Energy Absorption Capacity of Thermally Sprayed Aluminium Friction Damper

Author(s):  
S. Ono ◽  
Japan K. Nakahira ◽  
S. Tsujioka ◽  
K. Inoue

Abstract When buildings are subjected to earthquakes, dampers are effective in decreasing their failure by absorbing the input energy. An object of this study is to develop a new type of friction damper, on whose faying surface aluminium is sprayed, and the double friction joint is tightened with a high-strength bolt. When slip occurs on this friction damper, the slip coefficient is high and comparatively stable. Specimens of the friction damper were tested under the dynamic repeated loading condition to investigate the effect of the condition of the faying surface on the dynamic hysteresis characteristics. The parameters of the test are the type of sprayed metal, the sprayed side of the plate(s), thickness of sprayed metal, the finish of the sprayed surface, and initial clamping force (contact pressure). Results indicate that there exists the condition of suitable characteristics of a metal sprayed friction damper.

2021 ◽  
Vol 2 (2) ◽  
pp. 1-5
Author(s):  
Nwzad Abduljabar Abdulla

This research documents the results of tests on stub columns tested under repeated monotonic compression load. Two unplasticized polyvinyl chloride (uPVC) tubes were filled with normal and high strength concrete. From each type of concrete three control specimens were also cast for comparison purposes. The experimental test results show that the unconfined specimens were crushed in the first cycle of loading in contrast to the confined specimens which continued to resist the applied load after several cycles of repeated loading. Furthermore, by using the polymeric tube, the failure of concrete core switches from sudden explosive failure to non-brittle failure with the composite specimen undergoing large progressive deformation in each cycle of loading. For each cycle of loading, the material damage in the composite system was evaluated in terms of the deformations in both the lateral and axial directions.


Alloy Digest ◽  
1995 ◽  
Vol 44 (7) ◽  

Abstract ALUMINUM ALLOY 201.0 is a structural casting alloy available as sand, permanent mold and investment castings. It is used in structural casting members, applications requiring high tensile and yield strengths with moderate elongation, and where high strength and energy-absorption capacity are needed. This datasheet provides information on composition, physical properties, and elasticity as well as creep and fatigue. It also includes information on high temperature performance as well as casting, heat treating, machining, joining, and surface treatment. Filing Code: AL-336. Producer or source: Various aluminum companies.


Robotica ◽  
2005 ◽  
Vol 24 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Hyeung-Sik Choi ◽  
Yong-Heon Park

We developed a new type of a human-sized BWR (biped walking robot) driven by the closed-chain type of a joint actuator. Each leg of the BWR is composed of three pitch joints and one roll joint. In all, a 12 degree-of-freedom robot, including four arm joints, was developed. The BWR was designed to walk autonomously; it is actuated by small 90W DC motors/drivers and is has DC batteries and controllers. A new type of the joint actuator for the BWR is composed of the four-bar-link mechanism driven by a ball screw which has high strength and high gear ratio despite its light weight.In this paper, analyses on the four-bar-link mechanism applied to the joint actuator and on the structure of the BWR are presented. Through walking experiments of the BWR, the superior trajectory-tracking ability of the proposed joint actuator is validated.


2021 ◽  
Author(s):  
Hitoshi Moriyama ◽  
Ryo Sakura ◽  
Takashi Yamaguchi ◽  
Takai Toshikazu ◽  
Yuta Yamamoto

<p>Welded joints is adopted rather than bolted joints for megastructure’s connections because the former can carry large force. However, the former has several problems, such as quality control of welding in situ, which the latter can solve. By contrast, as the load transfer ratio of each bolt becomes uneven proportionally to the number of bolts, local slip around extreme bolts occurs before the whole slip. Extreme bolts to which a large shear force is applied will break before other bolts. For utilizing the strength of all bolts, the problem is solved by improving shear deformation capacity in faying surface with novel surface treatment. Here, the treatment concepts were explored, and the coating’s effectiveness was evaluated through friction tests. The deformation capacity can be twice or more than that of conventional treatment, and the slip coefficient doesn’t depend on contact pressure. These features have the advantage to give stable slip behaviour.</p>


