Behavior of branch-rotated T joints with cold-formed square hollow sections

2006 ◽  
Vol 33 (7) ◽  
pp. 827-836 ◽  
Author(s):  
Kyu-Woong Bae ◽  
Keum-Sung Park ◽  
Young-Hwan Choi ◽  
Tae-Sup Moon ◽  
S F Stiemer

An experimental investigation of branch-rotated T joints was carried out in which the branch was rotated by 45° with respect to its longitudinal axis. The main experimental parameters were the ratio of the width of the branch to the width of the chord, β′, with 0.38 ≤ β′ ≤ 1.00, and the ratio of the width of the chord to the thickness of the chord, 2γ, with 16.7 ≤ 2γ ≤ 33.3. Experimental results from 27 specimens showed that the ultimate strength increases and the failure mode changes under compression loading due to the rotated branch. The failure modes were out-of-plane bending yielding of the upper flange of the chord for β′ ≤ 0.85 and buckling of the chord web for 0.85 < β′ ≤ 1.00. Theoretical analysis was then carried out to compute the ultimate strength using a yield-line model for β′ ≤ 0.85 and web buckling model for β′ =  1.00. Linear interpolation was used for 0.85 < β′ < 1.00. Design formulas are presented for estimating the strength of T joints with a rotated branch.Key words: hollow structural section, truss T joint connections, yield-line instability, chord web instability, design equations.

1982 ◽  
Vol 9 (2) ◽  
pp. 143-148 ◽  
Author(s):  
R. M. Korol ◽  
H. Mitri ◽  
F. A. Mirza

The carrying capacity of square hollow structural section T-joints stiffened by a rectangular flange plate is investigated for both branch bending moment and punching shear. The ultimate moment or load is determined from the simple yield line method of which one of three failure modes is applicable depending on the plate length. A large number of combinations of branch, chord, and plate sizes are analysed to provide a statistical basis for making recommendations of optimum plate lengths and thicknesses for stiffened joints in Vierendeel truss applications.


2018 ◽  
Vol 37 (12) ◽  
pp. 808-823 ◽  
Author(s):  
Wenbin Hou ◽  
Xianzhe Xu ◽  
Haifeng Wang ◽  
Liyong Tong

This paper presents an analytical, numerical, and experimental study on the failure behavior of single hat-shaped T-joints made of plain woven carbon fiber polymer (T300/epoxy 618) and subjected to out-of-plane bending. The T-joint is manufactured by vacuum bag molding process at room temperature. An analytical model is developed to analyze the experimental results and to establish the associated failure criteria. Two failure modes: (a) laminate buckling and (b) laminate crushing are considered, and the theoretical relationships for predicting the failure load associated with each of the two modes were developed. The experimental data correlate closely with the analytically predicted behavior, including failure mode and bending stiffness. In particular, both laminate buckling and laminate crushing are observed during the experiment with laminate crushing being the final failure mode, which can be considered to be the most important failure mode of the fabricated T-joint. In addition, numerical simulations based on the finite element method and the Hashin damage criteria also accurately predict the flexural modulus, the peak load, and failure locations of the T-joint obtained in the test.


2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori

Pressurized piping systems used for an extended period may develop degradations such as wall thinning or cracks due to aging. It is important to estimate the effects of degradation on the dynamic behavior and to ascertain the failure modes and remaining strength of the piping systems with degradation through experiments and analyses to ensure the seismic safety of degraded piping systems under destructive seismic events. In order to investigate the influence of degradation on the dynamic behavior and failure modes of piping systems with local wall thinning, shake table tests using 3D piping system models were conducted. About 50% full circumferential wall thinning at elbows was considered in the test. Three types of models were used in the shake table tests. The difference of the models was the applied bending direction to the thinned-wall elbow. The bending direction considered in the tests was either of the in-plane bending, out-of-plane bending, or mixed bending of the in-plane and out-of-plane. These models were excited under the same input acceleration until failure occurred. Through these tests, the vibration characteristic and failure modes of the piping models with wall thinning under seismic load were obtained. The test results showed that the out-of-plane bending is not significant for a sound elbow, but should be considered for a thinned-wall elbow, because the life of the piping models with wall thinning subjected to out-of-plane bending may reduce significantly.


Structures ◽  
2021 ◽  
Vol 34 ◽  
pp. 2174-2188
Author(s):  
F. Ahmadpour ◽  
M. Zeinoddini ◽  
M. Mo'tamedi ◽  
R. Rashnooie

Author(s):  
Satoshi Tsunoi ◽  
Akira Mikami ◽  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori

The authors have proposed an analytical model by which they can simulate the dynamic and failure behaviors of piping systems with local wall thinning against seismic loadings. In the previous paper [13], the authors have carried out a series of experimental investigations about dynamic and failure behaviors of the piping system with fully circumferential 50% wall thinning at an elbow or two elbows. In this paper these experiments have been simulated by using the above proposed analytical model and investigated to what extent they can catch the experimental behaviors by simulations.


Author(s):  
Wei Wang ◽  
Weijun Xu ◽  
Xiongliang Yao ◽  
Nana Yang

This paper focuses on the post-ultimate strength behavior of sandwich plates. With widely application of the laminate on the ship and offshore structures, the post-ultimate strength behavior is becoming more important for safety evaluation of structures. Since the post-ultimate strength behavior can reflect the collapse extent of sandwich plate when subjected to extreme loads. A sandwich plate was modeled by FEM, its load-displacement relationship was obtained and its collapse characteristics were analyzed. The load-displacement relationship indicates its post-ultimate strength behavior, which is shown as that the load carrying capacity has a rapidly reduction when the ultimate strength is exceeded, and that the failure modes of the sandwich plate are determined by the parameter of individual layer. The simulation results were validated against experimental results. Conclusions are drawn: the displacement of sandwich plate under axial compression increased slowly before reaching the ultimate strength, once the ultimate strength was exceeded, the loads exerted on the structures sharply decreased with slowly increased displacement until the plate cracked. The simulation results have a good agreement with the experimental results. The mainly failure modes of sandwich plates can be interpreted as delamination between skin & core and core compression fracture, which are typical failure modes in engineering. The stiffness of sandwich structures decreased due to the interlaminar cracking or skin fracture, further the load carrying capacity decreased, which is of significance for guiding the design of sandwich structures.


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