Elastomers and Composites

The Rubber Society of Korea (한국고무학회)
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Evaluation of Static Spring Constant and Accelerated Life Prediction for Compression Set of Polyurethane Resilient Pad in Rail Fastening System

  • Lee, Seung-Won (Environmental Materials R&D Center, Materials Technology R&D Division, Korea Automotive Technology Institute) ;
  • Park, Jun-Young (Environmental Materials R&D Center, Materials Technology R&D Division, Korea Automotive Technology Institute) ;
  • Park, Eun-Young (Environmental Materials R&D Center, Materials Technology R&D Division, Korea Automotive Technology Institute) ;
  • Ryu, Sung-Hwan (Environmental Materials R&D Center, Materials Technology R&D Division, Korea Automotive Technology Institute) ;
  • Bae, Seok-Hu (Environmental Materials R&D Center, Materials Technology R&D Division, Korea Automotive Technology Institute) ;
  • Kim, Nam-Il (Environmental Materials R&D Center, Materials Technology R&D Division, Korea Automotive Technology Institute) ;
  • Yun, Ju-Ho (Environmental Materials R&D Center, Materials Technology R&D Division, Korea Automotive Technology Institute) ;
  • Yoon, Jeong-Hwan (Environmental Materials R&D Center, Materials Technology R&D Division, Korea Automotive Technology Institute)
  • Received : 2018.11.20
  • Accepted : 2018.11.26
  • Published : 2018.12.31
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Abstract

Resilient pads play a major role in reducing the impact of loads on a rail in a rail-fastening system, which is essentially used for a concrete track. Although a compression set test is commonly used to measure the durability of a resilient pad, the static spring constant is often observed to be different from the fatigue test. In this study, a modified compression set test method was proposed to monitor the variations in the compression set and static spring constant of a resilient pad with respect to temperature and time. In addition, the life of the resilient pad was predicted by performing an acceleration test based on the Arrhenius equation.

Keywords

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Figure 1. Methods for static spring constant measurement: (a) Standard method for resilient pad; (b) Modified method for specimens after compression aging.

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Figure 2. Load-displacement curve of the specimen measured by standard method.

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Figure 3. Load-displacement curves of the specimen after compression aging: (a) to (c) are 4th cycle curves measured by standard method; (d) to (f) are curves measured by modified method.

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Figure 4. Increase rate of spring constant and compression set after compression aging for time and temperature: (a) at 70℃; (b) at 85℃; (c) at 100℃.

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Figure 5. Variation of property for ln(h) at 70℃, 85℃ and 100℃.

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Figure 6. Arrhenius plots for spring constant increases of 10%.

Table 1. Load Values for Static Spring Constant Measurement

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Table 2. Static Spring Constants for Compression aging

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Table 3. Relationship between Variation of Property and ln(h)

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Table 4. Arrhenius Equations as a Function of Temperature and Useful Life Prediction at using Temperatures

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References

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