scholarly journals Dynamic Characteristics of Rubber Powder Modified Cement Asphalt Mortar

2012 ◽  
Vol 5 ◽  
pp. 243-246 ◽  
Author(s):  
Yun Liang Li ◽  
Yang Jian Ou ◽  
Yi Qiu Tan ◽  
Ming Yu Lu
Keyword(s):  
High Speed ◽  
Damping Ratio ◽  
Beam Specimen ◽  
Rubber Powder ◽  
Cement Asphalt Mortar ◽  
Track System ◽  
Vibration Attenuation ◽  
Vibration Tests ◽  
The Impact ◽  
Asphalt Mortar

Cement asphalt mortar (CA) is mainly applied in track system of high-speed railways for vibration attenuation. The impact on dynamics performance of CA with the admixture of rubber powder was studied. The beam specimen made of CA was manufactured for analyzing its vibration frequency and damping characteristics by free attenuation vibration tests. Results showed that there was no big change for fundamental frequency after admixture of rubber powder. However, high order frequency and structural damping increased with the increase of admixture amount. Damping ratio of CA was increased by admixing rubber powder, which can be better for energy absorption and vibration attenuation.

scholarly journals Effect of Water and Emulsifier on the Mechanical Properties of Cement Asphalt Mortar

2019 ◽  
Vol 271 ◽  
pp. 03002
Author(s):  
Tri Ho Minh Le ◽  
Dae-Wook Park ◽  
Jung-Woo Seo
Keyword(s):  
High Speed ◽  
Mechanical Performance ◽  
Strength Development ◽  
Mechanical Degradation ◽  
Asphalt Emulsion ◽  
Term Operation ◽  
Cement Asphalt Mortar ◽  
Rail Structure ◽  
Asphalt Mortar ◽  
Mixing Water

The long-term operation of high-speed railway leads to remarkable issues in ballast mechanical degradation and track irregularity. Particularly, in mainline of rail structure, the required time for ballast layer maintenance is strictly short. To systematically cope with this problem, a comprehensive study was proposed to develop a new cement asphalt mortar (CAM) stabilized ballast method. This solution is expected to improve the ballast structural durability with fast application time. However, the engineer properties of CAM paste with different level of initial mixing water as well as the influencing mechanisms are not clearly understood. In this work, the effects of initial mixing water and emulsifier on the mechanical performance of CAM are mainly discussed. The characteristics of the mortar were determined by conducting the flowability test, mixing stability test, and unconfined compressive strength (UCS) test. The test results revealed that the initial mixing water plays an important role in both fresh and hardened stage of CAM, especially the demulsification process of asphalt emulsion. Meanwhile, the emulsifier imposed a critical effect on the strength development of CAM mixture.

scholarly journals Experimental and Analytical Characterization of Drop Impact Behavior for a Mobile Haptic Actuator

2017 ◽  
Author(s):  
Byungjoo Choi ◽  
Jiwoon Kwon ◽  
Yongho Jeon ◽  
Moon Gu Lee
Keyword(s):  
High Speed ◽  
Damping Ratio ◽  
Free Fall ◽  
Element Model ◽  
Impact Behavior ◽  
Air Resistance ◽  
Impact Reliability ◽  
The Impact ◽  
The Finite Element Model

Impact characterization of linear resonant actuator (LRA) is studied experimentally by newly developed drop tester, which can control various experimental uncertainty such as rotational moment, air resistance, secondary impact and so on. The feasibility of this test apparatus was verified by comparison with free fall test. By utilizing a high-speed camera and measuring the vibrational displacement of spring material, the impact behavior was captured and the damping ratio of the system was defined. Based on the above processes, the finite element model was established and the experimental and analytical results were successfully correlated. Finally, the damage of the system from impact loading can be expected by developed model and as a result, this research can improve the impact reliability of LRA.

Dynamic Analysis of Pitch Plane Railway Vehicle-Track Interactions Due to Single and Multiple Wheel Flats

2008 ◽  
Author(s):  
Rajib Ul Alam Uzzal ◽  
Subhash Rakheja ◽  
Waiz Ahmed
Keyword(s):  
Parametric Study ◽  
High Speed ◽  
Impact Load ◽  
Critical Length ◽  
Hertzian Contact ◽  
Railway Vehicle ◽  
Main Concern ◽  
Track System ◽  
Wheel Flat ◽  
The Impact

The dynamic impact forces due to the wheel defect such as a flat is a main concern for a heavy freight train operating at high speed. The present investigation employs a pitch plane vehicle model coupled with a comprehensive three-layer track system model to study the impact force generated in the wheel-rail interface due to the presence of wheel flats. The wheel-rail contact is modeled using nonlinear Hertzian contact theory. Responses in terms of wheel-rail impact load and forces transmitted to bearings, pad and ballast are evaluated in an attempt to identify desirable design and operating factors. Wheel-rail impact loads due to the presence of multiple flats either in single or different wheels in-phase or out-of-phase conditions are evaluated and analyzed. A detailed parametric study is carried out that includes the variations in selected vehicle, track, operational as well as flat parameters. The results show that the effect of multiple flats is insignificant if they are more than 45° apart. The impact due to single wheel flat can be larger than in-phase flats at each wheel due to the presence of pitch dynamics. The parametric study shows that other than speed, depth and length of the flats are most sensitive parameters, and there exists a critical length at each flat depth that leads to the largest impact load.

