封隔器超弹性胶筒力学性能的试验研究

Experimental Study on Mechanics Properties of Rubber for Packer Sleeve

封隔器的关键元件是超弹性胶筒,当封隔器胶筒座封时,其力学性能的优劣将确定封隔器的密封能力。利用非接触式的光学测量方法——自动网格法进行橡胶试样的变形测量,并利用基于该测量方法而开发的橡胶材料温度相关力学行为测试系统,对封隔器橡胶在不同温度下的力学行为开展试验研究,获得了高精度的拉伸应力—应变曲线。试验结果还表明,随着环境温度的升高,两种封隔器胶筒橡胶材料先表现出明显的软化特征,然后又转变为硬化特征,逆转温度为338 K;这两种橡胶的应变能密度比率也随温度的升高呈现出明显的先下降再上升的转变,转变点温度也为338 K,而迟滞损耗随温度升高均呈线性下降趋势。另外,两种封隔器橡胶的泊松比均接近0.5,可认为是体积不可压缩材料。研究结果为建立封隔器胶筒橡胶的本构关系提供了试验依据。

The key component of a packer is the hyperelastic rubber sleeve.When the packer rubber is settled,its mechanical properties will determine the sealing ability of the packer.In this paper an experimental study on packer rubber material is conducted.A kind of non-contact optical deformation record technique,which is named automatic grid method,is utilized to measure rubber sample deformation under tension loading.Also the experimental setup involves temperature control system.Two kinds of compound material are tested at different temperature environment from room temperature to 338 K,and the stress-strain curves with high precision are obtained.The experiment results demonstrate that with the rise of temperature the stiffness and the ratios of strain energy density of the two rubbers exhibit decreasing first and increasing later with 338 K transition temperature.However,the hysteresis losses of the two rubbers descend linearly with temperature rising.The Poisson ratios of the two rubbers are about 0.5 which means they are nearly incompressible materials.The conclusions provide experimental basis for establishing constitutive relations of packer rubbers.