scholarly journals Use of Rubber Mat to Improve Deformation Behaviors of Ballastless Tracks Laid on Bridges

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Weiqi Zheng ◽  
Xingwang Sheng ◽  
Hongqiang He ◽  
Hongyi Xu ◽  
Ying Yang
Keyword(s):  
Static Load ◽  
Tensile Deformation ◽  
Service Condition ◽  
Isolation Layer ◽  
Ballastless Track ◽  
Routine Service ◽  
Different Types ◽  
Rubber Mat ◽  
Deformation Behaviors ◽  
Loading Tests

The deformation behaviors of ballastless tracks have an important influence on their service performance. In this work, rubber mats commonly used in metro traffic were employed in ballastless tracks laid on bridges to improve their deformation behaviors. In order to research the effect of rubber mat for deformation behaviors, a series of static loading tests were carried out based on two full-scale ballastless tracks with different types of isolation layers. Main conclusion include that, for ballastless track with geotextile isolation layers, gaps and voids are formed at interlayers with the increasing static load. However, for ballastless track with rubber mat isolation layer, the maximum tensile deformation in the thickness direction unexceeds the precompression of rubber mat under the deadweight of its upper structures. Interlayer gaps and voids can be eliminated due to the precompression of rubber mat. Besides, the rubber mat isolation layer is still in the linear elasticity stage under the routine service condition, and the interlayer behaviors of the ballastless tracks perform well. It is a feasible way to use a rubber mat isolation layer to improve the deformation behaviors of ballastless tracks laid on bridges.

scholarly journals Rheological Solidification Behavior and Mechanical Properties of AZ91-Sn Alloys

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 641 ◽  
Author(s):  
Di Tie ◽  
Boyu Zhang ◽  
Lufei Yan ◽  
Renguo Guan ◽  
Zhaoshan Ji ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Deformation ◽  
Eutectic Reaction ◽  
Az91 Alloy ◽  
Solidification Behavior ◽  
Magnesium Matrix ◽  
Solid Solution Strengthening ◽  
The Matrix ◽  
Deformation Behaviors ◽  
Solution Strengthening

The solidification and tensile deformation behaviors of rheo-cast AZ91-Sn alloys were revealed to study the effects of Sn alloying on improvement of AZ91 alloy’s mechanical properties. Two kinds of Mg17Al12 phases precipitated from the supersaturated magnesium matrix during rheo-solidification were observed: coarse discontinuous precipitates (DP) at grain boundaries and small-sized continuous precipitates (CP) inside grains. With increasing Sn content, the amount of Mg17Al12 phases was increased whilst the amount of Al atoms in the matrix was decreased. Due to the higher melting point of Mg2Sn than Mg17Al12, Mg2Sn precipitated earlier from the melt, and therefore provided heterogeneous nuclei for Mg17Al12 during the eutectic reaction. Due to grain refinement and solid solution strengthening, AZ91-2.4Sn (mass%) gained 52% increase in tensile strength and 93% increase in elongation compared with pure AZ91 alloy. The higher-density twins and microcracks induced by Sn alloying relaxed stress concentration during plastic deformation, so the fracture mode was transformed from cleavage fracture of pure AZ91 alloy to ductile fracture of AZ91-Sn alloys.

scholarly journals Influence of Local Deformation Mode of Cable-Stayed Bridge on Unballasted Tracks: Experimental Research

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Xingwang Sheng ◽  
Weiqi Zheng ◽  
Jianxian Wu ◽  
Handong Zhang
Keyword(s):  
Large Scale ◽  
Deformation Mode ◽  
Local Deformation ◽  
Deformation Characteristics ◽  
Isolation Layer ◽  
Segment Model ◽  
Cable Stayed Bridge ◽  
Deformation Behaviors ◽  
Nonlinear Behaviors ◽  
Deformation Modes

The complex local deformation modes of the cable-stayed bridge influence the deformation characteristics of the unballasted tracks laid on it. In this work, a large-scale segment model of a cable-stayed bridge was fabricated, and the maximum upward bending deformation mode of the cable-stayed bridge was realized by multipoint loading on the segment model to study the deformation behaviors of the unballasted tracks. Experimental results indicated that the nonlinear behaviors of the rubber isolation layers are apparent with the loading increased, and the interlayer behaviors of the unballasted track can be improved by the rubber isolation layer. Besides, the relative tensile deformations at interlayers of the unballasted track are inevitable. It is noted that no void and silt form at interlayers of the unballasted tracks with rubber isolation layers due to the precompressions of the rubber material. However, it is entirely possible to produce some diseases such as voids and silts at interlayers of the unballasted track with the geotextile isolation layers paved on the cable-stayed bridge. Furthermore, it is feasible to use the elastic isolation layer to improve the interlayer deformation characteristics because a particular elastic buffer is provided at interlayers of the unballasted track.

