scholarly journals Experimental study on fatigue performance of Q420qD high-performance steel cross joint in complex environment

2021 ◽  
Author(s):  
Haigen Cheng ◽  
Cong Hu ◽  
Yong Jiang
Keyword(s):  
Fatigue Life ◽  
High Performance ◽  
Steel Structure ◽  
Steel Structures ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Corrosive Media ◽  
Joint Connection ◽  
High Performance Steel ◽  
The Cross

AbstractThe steel structure under the action of alternating load for a long time is prone to fatigue failure and affects the safety of the engineering structure. For steel structures in complex environments such as corrosive media and fires, the remaining fatigue life is more difficult to predict theoretically. To this end, the article carried out fatigue tests on Q420qD high-performance steel cross joints under three different working conditions, established a 95% survival rate $$S{ - }N$$ S - N curves, and analyzed the effects of corrosive media and high fire temperatures on its fatigue performance. And refer to the current specifications to evaluate its fatigue performance. The results show that the fatigue performance of the cross joint connection is reduced under the influence of corrosive medium, and the fatigue performance of the cross joint connection is improved under the high temperature of fire. When the number of cycles is more than 200,000 times, the design curves of EN code, GBJ code, and GB code can better predict the fatigue life of cross joints without treatment, only corrosion treatment, and corrosion and fire treatment, and all have sufficient safety reserve.

scholarly journals Mechanical Behavior of Damaged H-Section Steel Structure

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xibing Hu ◽  
Rui Chen ◽  
Yuxuan Xiang ◽  
Yafang Chen ◽  
Qingshan Li
Keyword(s):  
Cross Sections ◽  
Elastic Moduli ◽  
Mechanical Test ◽  
Steel Structure ◽  
Steel Structures ◽  
Computational Accuracy ◽  
Cross Sectional ◽  
Steel Columns ◽  
Steel Members ◽  
The Cross

Steel structures are usually damaged by disasters. According to the influence law of the damage on the elastic modulus of steel obtained by the mechanical test of damaged steel, the average elastic moduli of H-section steel members were analyzed. The equations for calculating the average elastic moduli of damaged H-section steel members at different damage degrees were obtained. By using the analytical cross-sectional method, the cross-sectional M-Φ-P relationships and the dimensionless parameter equations of the H-sections in the full-sectional elastic distribution, single-sided plastic distribution, and double-sided plastic distribution were derived. On the basis of the cross-sectional M-Φ-P relationships and dimensionless parameters of actual steel members, the approximate calculation equations for the damaged cross sections were obtained. The Newmark method was used to analyze the deformation of damaged steel columns. Analytical results show good agreement with the test results. The equations and methods proposed in this study have high computational accuracy, and these can be applied to the cross-sectional M-Φ-P relationships and deformation calculation of damaged steel members.

The Effect of Asphalt Binder Aging on Fatigue Performance of Evotherm WMA

2012 ◽  
Vol 535-537 ◽  
pp. 1686-1692
Author(s):  
Yong Chun Qin ◽  
Sui Yuan Wang ◽  
Wei Zeng ◽  
Xiao Pei Shi ◽  
Jian Xu ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Warm Mix Asphalt ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Asphalt Binders ◽  
Different Temperatures ◽  
Binder Aging ◽  
Lower Production

One of the main benefits advertised with the use of warm mix asphalt (WMA) is the decreasing aging of the asphalt binder resulting from the lower production temperature compared to conventional hot mix asphalt (HMA). Some tests were performed to determine the asphalt binder aging properties from WMA and HMA. Asphalt binders were recovered by extraction and distillation from asphalt mixtures premixed at different temperatures (140°C, 160°C, 180°C for HMA, 100°C and 120°C for WMA) in the mixing plant. Penetration@25°C, softening point (R&B) and rotational Brookfield viscosity tests were carried out. Results show that the aging of asphalt binder increases as the mixing temperature is elevated, and remarkably accelerates at the temperatures higher than 150°C. Warm mix asphalt (for example, mixing temperature at 100°Cor 120°C) can greatly reduce the aging of asphalt. Aging of the asphalt binder is one of the factors that would affect the mixture’s fatigue life. Four-point beam fatigue test samples were mixed and compacted at 140°C for HMA and 120°C for WMA, and fatigue tests with a frequency of 10 Hz and three constant strain levels (150 micro-strain, 300 micro-strain, 450 micro-strain, respectively) were performed. Results show that WMA’s fatigue life was higher than the control HMA, which indicates that it may reduce aging of asphalt binder and improve fatigue performance of asphalt mixture at lower production temperatures.

