A new nonlinear model to describe the degradation law of the mechanical properties of lead‐rubber bearings under high‐speed horizontal loading

2021 ◽  
Author(s):  
Yanhui Liu ◽  
Weijian Zhong ◽  
Oya Mercan ◽  
Ping Tan ◽  
Fulin Zhou
Keyword(s):  
Mechanical Properties ◽  
Nonlinear Model ◽  
High Speed ◽  
Horizontal Loading ◽  
Lead Rubber Bearings ◽  
Rubber Bearings

Nonlinear Model for Lead–Rubber Bearings Including Axial-Load Effects

2005 ◽  
Vol 131 (12) ◽  
pp. 1270-1278 ◽  
Author(s):  
Keri L. Ryan ◽  
James M. Kelly ◽  
Anil K. Chopra
Keyword(s):  
Nonlinear Model ◽  
Axial Load ◽  
Lead Rubber Bearings ◽  
Load Effects ◽  
Rubber Bearings

Study on Seismic Isolation of High-Speed Railway Bridge Fabricated Lead Rubber Bearings

2011 ◽  
Vol 80-81 ◽  
pp. 409-413 ◽  
Author(s):  
Huan Tang ◽  
Hui Wang ◽  
Biao Zhou ◽  
Ling Kun Chen
Keyword(s):  
High Speed ◽  
Seismic Isolation ◽  
Computational Method ◽  
Bridge Engineering ◽  
Design Parameters ◽  
Vehicle Speed ◽  
Widespread Application ◽  
Bridge Model ◽  
Lead Rubber Bearings ◽  
Rubber Bearings

Lead rubber bearings (LRB) is a new type of earthquake-resistance rubber bearings, formed by inserting lead-core into ordinary laminated rubber bearings, vertical supporting, horizontal displacement and hysteretic damping are hung in single unit together. Because lead-core can dissipate seismic energy and increase stiffness under load simultaneously, most of the requirements of the Seismic isolation system can be satisfied , the material-device has been found widespread application prospect in bridge Engineering. Equivalent linear model of hysteretic characteristics, computational method and the varying range of design parameters of LRB are presented. A full-bridge model of multi-span simple supported bridge with LRB is established in which box beam、LRB and piers are taken into account as a whole. By changing the property of earthquake excitation, ground motion intensity, vehicle speed and so on, the response of Bridge vibration system are analyzed, response law and characteristics of Bridge with LRB under different excitations are investigated systematically, compared with bridge with common bearings.

Evaluation of Long-Term Behavior by the Size of Lead Rubber Bearings

2016 ◽  
Author(s):  
Junhee Park ◽  
Young-Sun Choun ◽  
Min Kyu Kim
Keyword(s):  
Mechanical Properties ◽  
Thermal Oxidation ◽  
Effective Stiffness ◽  
Design Stage ◽  
Seismic Force ◽  
Lead Rubber Bearings ◽  
Rubber Bearings ◽  
Long Term Behavior ◽  
Outside Diameter

In the nuclear power plants (NPPs), the base isolators can be used to decrease the seismic force (acceleration, shear force, floor response spectra). During the lifetime of isolation systems, the mechanical properties of rubber bearings will be constantly changed by the vulcanization and degradation of the rubber due to environmental and chemical factors such as the thermal oxidation, ultraviolet irradiation, and ozone. Usually, thermal oxidation is the most significant degradation factors during the lifetime of natural rubber. Thermal oxidation hardens the rubber and results in a significant decrease in performance. It was presented that the stiffness was increased and damping was decreased by the aging of lead rubber bearings (LRB). It can be observed that the horizontal stiffness of rubber bearings increases about 10% after 15 to 40 years. Considering aging effect of bearings at the design stage, AASHTO [1999] suggested an aging factor for the post-yield stiffness in LRBs. The aging of LRB may be proceeded from the surface to internal because the aging of rubber bearings mainly affected by the oxidation. Therefore, the long-term behavior of LRB can different according to the size. In this study, the horizontal stiffness and damping was evaluated by the size of LRB using the analytical model. The LRBs with an outside diameter of 250 mm (D-250) and an outside diameter of 1,500 mm (D-1500) were selected as example model. In this study, Yeo model was used to model the properties of rubber material and ABAQUS was used as the analysis program. Aging depth of LRB was assumed to be 11 mm and 16 mm based on the accelerated thermal oxidation test. From the analysis result, the effective stiffness of LRB of D-250 was increased about 15%∼22% while the effective stiffness of LRB of D-1500 was increased about 4%∼9%. Although the aging depth of LRB was equal, the ratio aging area to total area of LRB was different according to the size of bearings. Therefore, the mechanical properties factors should be proposed considering the size of LRB.

Influence of ageing treatment on microstructure, mechanical properties and adhesive wear behaviour of 6063 aluminium alloy

2014 ◽  
Vol 66 (4) ◽  
pp. 520-524 ◽  
Author(s):  
Serkan Büyükdoğan ◽  
Süleyman Gündüz ◽  
Mustafa Türkmen
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
High Speed ◽  
Al Alloys ◽  
Wear Behaviour ◽  
Al Alloy ◽  
Strain Ageing ◽  
Content Type ◽  
Static Strain ◽  
Structural Applications

