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Nishi-Tokyo-shi, Japan

Hao X.-Y.,Dalian University of Technology | Li H.-N.,Dalian University of Technology | Toshio M.,Sumikin Kansai Industries CO.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2014

The shaking table tests of a steel structure with innovative H type steel-unbuckling-braces (SUB) and with conventional central braces were conducted to compare the dynamic characteristics and seismic responses of the structure with one of the two kinds of braces. The effect of the two braces on seismic behaviors of the structure were analysed respectively. A finite element analysis was carried out and its result was compared with the experimental result. The results of tests and calculations show that the Innovative H type Steel-Unbuckling- Brace presented provides initial stiffness as the conventional central brace and the layer displacement of the two frameworks is almost the same in normal using. But the layer displacement of the framework with H type SUB is far less than that with conventional brace under middle and strong earthquakes, because the SUB dissipates earthquake input energy before the framework enters into the stage of elastic-plastic degeneration, which will reduce the structural damage. Source

Hao X.-Y.,Dalian University of Technology | Li H.-N.,Dalian University of Technology | Yang C.-M.,Dalian University of Technology | Makino T.,Sumikin Kansai Industries CO.
Zhendong Gongcheng Xuebao/Journal of Vibration Engineering | Year: 2012

As a new type of prospective component for energy dissipation and vibration reduction, unbuckling-brace is a composite bracing member which can act as conventional central brace without buckling and displacement type damper, and overcomes the shortcoming of buckling characteristics of conventional braces. In this paper, H type steel-unbuckling-brace (SUB) which was welded by using steel flats and core made of low yield steel was presented at first. Quasi-static tests with reciprocating loads were conducted on four steel H type unbuckling-brace specimens for testing the seismic performances. The loading process and energy dissipation mechanism of these SUB specimens were studied, moreover, seismic performances, such as force-displacement hysteretic curve, resilience model, accumulative plastic deformation and energy dissipation capability are analyzed too. At last the hysteretic curves for the specimens were simulated based on ANSYS and compared with the experimental results. The better hysteretic behavior and high energy dissipation of SUB were verified. Numerical simulation results show that the frame structure with H type steel-unbuckling-brace has good seismic absorption effect. Source

Hao X.-Y.,Dalian University of Technology | Li H.-N.,Dalian University of Technology | Li G.,Dalian University of Technology | Makino T.,Sumikin Kansai Industries CO.
Structural Design of Tall and Special Buildings | Year: 2014

The unbuckling brace, acting as a combination of a conventional brace and displacement-dependent damper, can successfully avoid the bucking and consequent fracture compared with the conventional brace, which has been widely applied in concentrically braced frame structures. In this paper, the H-type steel unbuckling brace (SUB), which is welded by steel flats and core made of low-yield steel, is presented. The quasi-static tests, the shaking table tests of a steel structure with SUBs and conventional central braces and the numerical analysis of a real steel building with and without SUBs are conducted in this study to evaluate the performance of SUBs. The results demonstrate that the SUBs have excellent plastic deformation capacity, stable energy dissipation capacity and no stiffness degradation, and can provide certain initial stiffness to the structure and dissipate earthquake input energy by yielding behaviour. Moreover, it is effective in reducing the structural response, and in particular, in controlling the structural displacement. In conclusion, the SUB proposed is a lateral resistant member with high stiffness and strength and an excellent energy dissipation device, which is much more competitive than the conventional brace in improving lateral resistance and seismic performance of the frame structure. © 2013 John Wiley & Sons, Ltd. Source

Pilchak A.L.,Air Force Research Lab | Nakase K.,Sumikin Kansai Industries CO. | Inagaki I.,Nippon Steel & Sumitomo Metal Corporation | Shirai Y.,Nippon Steel & Sumitomo Metal Corporation | And 2 more authors.
Ti 2011 - Proceedings of the 12th World Conference on Titanium | Year: 2012

The strain paths and thermal cycles utilized during thermomechanical processing of two-phase alloys have a pronounced influence on the resulting distribution of grain orientations present and their spatial distribution. For example, large regions of similarly oriented α grains, commonly referred to as microtextured regions or macrozones,may persist despite the imposition of large macroscopic strains. The detrimental effect of microtexture on dwell fatigue life of high temperature alloys is well established; however,considerably less attention has been given to the effects of microtexture on fatigue life during continuous cycling . In the present work, the effects of microstructure and microtexture on the low cycle fatigue (N f≤ 104 cycles) behavior of Ti-6A1-4V have been characterized using electron microscopy. Microstructural parameters such as the volume fraction and size of the α phase were assessedby quantitative metallography while the contiguity of the α phase and the size and shape of the microtextured regions were investigated with electron backscatter diffraction. Variations in microstructure and microtexture due to subtle differences in thermomechanical processing routes have been correlated with variations in fatigue life through the use of quantitative fractography techniques. Using these methods the spatial and crystallographic orientations of fracture facets at small crack lengths have been determined. The results indicate that grains with c-axes are oriented between approximately 25° and 55° from the stress axis are most likely to form cracks that propagate by facet formation on the basal plane. Crack advance by faceted growth occurs readily through grains with similar basal plane orientation and,as a result,the contiguity of equiaxed α grains with basal poles in the 25°-55° range is an important parameter governing low cycle fatigue life. Source

Wang J.-J.,Key Laboratory of Civil Engineering Safety and Durability of China Education Ministry | Shi Y.-J.,Key Laboratory of Civil Engineering Safety and Durability of China Education Ministry | Wang Y.-Q.,Key Laboratory of Civil Engineering Safety and Durability of China Education Ministry | Pan P.,Key Laboratory of Civil Engineering Safety and Durability of China Education Ministry | And 2 more authors.
Zhejiang Daxue Xuebao (Gongxue Ban)/Journal of Zhejiang University (Engineering Science) | Year: 2015

In order to simulate the earthquake response of low yield point steel, its constitutive relationship under cyclic loading needs to be studied. Twenty specimens of low yield point steel LYP100 were tested under sixteen different loading systems. Monotonic curves, hysteretic curves, failure modes and ductility properties were analyzed. Skeleton curves under cyclic loading with strain increasing step by step were fitted based on Ramberg-Osgood model. And parameters of isotropic hardening and kinematic hardening were calibrated from test data. The calibration was then verified by finite element results simulated in ABAQUS. Results show that, LYP100 steel exhibits a large degree of cyclic hardening; LYP100 has excellent ductility even after being subjected to cyclic loading; Ramberg-Osgood model fits skeleton curves well under cyclic loading with strain increasing step by step; finite element results fit test results well when calibrated hardening parameters are input into ABAQUS. ©, 2015, Zhejiang University. All right reserved. Source

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