ANALYSIS AND DESIGN OF MULTI-STOREY STEEL STRUCTURES WITH IRRIGATION TO TORQUE ACCORDING TO 2018 EARTHQUAKE REGULATIONS

2021 ◽  
Vol 0 (15) ◽  
pp. 0-0
Author(s):  
Fahım Ahmad NOWBAHARI ◽  
Elif AĞCAKOCA
Keyword(s):  
Steel Structure ◽  
Steel Structures ◽  
Seismic Load ◽  
Finite Element Program ◽  
Analysis And Design ◽  
Earthquake Resistant Structures ◽  
Cross Member ◽  
Element Program ◽  
The Cross ◽  
Design Earthquake

When observing the consequences of earthquakes, it is accepted that earthquakes are one of the most dangerous natural disasters in the world. Therefore, special engineering methods are used to explore and analyze the effects of earthquakes on structures and to design earthquake resistant structures accordingly. In applying these methods, it is important to investigate the irregularities in the carrier system correctly. There are six irregularities in the Turkish Building Earthquake Code (TBDY-2018), one of the most important of which is A1 Torsional Irregularity [TBDY 2018]. In this article, considering TBDY 2018, the dynamic behaviour of structures with different ratios of torsional irregularity in multi-storey steel structures is examined. In a 10-storey steel structure with the same purpose and size, four type models were produced using the central inverted V cross member and changing the cross positions. The Equivalent Seismic Load Method is used in the analysis. Structural analyzes were performed with the "ETABS" finite element program. As a result of these studies; The displacements obtained from the structural analysis of 4 models with different torsional irregularity coefficients due to the cross member placement in various places in 4 buildings with the same dimensions were calculated by the Equivalent Seismic Load method.

Study of Fatigue Tests on the Structural Details of Welding Joints of Integral Bridge Deck and Main Girder Gusset Plates

2011 ◽  
Vol 243-249 ◽  
pp. 1638-1645
Author(s):  
Cai Ping Huang ◽  
Zhong Xian Zhang ◽  
Ji Zhang ◽  
Jin Zhou Chen
Keyword(s):  
Fatigue Life ◽  
Bridge Deck ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Scale Model ◽  
Gusset Plates ◽  
Integral Bridge ◽  
Structural Details ◽  
Tensile Forces ◽  
Welding Joints

Under the action of both dead and live loads, the welding joints of the integral bridge deck and the main truss gusset plates of a steel truss bridge in the transverse and longitudinal directions are all subjected to tensile force, the fatigue performance of which greatly influence the safety and durability of the bridge during operation. Fatigue tests were carried out on a full-scale model designed and made in accordance with the structural details of the welding joints of the integral bridge deck and the main truss gusset plates of Dashengguan Changjiang River Bridge. On the basis of the results of the fatigue tests, the stress distribution of the welding joints was analyzed, the fatigue life of the welding joints under load cycles with constant amplitude was discussed and the fatigue performance of the welding joints under the condition of two-way tensile forces was studied. It is concluded that under the effect of fatigue loading with given amplitude, the fatigue life of the welding joints is more than 200 million numbers of load cycles, the structural details of welding joints have ample fatigue resistant ability under the condition of two-way tensile forces, and the maximum main stress value of the fatigue tests is lower than the allowable fatigue stress value given in various codes and relevant references and the fatigue strength meets requirement.

scholarly journals Balance Fatigue Design of Cast Steel Nodes in Tubular Steel Structures

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Libin Wang ◽  
Hui Jin ◽  
Haiwei Dong ◽  
Jing Li
Keyword(s):  
Fatigue Life ◽  
Fatigue Behavior ◽  
Cast Steel ◽  
Steel Structure ◽  
Steel Structures ◽  
Crack Size ◽  
Initial Crack ◽  
Fatigue Design ◽  
Joint Application ◽  
Mechanical Performances

Cast steel nodes are being increasingly popular in steel structure joint application as their advanced mechanical performances and flexible forms. This kind of joints improves the structural antifatigue capability observably and is expected to be widely used in the structures with fatigue loadings. Cast steel node joint consists of two parts: casting itself and the welds between the node and the steel member. The fatigue resistances of these two parts are very different; the experiment results showed very clearly that the fatigue behavior was governed by the welds in all tested configurations. This paper focuses on the balance fatigue design of these two parts in a cast steel node joint using fracture mechanics and FEM. The defects in castings are simulated by cracks conservatively. The final crack size is decided by the minimum of 90% of the wall thickness and the value deduced by fracture toughness. The allowable initial crack size could be obtained through the integral of Paris equation when the crack propagation life is considered equal to the weld fatigue life; therefore, the two parts in a cast steel node joint will have a balance fatigue life.

scholarly journals Effects of Machining Induced Residual Shear and Normal Stresses on Fatigue Life and Stress Intensity Factor of Inconel 718

2019 ◽  
Vol 9 (22) ◽  
pp. 4750
Author(s):  
Yang Hua ◽  
Zhanqiang Liu
Keyword(s):  
Experimental Data ◽  
Stress Intensity Factor ◽  
Fatigue Life ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Inconel 718 ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Shear Stresses ◽  
Normal Stresses

Residual shear stresses and normal stresses induced by machining affect the fatigue performance of components. Thus, residual shear and normal stresses should be considered simultaneously when evaluating the influence of residual stress on fatigue performance. In the present paper, the influences of residual shear and normal stresses on the fatigue life and stress intensity factor (SIF) of turned Inconel 718 were investigated. Firstly, the cos α measurement method was utilized to calculate the residual shear stress and residual normal stress of turned Inconel 718. Then, the combined effects of residual shear and normal stresses on fatigue life were evaluated through uniaxial tension–tension fatigue tests. Thirdly, a prediction model for the SIF was proposed by taking the residual shear and normal stresses into account. Finally, the predicted SIF was validated by the published experimental data from the literature. The predicted results of the proposed model generally agreed well with the available experimental data.

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