不同温度下有机玻璃厚板的准静态拉伸试验研究

Quasi-static tensile test of thick acrylic sheets at different temperatures

为研究温度对有机玻璃厚板准静态拉伸力学性能的影响,得到有机玻璃的本构关系,设计了母材试件和带拼接缝试件,分别进行单轴拉伸试验,试验温度为-40~40℃.对比试件的真实和名义应力应变曲线,采用ZWT模型的非线性弹性部分表达式对试验结果进行拟合,并且对试件断口进行电镜扫面分析.试验结果表明,有机玻璃厚板的应力应变曲线表现出非线性,无屈服点,试件为脆性破坏.随着温度的升高,试件的极限强度和初始弹性模量均减小.带拼接缝试件的强度为母材试件强度的77.2%~89.6%.设计的有机玻璃试件强度较高,初始弹性模量偏小.拟合得到的本构方程能较好地描述有机玻璃厚板的本构关系.当温度高于0℃时,断口表面的河流花样变得明显.

In order to study the effects of the temperature on the quasi-static tensile mechanical behavior of thick acrylic sheets and achieve the constitutive relationship of acrylic,the base-material specimens and the specimens w ith joint areas are designed and tested under uniaxial tension. The temperature varies from-40 to 40 ℃. The true stress-strain curves and the nominal ones are compared. The test results are fitted by using the nonlinear elastic expression of the ZWT model. The scanning electron microscope analysis is conducted for the fracture surfaces of the specimens. The test results show that the stress-strain curves of the thick acrylic sheets are nonlinear. There is no yield point and the failures of the specimens are brittle. The ultimate strengths and the initial elastic moduli of the specimens decrease with the increase of the temperature. The strengths of the specimens with joint areas are 77. 2% to 89. 6% of those of the base-material specimens. The strengths of the designed specimens are high,while the initial elastic moduli are low. The constitutive equations obtained by fitting can describe the constitutive relationship of the thick acrylic sheets. When the temperature is higher than 0 ℃,the river patterns of the fracture surfaces become remarkable.