Analysis of Dynamic Response of Simply-Supported Girder Bridge in High-Speed Railway Based on the Moving Rows Mass-Spring Model

2012 ◽  
Vol 193-194 ◽  
pp. 919-924
Author(s):  
Jin Feng Wu ◽  
Zhi Jun Zhang ◽  
Xiao Zhen Li
Keyword(s):  
High Speed ◽  
Damping Ratio ◽  
Spring Model ◽  
Simply Supported ◽  
Mass Spring Model ◽  
Girder Bridge ◽  
Set Up ◽  
Mass Spring ◽  
The Impact ◽  
Bridge System

The vibration theory of beam and D’Alembert principle are used to set up vehicle-bridge system for a simply-supported girder bridge under the moving rows mass-spring model. The kinematic equations of vehicle and bridge are derived separately. And with the force balanced relationship and the displacement compatibility conditions between wheels and rail, the equations of vehicle-bridge system are established. A calculating program is complicated with MATLAB language and solved by Newmark-β method. Results show that the effect of the damping ratio on the impact factor is significant and running speed of the vehicle is one of the main actors resulting in vibration of the system.

scholarly journals Cement asphalt mortar for high-speed rail

2020 ◽  
Vol 65 (22) ◽  
pp. 2384-2394
Author(s):  
Dehua Deng ◽  
Qiang Yuan ◽  
Yong Wang
Keyword(s):  
High Speed ◽  
High Speed Rail ◽  
Cement Asphalt Mortar ◽  
Asphalt Mortar

Prepartion and Atypical Mechianical Performance of Epoxy Asphalt Cement Mortars Composite Material for High Speed Railway

2011 ◽  
Vol 90-93 ◽  
pp. 547-553 ◽  
Author(s):  
Xing Long Fang ◽  
Zhi Ming Chen ◽  
Zhen Jiao ◽  
Gang Hua Pan ◽  
Wen Ping Zhou ◽  
...  
Keyword(s):  
Compressive Strength ◽  
High Speed ◽  
Cement Mortar ◽  
Asphalt Emulsion ◽  
Asphalt Cement ◽  
Chemically Modified ◽  
Epoxy Asphalt ◽  
Cement Asphalt Mortar ◽  
Weather Resistance ◽  
Asphalt Mortar

Cement asphalt mortar is a key part of flexible adjusting layer in slab ballastless track structure. In this paper, new materials of epoxy asphalt cement mortar (EACM) was prepared with epoxy and chemically modified asphalt emulsionwhich showed excellent in terms of durability and weather resistance. This paper through changing the proportions of the eopxy-asphalt cement ration studies the relationship among fluidity, compressive strength, and elastic modulus of EACM and cement asphalt mortar (CAM) use chemical modification of asphalt emulsion and normal asphalt emulsion. The results showed that chemically modified epoxy asphalt emulsion cement mortar turned out to be relatively better in compressive strength, frost resistance and weather ability compared with CAM. The chemical reaction mechanism of epoxy asphalt emulsion were investigated by the means of environmental scanning electron microscope (ESEM) method.

Vibration Tests of the Processing Shaft Cascading Structure in High Speed and High Precision PCB Drilling Machine

2012 ◽  
Vol 246-247 ◽  
pp. 1263-1267
Author(s):  
Feng Gong ◽  
Yan Ping Tan ◽  
Ji Bin Li
Keyword(s):  
High Precision ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Drilling Machine ◽  
Guide Rail ◽  
Basic Part ◽  
Free Mode ◽  
Set Up ◽  
Vibration Tests ◽  
The Impact

It is necessary to study the dynamic characteristics of the structure of processing shaft cascade in high speed and high precision PCB drilling machine because of its great impact on the drilling precision. As a basic part, the dynamic characteristics of the structure of cascade depend on the dynamic characteristics of the Z-axis floor. Based on it, firstly, the free mode test is conducted on the Z-axis floor, the same as the modes that it is just set up on the guide rail, the cascade is added and the motor spindle has been added on the Z-axis floor. From the four situations, the modal pa-rameters are gained in the tests. Then the ODS test is carried out and the vibration is analyzed in the real situation. The vibration tests of the cascade comprehensively acquire dynamic characteristics from the Z-axis floor before being assembled to the Z-axis floor which is entirely cascaded on the Z axis. Acknowledge of the impact that the vibrations bring to the drilling precision of the drilling machine provides the direction of improving the structure.

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