基于改进层间剪切强度准则的层压板冲击分层阈值力预测

Prediction of Delamination Threshold Load for Impact on Composite Laminate Based on Modified Interlaminar Shear Strength Criterion

薄板受冲击时产生的挠度会使接触半径大于直接由赫兹接触定律所得的接触半径。本文提出两种考虑薄板挠度的接触半径修正方法,首先使用赫兹接触定律初步计算接触半径,再联立层压板挠度公式和冲击头表面的几何方程得出修正的接触半径,用有限元模型验证了接触半径修正方法的有效性。使用基于层间剪切强度的分层阈值力(DTL)准则,提出了根据少量测试样本预测不同厚度层压板在不同半径冲击头作用下分层阈值力的方法。使用该方法预测了不同冲击参数下复合材料翼盒蒙皮的低速冲击分层阈值力。结果表明,使用了修正的接触半径后,预测精度有大幅的提高。

The contact radius of thin plates subjected to impacts with great deflection may be larger than that which is directly calculated with the Hertzian contact law.Two methods are proposed to calculate the contact radius with consideration of the deflection of a thin plate.The preliminary contact radius is calculated first based on the Hertzian contact law.The modified contact radius is then obtained by solving the simultaneous equations of a composite laminate’s deflection and the geometry of the impactor.The modification of the contact radius is verified with finite element simulations.The modified contact radius is adopted to set up a new delamination threshold load （DTL） criterion based on the interlaminar shear strength.An approach of DTL prediction for the impact on composite laminates of different thicknesses by different tup diameters using a little test data is proposed based on this criterion.The proposed method is applied to predict the DTL of a low velocity impact on the skin of a composite wing box and it yields more accurate results.