不饱和聚酯树脂的单轴应变循环特性和棘轮行为实验研究

EXPERIMENTAL STUDY ON UNIAXIAL STRAIN CYCLIC CHARACTERISTICS AND RATCHETING BEHAVIOR OF UNSATURATED POLYESTER RESIN

  • 摘要: 在室温下,对不饱和聚酯树脂进行了单轴应变控制和应力控制的循环实验研究。讨论了应变幅值对该树脂应变循环特性的影响以及应力幅值、平均应力、应力率、峰值保持时间对其棘轮行为的影响。结果表明:不饱和聚酯树脂在室温下基本上是循环稳定材料,即响应应力幅值在应变循环中基本上不随循环周次而发生变化;在非对称应力循环下,其棘轮行为不仅受平均应力、应力幅值的影响,还受应力率和峰值保持时间的影响,体现出明显的时间相关性。

     

    Abstract: An experimental study was carried out for the cyclic deformation behavior of polyester resin subjected to uniaxial strain or stress-controlled cyclic tension-compression loading. The effect of applied strain amplitude on the strain cyclic characteristics was studied. In the mean time, under the asymmetrical uniaxial stress-controlled cyclic tension-compression loading, the ratcheting behavior of the resin and its dependences upon the applied stress amplitude, mean stress, stress rate and peak stress hold were also discussed. It is shown that the resin is basically a kind of cyclic stable materials, and the responded stress amplitude keeps almost unchanged during the strain-controlled cyclic tension-compression loading. Apparent ratcheting behavior occurs in the resin under the uniaxial asymmetrical stress-controlled cyclic tension-compression loading and the ratcheting strain increases obviously with the increases of the applied stress amplitude, mean stress and the time of peak stress hold, but decreases with the increase of stress rate. The ratcheting of the resin has great time-dependence, which is caused by the significant viscosity of the resin.

     

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