Purpose – The paper aims to provide new observations about static strain ageing in aluminium (Al) alloys which are widely used in structural applications. Design/methodology/approach – The present work aims to provide theoretical and practical information to industries or researchers who may be interested in the effect of static strain ageing on mechanical properties of Al alloys. The data are sorted into the following sections: introduction, materials and experimental procedure, results and discussion and conclusions. Findings – Tensile strength, proof strength (0.2 per cent) and percentage elongation measurement were used to investigate the effect of strain ageing on the mechanical properties. Wear tests were performed by sliding the pin specimens, which were prepared from as-received, solution heat-treated, deformed and undeformed specimens after ageing, on high-speed tool steel (64 HRC). It is concluded that the variations in ageing time improved the strength and wear resistance of the 6063 Al alloy; however, a plastically deformed solution-treated alloy has higher strength and wear resistance than undeformed specimens for different ageing times at 180°C. Practical implications – A very useful source of information for industries using or planning to produce Al alloys. Originality/value – This paper fulfils an identified resource need and offers practical help to the industries.

scholarly journals Fiber Formation and Structural Development of HBA/HNA Thermotropic Liquid Crystalline Polymer in High-Speed Melt Spinning

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1134
Author(s):  
Bo Seok Song ◽  
Jun Young Lee ◽  
Sun Hwa Jang ◽  
Wan-Gyu Hahm
Keyword(s):  
Mechanical Properties ◽  
Shear Rate ◽  
High Speed ◽  
Melt Spinning ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Fiber Formation ◽  
Structural Development ◽  
Thermotropic Liquid Crystalline Polymer

High-speed melt spinning of thermotropic liquid crystalline polymer (TLCP) resin composed of 4-hydroxybenzoic acid (HBA) and 2-hydroxy-6-napthoic acid (HNA) monomers in a molar ratio of 73/27 was conducted to investigate the characteristic structure development of the fibers under industrial spinning conditions, and the obtained as-spun TLCP fibers were analyzed in detail. The tensile strength and modulus of the fibers increased with shear rate in nozzle hole, draft in spin-line and spinning temperature and exhibited the high values of approximately 1.1 and 63 GPa, respectively, comparable to those of industrial as-spun TLCP fibers, at a shear rate of 70,000 s−1 and a draft of 25. X-ray diffraction demonstrated that the mechanical properties of the fibers increased with the crystalline orientation factor (fc) and the fractions of highly oriented crystalline and non-crystalline anisotropic phases. The results of structure analysis indicated that a characteristic skin–core structure developed at high drafts (i.e., spinning velocity) and low spinning temperatures, which contributed to weakening the mechanical properties of the TLCP fibers. It is supposed that this heterogeneous structure in the cross-section of the fibers was induced by differences in the cooling rates of the skin and core of the fiber in the spin-line.

scholarly journals Enhanced electrical conductivity and mechanical properties in thermally stable fine-grained copper wire

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Qingzhong Mao ◽  
Yusheng Zhang ◽  
Yazhou Guo ◽  
Yonghao Zhao
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Electrical Conductivity ◽  
Yield Strength ◽  
High Speed ◽  
Copper Wire ◽  
Rapid Development ◽  
Dislocation Slip ◽  
Ultrafine Grains ◽  
The Wire

AbstractThe rapid development of high-speed rail requires copper contact wire that simultaneously possesses excellent electrical conductivity, thermal stability and mechanical properties. Unfortunately, these are generally mutually exclusive properties. Here, we demonstrate directional optimization of microstructure and overcome the strength-conductivity tradeoff in copper wire. We use rotary swaging to prepare copper wire with a fiber texture and long ultrafine grains aligned along the wire axis. The wire exhibits a high electrical conductivity of 97% of the international annealed copper standard (IACS), a yield strength of over 450 MPa, high impact and wear resistances, and thermal stability of up to 573 K for 1 h. Subsequent annealing enhances the conductivity to 103 % of IACS while maintaining a yield strength above 380 MPa. The long grains provide a channel for free electrons, while the low-angle grain boundaries between ultrafine grains block dislocation slip and crack propagation, and lower the ability for boundary migration.

scholarly journals Texture and mechanical properties of Cu alloy by cryogenic high-speed rolling

2021 ◽  
Vol 1121 (1) ◽  
pp. 012009
Author(s):  
S Lee ◽  
R Muchime ◽  
R Matsumoto ◽  
H Utsunomiya
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
Cu Alloy

scholarly journals Prey Capturing Dynamics and Nanomechanically Graded Cutting Apparatus of Dragonfly Nymph

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 559
Author(s):  
Lakshminath Kundanati ◽  
Prashant Das ◽  
Nicola M. Pugno
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
High Speed ◽  
Prey Capture ◽  
High Speed Photography ◽  
Sensory Organs ◽  
Dragonfly Nymph ◽  
Drag Forces ◽  
Predatory Insects ◽  
Dragonfly Nymphs

Aquatic predatory insects, like the nymphs of a dragonfly, use rapid movements to catch their prey and it presents challenges in terms of movements due to drag forces. Dragonfly nymphs are known to be voracious predators with structures and movements that are yet to be fully understood. Thus, we examine two main mouthparts of the dragonfly nymph (Libellulidae: Insecta: Odonata) that are used in prey capturing and cutting the prey. To observe and analyze the preying mechanism under water, we used high-speed photography and, electron microscopy. The morphological details suggest that the prey-capturing labium is a complex grasping mechanism with additional sensory organs that serve some functionality. The time taken for the protraction and retraction of labium during prey capture was estimated to be 187 ± 54 ms, suggesting that these nymphs have a rapid prey mechanism. The Young’s modulus and hardness of the mandibles were estimated to be 9.1 ± 1.9 GPa and 0.85 ± 0.13 GPa, respectively. Such mechanical properties of the mandibles make them hard tools that can cut into the exoskeleton of the prey and also resistant to wear. Thus, studying such mechanisms with their sensory capabilities provides a unique opportunity to design and develop bioinspired underwater deployable mechanisms.

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