为了研究炭黑的填充对橡胶材料力学行为的影响,对9种不同体积分数的炭黑填充橡胶材料进行准静态单向拉伸试验,并依据试验数据采用最小二乘法对Mooney橡胶的本构常数进行拟合,然后采用随机序列吸附算法建立更加接近炭黑填充橡胶复合材料真实细观结构的多球颗粒随机分布的三维细观数值模型,对炭黑填充橡胶材料的力学行为进行模拟仿真。研究结果表明,炭黑的填充明显提升了橡胶材料的刚度大小,而且炭黑填充量越大,橡胶的初始模量越大,同一变形量下橡胶的应变能密度越大,应力松弛现象也越明显;炭黑填充量为7%和15%时,细观模型对应力应变行为的预测结果与宏观试验曲线基本重合,炭黑填充量为25%时,细观模型预测结果稍微低于试验结果,说明提出的三维数值模型对炭黑填充橡胶材料力学行为的预测结果与试验结果吻合较好,验证了该模型的合理性和适用性,为进一步的深入研究奠定了基础。
To explore the effect of carbon black on the mechanical behavior of rubber material, 9 kinds of rubbers filled with different volume fraction of carbon black are studied by quasi-static uniaxial tensile test, and the material constants of Mooney rubber are fitted through the least squares methods, then three-dimensional numerical models containing multi-sphere particles randomly distributed are built to simulate the mechanical behavior of carbon black filled rubber composite. The research shows that the stiffness of the rubber composite is increased considerably with the introduction of carbon black filler particles, and the greater the carbon black filler content, the higher the initial modulus of the rubber composite, the greater the strain energy density at the same deformation condition, and the more obvious the stress relaxation phenomenon. With 7 and 15 percent carbon black filler content, the results of the predictions on the stress-strain behavior of the rubber composite made with the microscopic numerical models are consistent well with the macroscopic test curves. With 25 percent carbon black filler content, the results of the predictions with the microscopic numerical models are slightly below the macroscopic test curve. It demonstrates that the predictions on the mechanical behavior of carbon black filled rubber composite made by the three-dimensional numerical model containing multi-sphere particles randomly distributed are in good agreement with the experimental results, which confirms the rationality and adaptability of the proposed model, and these researches provide the basic and scientific information for further research.