis, the failure criteria and materials stiffness degradation rules of failure mechanisms were proposed. The failure processes and failure modes were also clarified. In the finite element model we used the distributions of failure elements to simulate the failure processes. Meanwhile the failure mechanisms of X-cor sandwich were explained. The finite element analysis indicates that the resin regions of Z-pin tips fail firstly and the Z-pins fail secondly. The dominant failure mode is the Z-pin elastic buckling and the propagation paths of failure elements are dispersive. Through contrast the finite element values and test results are consistent well and the error range is -7.6%~9.5%. Therefore the failure criteria and stiffness degradation rules are reasonable and the model can be used to predict the compressive strength of X-cor sandwich.


2014 ◽  
Vol 578-579 ◽  
pp. 751-756
Author(s):  
Bin Li ◽  
Qun Hui Zhang ◽  
Chun Yan Gao

Nonlinear finite element parameters analysis on the lattice type steel pipe concrete wind turbine tower, it shows the entire process of load bearing, failure mode and ultimate bearing capacity, researches on the influence law of aspect ratio, form of tower webs, tower diameter to thickness ratio and web member stiffness to tower column stiffness ratio on the ultimate bearing capacity and tower failure mode. The finite element analysis results shows that the tower aspect ratio λ, the diameter-thickness ratio γ of tower columns and the increase of stiffness ratio β between web members and tower columns has great influence on ultimate bearing capacity and failure mode, while the form of webs has small influence on that. with the increase of tower aspect ratio λ, the decrease of diameter-thickness ratio γ of tower columns and the increase of stiffness ratio β between web members and tower columns, the ultimate bearing capacity of this kind of latticed towers increase, the failure mode changed from Web local buckling to The combined damage of Web local buckling and the tension tower yield. This paper suggests that in the design of wind turbulent generator tower, the tower aspect ratio λ should be best controlled at 1/9, the bottom layers of this kind of tower should best use the re-divided web members, and other web member forms used on above layers, the diameter-thickness ratio γ of tower column should be taken less than 30, and the stiffness ratio β between webs and columns should be controlled less than 0.05 in order to avoid damage occurring on the tower columns earlier than the webs. The results can provide evidence for the engineering design.


2014 ◽  
Vol 578-579 ◽  
pp. 278-281
Author(s):  
Pi Yuan Xu ◽  
Qian Chen ◽  
Ya Feng Xu

In this paper, in order to understand fully the development of failure mechanism, bearing capacity and seismic performance of the steel H-beams and composite concrete filled steel tubular (CFST) column joints strengthened by outside strengthening ring, in the space zone the effects of changing the axial compression ratio is investigated. A 3D joint finite element model is built up by finite element software ABAQUS, the elastic-plastic finite element analysis is carried through numerical modeling process. The analysis results showed that low axial compression ratio has a little influence on the bearing capacity; with the increase of axial pressure the bearing capacity will decrease in a high axial compression ratio, moreover the failure pattern of joint changes from beam end to column end. The ductility of the specimens is decreased by raising axial compression ratio.


2014 ◽  
Vol 633-634 ◽  
pp. 922-926
Author(s):  
Li Hua Zhang ◽  
Li Yu ◽  
Zhe Jun Quan

This essay analyzes stress between pile and soil, occupying moisture content data of unsaturated soil in Nanchang with ANSYS. In accordance with engineering practice, it adopts three-dimensional solid model, the same geometric size with engineering practice. It simulates interrelation between pile and soil with contact unit, and shows ontology relation of soil with D-P elastic-plastic model. Convergence has been made with selection and calculation of parameter. The greater the moisture content gets, the smaller the pile body vertical displacement makes. In other words, the smaller the relative displacement between pile and soil gets, the lower the lateral extrusion stress from pile to soil becomes. Keywords: unsaturated soil; shear strength; pile bearing capacity; finite element analysis; moisture content


2012 ◽  
Vol 193-194 ◽  
pp. 1461-1464
Author(s):  
Bai Shou Li ◽  
Ai Hua Jin

Based on the characteristics of the special-shaped concrete-filled steel tubes and consideration of material nonlinearity of constitutive relation, stimulation of 6 T-shaped thin-walled ribbed and un-ribbed concrete-filled steel tube short columns is implemented, as well as comparable analysis of stress, strain, displacement and bearing capacity, through the finite element analysis software ANSYS. The result indicates that the rib can effectively improve the ductility, delaying the buckling occurs, which enhances the core concrete confinement effect, so as the stimulated ultimate bearing capacity which is greater than nominal ultimate bearing capacity.


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