scholarly journals MECHANICAL PERFORMANCE AND SEISMIC RESPONSE OF KNEE BRACE DAMPER STRUCTURE OF H-SA700 HIGH STRENGTH STEEL MEMBERS MADE BY UNDERMATCHED WELDS

2012 ◽  
Vol 77 (682) ◽  
pp. 1959-1968 ◽  
Author(s):  
Naoki SHINSAI ◽  
Keiichiro SUITA ◽  
Yuji KOETAKA

Because of the increase in the levels of residual elements in steel, a programme of work was initiated to determine the limits of copper and tin impurities that were tolerable in steel castings. A 1.5 % Mn—Mo steel was chosen as a base, since any effect of trace elements would be readily apparent in terms of mechanical performance in this medium—high strength steel. The effect of copper was investigated within the range < 0.01-0.5 %, and tin within the range < 0.01-0.26%. The results were analysed by using factorial analysis in the first instance and later, as the amount of experimental work expanded and more results became available, a regression analysis was used.


2020 ◽  
Vol 20 (06) ◽  
pp. 2040007
Author(s):  
Limeng Zhu ◽  
Haipeng Yan ◽  
Po-Chien Hsiao ◽  
Jianhua Zhang

An innovative composite vertical connecting structure (CVC) with capacity carrying and energy-dissipating ability is proposed in this study, which could be used in prefabricated composite shear wall structural systems to enhance the resilience and seismic performance of structural system. The CVC structure is mainly composed of three parts, including the connecting zone, the capacity bearing zone characterized by high strength and elastic deforming ability, and the energy-dissipating zone assembled by replaceable metal dampers. The low-yield strength steel and high-strength steel are used, respectively, for the metal dampers in the energy-dissipating zone and the concrete-filled high-strength steel tubes in the bearing capacity zone to enhance the energy dissipation and self-centering abilities of CVC structures. The working mechanism is analyzed and validated through finite element models built in ABAQUS. The hysteretic behavior is simulated to evaluate their performance. First, the metal dampers are designed. The theoretical and finite elemental parametric analysis are carried out. According to the simulation results, the “Z-shaped” metal dampers exhibit better energy-dissipating ability than the rectangular shape, in which the “Z-shaped” metal dampers with 45∘ show the best performance. Simultaneously, the results of the models calculated by the finite element method and theoretical analysis work very well with each other. Furthermore, seven FE models of shear walls with CVC structures are designed. Monotonic and cyclic loading simulations are conducted. The failure modes and comprehensive mechanical performance are investigated and evaluated according to their calculated force–displacement curves, skeleton curves, and ductility coefficients. The results indicate that the CVC structure delivered preferable lateral-bearing capacity and displacement ductility. Finally, according to available design standards, the lateral stiffness of CVC structures could be conventionally controlled and some practical design recommendations are discussed.


2015 ◽  
Vol 744-746 ◽  
pp. 265-273
Author(s):  
Xi Yu Wang ◽  
Yong Feng Luo ◽  
Xu Hong Qiang ◽  
Xiao Liu

Past three decades have seen the rapid development of high strength steel (HSS) in its application in structural engineering. However, so far the mechanical performance of a HSS beam-to-column connection has not been systematically studied, especially for bolted end-plate connections, the commonly employed beam-to-column connections in steel structures, which could restrict the application of HSS. Therefore, this paper aims to represent the basic methods, current achievements, recent applications, and the existing problems that lie in the way. In doing so, this paper is composed of three parts, experimental results, numerical analysis as well as component method. At the end, this paper indicates that future investigation should be based upon experimental analysis and proper finite element modeling, to verify a numerical model and to refine design standards.


2014 ◽  
Vol 638-640 ◽  
pp. 101-104
Author(s):  
Yi Liang Peng ◽  
Guo Tian Li ◽  
Xuan Min Han ◽  
Lei Chen

With the rapid development of power transmission and transformation projects in China, steel supporting structure has already became the most popular structural form for these structures. However, the limit of steel grade used for current substation supporting structures is normally Q420, compared with that of Q690 used in other countries. When the high-strength steel is used, the geometric parameters of section for members become smaller, and the stability of members is the most important factors to influence the bearing capacity of structures. The stability factor for axial loaded steel members in current 《Code for design of steel structures》(GB50017-2003) was derived based on the experimental results for steel members with lower steel grade, the results are inevitably different from those for high-strength steel members. To make the calculations of Q690 high-strength steel tubes more accurate and reasonable, this paper conducts experimental study on the bearing capacity of Q690 high-strength steel tubes under axial load to provide scientific basis for practical design of these structures.


2007 ◽  
Vol 537-538 ◽  
pp. 679-686 ◽  
Author(s):  
Hardy Mohrbacher ◽  
Christian Klinkenberg

Modern vehicle bodies make intensive use of high strength steel grades to improve the weight and the mechanical performance simultaneously. A broad range of medium and extra high strength steel grades is available. These steel grades have different characteristics concerning strength, formability and weldability. For many steel grades microalloying by niobium is the key to achieve their characteristic property profile. In HSLA steels niobium enhances the strength primarily by grain refinement. In interstitial free high strength steels niobium serves as a stabilizing element and also assists in obtaining the bake hardening effect. Some modern multiphase steels rely on niobium to achieve additional strength via grain refinement and precipitation hardening. Microstructural control provides a way to further optimize properties relevant to automotive processing such as cutting, forming and welding. The relevance of niobium microalloying in that respect will be outlined.


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