Tensile Deformation Behaviors in a Fine-Grained, Rolled Mg-3Al-3Sn Alloy at Room Temperature up to 250 °C

2014 ◽  
Vol 17 (2) ◽  
pp. 199-204 ◽  
Author(s):  
Xiao-Long Nan ◽  
Hui-Yuan Wang ◽  
Jian Rong ◽  
En-Song Xue ◽  
Guo-Jun Liu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Tensile Deformation ◽  
Fine Grained ◽  
Deformation Behaviors

scholarly journals Postural Behaviour in Gilts Housed on Concrete and Rubber Slats During four Seasons

2014 ◽  
Vol 37 (2) ◽  
pp. 157-164 ◽  
Author(s):  
Željko Pavičić ◽  
Mario Ostović ◽  
Sven Menčik ◽  
Anamaria Ekert Kabalin ◽  
Marija Vučemilo ◽  
...  
Keyword(s):  
Thermal Conditions ◽  
Group Differences ◽  
Experimental Animals ◽  
Service Unit ◽  
Four Seasons ◽  
Study Results ◽  
Different Types ◽  
Rubber Mat ◽  
Production Cycles ◽  
Experimental Group

AbstractIn the present study, postural behaviour was compared between gilts kept in service unit with different types of flooring during all seasons. The study included four 28-day production cycles and 10 gilts per cycle, equally divided into a control and an experimental group. Control gilts were housed in gestation stalls with slatted concrete floor, whereas in the experimental group the floor was covered with an adjusted rubber mat. Postural behaviour of gilts was observed 4 times per cycle for 4 hours. Study results showed that during cooler seasons, gilts in concrete stalls spent more time standing and lying sternally, whereas gilts in matted stalls were mostly lying, predominantly laterally (P<0.001 all). There were no significant between group differences according to the time the gilts spent sitting or the frequency of changing posture in any season observed. Nevertheless, experimental animals spent significantly less time changing standing to both lying positions during all seasons (P<0.01 all). In conclusion, rubber mats may improve lying comfort in gilts; however, when using rubber mats, the house thermal conditions should be taken in consideration.

Hot Tensile Deformation Behaviors of an AISI 316LN Stainless Steel

2015 ◽  
Vol 817 ◽  
pp. 367-373
Author(s):  
Xiao Ya Yang ◽  
Xi Tao Wang ◽  
Gen Qi Wang
Keyword(s):  
Experimental Data ◽  
Stainless Steel ◽  
Strain Rate ◽  
Deformation Temperature ◽  
Tensile Deformation ◽  
Deformation Condition ◽  
Percentage Reduction ◽  
Deformation Behaviors ◽  
Hot Tensile Deformation ◽  
Reduction Of Area

The hot tensile deformation behaviors of 316LN austenitic stainless steel (ASS) were studied on a Gleeble-1500D thermal simulator under the deformation temperature of 1173-1473 K and strain rate of 0.01-1 s-1. The effects of deformation temperature and strain rate on hot deformation behaviors were analyzed. Based on experimental data, the constitutive equation was established, and the predicted peak stresses by the developed model agree well with the experimental data. Microstructure near the fracture and the percentage reduction of area were studied, and the results showed that the microstructural evolution has great influences on the percentage reduction of area. Under the deformation temperature of 1473K with the strain rate of 1s-1, the grain was the finest and most homogenous, and in this deformation condition the percentage reduction of area was the highest of 79.8%.

Melt mixed compatibilized polypropylene/clay nanocomposites. II. Dispersion vs. thermal properties, optical transmittance, and fracture behaviors

2011 ◽  
Vol 45 (25) ◽  
pp. 2613-2631 ◽  
Author(s):  
S.-M. Lai ◽  
W.-C. Chen ◽  
X. S. Zhu
Keyword(s):  
Maleic Anhydride ◽  
Clay Content ◽  
Interlayer Spacing ◽  
Optical Transmittance ◽  
Clay Nanocomposites ◽  
Melt Mixing ◽  
Polyolefin Elastomer ◽  
Fracture Behaviors ◽  
Different Types ◽  
Deformation Behaviors

Compatibilized polypropylene (PP)/clay nanocomposites using two different types of maleated compatibilizers, polyolefin elastomer-grafted maleic anhydride (POE- g-MA) and PP-grafted maleic anhydride (PP- g-MA), to improve the dispersion of various amounts of commercial organoclay (Closite 20 A) were prepared via a melt-mixing technique. The optical transmittance for the POE- g-MA compatibilized nanocomposites was lower than that of PP- g-MA compatibilized cases, although POE- g-MA greatly increased the interlayer spacing of the clay compared with PP- g-MA. The optical transmittance of POE- g-MA compatibilized cases increased with increasing clay content, as a result from a preferentially POE- g-MA adsorbed onto the surface and edge of clay moiety. PP- g-MA compatibilized system conferred higher tensile strength, Young's modulus, or cutting strength through crystalline yielding effect even at the nanofracture zone of deformation, but lower tear strength than POE- g-MA compatibilized system. The current results suggested that high extent of exfoliation may not guarantee high transparency or strength varied with different deformation behaviors.

Elastic and Plastic Deformation Behaviors of Lotus-Type Porous Copper

2010 ◽  
Vol 658 ◽  
pp. 332-335
Author(s):  
Masakazu Tane ◽  
Hideo Nakajima
Keyword(s):  
Plastic Deformation ◽  
Acoustic Emission ◽  
Tensile Deformation ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Resonant Ultrasound Spectroscopy ◽  
Porous Copper ◽  
Deformation Behaviors ◽  
Resonant Ultrasound ◽  
Elastic And Plastic Deformation

The elastic and plastic deformation behaviors of lotus-type porous copper (lotus copper) with cylindrical pores oriented in one direction were investigated using two acoustic methods (resonant ultrasound spectroscopy and acoustic emission method). All the independent components of elastic stiffness were determined by resonant ultrasound spectroscopy combined with electromagnetic acoustic resonance method, which revealed that the Young’s modulus exhibits the anisotropy originating from the anisotropic porous structure and anisotropic matrix texture. The porosity dependence of the anisotropic Young’s modulus can be calculated by the micromechanics modeling based on effective-mean-field theory. The tensile deformation behavior of lotus copper was analyzed by acoustic emission method, which revealed that many burst acoustic emission signals are detected during the tensile deformation. This implies that many cracks are formed during the tensile deformation.

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