国产F-12芳纶织物面内剪切性能

Experimental investigation of in-plane shear performance for F-12 aramid fabric

对国产F-12芳纶织物的剪切性能进行了研究,通过像框剪切试验和偏轴拉伸试验对其进行了测试,设计了相应的像框剪切夹具,利用数字图像相关方法(DIC)采集织物加载过程的变形场,获得了剪切载荷-剪切角度的变化曲线和剪切锁紧角,通过正则化处理对两种测试结果进行了对比分析;利用数值方法对织物剪切性能进行了计算,建立了一种非正交各向异性的杆-壳模型用于模拟织物剪切变形,编制了VUMAT子程序用于计算纱线方向的改变和应力更新,通过与试验结果的对比验证了计算模型的准确性。结果表明:织物的剪切行为具有明显的非线性特征,试样夹持部分的结构形式会对试验结果产生影响,未抽丝试样的剪切载荷明显大于抽丝试样的剪切载荷,二者的剪切锁紧角近似相等;正则化处理后,相框剪切的剪切载荷大于偏轴拉伸的剪切载荷,而锁紧角小于偏轴拉伸的锁紧角;试验结果与仿真结果对比,仿真结果与试验结果吻合较好。

The in-plane shear performance for F-12 aramid fabric was investigated.The picture frame test and biastensile test were conducted.A new picture clamp was designed.The deformation field of fabric during the test was measured by digital image correlation（DIC）technique.The shear force vs.shear angle curves and the locked angle were obtained.Normalized method was used to compare the two experimental results.Then,numerical method was used to compute the shear characters.A non-orthogonal anisotropic truss-shell model was established to simulate the bias-tensile test.A user defined material subroutine was developed to calculate the direction of the yarns and stress updated.To verify the validity of the model,the simulated results were compared with experimental results.The test results show that the shear performance of the fabric is non-linear.The clamping arm can affect the test results.The force of no silts sample is larger than that of infinite slits sample.The locked angles of these two samples are equal.After normalized,the force of picture frame test is larger than that of bias-tensile test,while the locked angle is smaller.The FEM results agree well with experimental results.