The aim of this work is to investigate the mechanical behavior of a soft matrix reinforced by a single family of parallel fibers subjected to simple shear. Specimens with fibers oriented at −45° with respect to the applied shear load were tested. The shear and normal stress components as well as the amount of shear were simultaneously measured. Due to the initial orientation, fibers were subjected to compressive loads, resulting in buckling. The positive Poynting effect was observed when soft materials were sheared. The off-axis stiffness theory and the Murphy model at small deformations were used to predict the mechanical behavior of the soft composites. In general, there is a reasonable correlation between model predictions and measured data by adjusting only one empirical parameter. However, the model based on the off-axis stiffness shows better prediction than the Murphy model for relatively higher fiber volume fractions. From universal relations for simple shear, the results indicate that the studied composites are of a coaxial type in a weak sense.

这项工作的目的是研究由单族平行纤维增强的软基体在简单剪切下的机械性能。测试了纤维相对于施加的剪切载荷以 -45° 取向的样品。同时测量剪切和法向应力分量以及剪切量。由于初始取向，纤维受到压缩载荷，导致屈曲。当剪切软材料时观察到正坡印廷效应。偏轴刚度理论和小变形下的墨菲模型用于预测软复合材料的机械性能。通常，通过仅调整一个经验参数，模型预测和测量数据之间存在合理的相关性。然而，对于相对较高的纤维体积分数，基于离轴刚度的模型显示出比墨菲模型更好的预测。从简单剪切的普遍关系来看，结果表明所研究的复合材料属于弱意义上的同轴型。