The aim of this article was to evaluate and analyze the mechanical properties of bonded elastomer discs subjected to triaxial stress on an MTS (machine for testing samples) equipment. Several pulling tests were run on an Instron machine using an O-ring type of samples to evalutate the mechanical properties of testing unfilled nitrile rubber subjected to uniaxial tension. It was found from the stress-strain curve of the O-ring samples that a very small stress softening occurred when the maximum strain is less than 200%. It was also found that the stress and strain at break does not drastically vary with respect to strain rate. The initial modulus does not vary with respect to strain rate up to epsilon = 2 min(-1), and only for large values of epsilon does the modulus depend on the strain rate. The material used for the uniaxial tension experiments were bonded between two rigid cylindrical steel plates and the specimens were subjected to uniaxial tension on an MTS machine. It was found that the initial modulus in tension was smaller than in compression. The theoretical predicted initial modulus from Gent's equation was much larger than experimentally estimated. It was shown that the elastomer in the pancake tests was not incompressible and a value of 0.494 was determined for the effective Poisson's ratio. A mathematical equation was derived for the effective Poisson's ratio as a function of the volume fraction of voids within the testing material. (C) 1996 John Wiley & Sons, Inc. [References: 23]
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机译：本文的目的是评估和分析在MTS（用于测试样品的机器）设备上经受三轴应力的粘合弹性体圆盘的机械性能。在Instron机器上使用O形圈类型的样品进行了几次拉力测试，以评估未填充丁腈橡胶在单轴张力下的力学性能。从O形圈样品的应力-应变曲线发现，当最大应变小于200％时，发生非常小的应力软化。还发现断裂时的应力和应变相对于应变速率没有显着变化。初始模量不会随应变率变化，直到ε= 2 min（-1），并且仅当ε值较大时，模量才取决于应变率。将用于单轴拉伸实验的材料粘结在两个刚性圆柱钢板之间，并在MTS机器上对样品进行单轴拉伸。发现拉伸的初始模量小于压缩的初始模量。根据根特方程的理论预测初始模量比实验估计的要大得多。结果表明，薄煎饼试验中的弹性体是不可压缩的，有效泊松比值为0.494。推导了有效泊松比作为测试材料中空隙体积分数的函数的数学方程式。 （C）1996 John Wiley＆Sons，Inc. [参考：23]
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