2016 ◽  
Vol 693 ◽  
pp. 800-806
Author(s):  
You Dan Guo

In high-strength steel hot forming, under the heating and quenching interaction, the material is oxidized and de-carbonized in the surface layer, forming a gradual change microstructure composed of ferrite, ferrite and martensite mixture and full martensite layers from surface to interior. The experiment enunciation: Form the table to ferrite, ferrite and martensite hybrid organization, completely martensite gradual change microstructure,and make the strength and rigidity of material one by one in order lower from inside to surface, ductility one by one in order increment in 22MnB5 for hot forming;Changes depends on the hot forming process temperature and the control of reheating furnace gas content protection, when oxygen levels of 5% protective gas, can better prevent oxidation and decarburization;Boron segregation in the grain boundary, solid solution strengthening, is a major cause of strength increase in ;The gradual change microstructure in outer big elongation properties, make the structure of the peak force is relatively flat, to reduce the peak impact force of structure, keep the structure of high energy absorption capacity;With lower temperature, the material yield strength rise rapidly,when the temperature is 650 °C, the yield strength at 950 °C was more than 3 times as much.


2011 ◽  
Vol 255-260 ◽  
pp. 1198-1203 ◽  
Author(s):  
Ye Sheng

The weakness of traditional dumbbell-shaped section is that when concrete is filled into the web space, great stress is likely to produce cracks in the weld sealing between steel tube and web plates. In order to avoid this condition, a new-type dumbbell-shaped section is proposed. Experiments on concrete filled steel tubular (CFST) model arches with new-type dumbbell-shaped section have been carried out, concentrated loading at crown and L/4 section respectively. The result indicated that the new-type CFST arch has good elastic-plastic behavior and high strength, no local buckling appeared during the whole loading process, its in-plane mechanic behavior is similar with that of the CFST arch with single-tube. The dual nonlinear finite element calculation model is set up for the model arch, by means of this model the load-deflection curves during the loading process and the ultimate load-carrying capacity is analyzed.


2021 ◽  
Vol 248 ◽  
pp. 01054
Author(s):  
Zhigang Wang ◽  
Yun Xiang ◽  
Ziqi Yi ◽  
Longfei He ◽  
Mingjie Chen ◽  
...  

Insulation pull rods are commonly used tools and instruments in the replacement of insulators for live work. Traditional hard insulated pull rods are difficult to transport and assemble due to their large deflection, especially due to the long and heavy weight of insulated pull rods used in UHV live operations, the difficulties in the above links are more obvious. In view of the existing problems in the use of the existing insulated pull rods, by studying the overall processing type, the soft pull rod weaving process, the technology of tightly combining the core rod and the protective cover, the technology of connecting the core rod and the metal, etc., a new type suitable for live transmission lines has been developed. Large-tonnage soft insulated pull rod for operation. Effectively solve a series of problems caused by the large deflection of the hard insulated pull rod.


2006 ◽  
pp. 59-70 ◽  
Author(s):  
Milanka Djiporovic ◽  
Jovan Miljkovic ◽  
Eva Dingova

New materials based on wood have the advantage in the sense that their properties can be engineered so as to correspond to user demands. The properties which can be engineered are those relating both to their utilisation and machining, in particular - the tensile strength, elongation at break, modulus of elasticity and impact resistance. The research at the Faculty of Forestry and "Hipol" Chemical Industry related to the new type of wood-polypropylene composite. The content of wood filler was varied in the range between 40% and 70% mass contents of beech wood flour. After the highest tensile strength at 50% of filler content was determined, the effect of the wood filler origin was also examined at this content value. Therefore, wood flour of beech, poplar, acetylated pine and the waste MDF was used. The influence of the composition of the wood filler (beech combined with MDF, poplar and acetylated pine) in comparison with pure polypropylene matrix was also examined, as well as the effect of the type of coupling agent. Hopefully, the results obtained in this study might serve as the initial data for production of easily machined high-strength composites.


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