X-cor夹层复合材料平压性能分析

Compression Property Analysis of X-cor Sandwich Composites

X-cor夹层复合材料是一种采用X形Z-pin增强的新型泡沫夹层结构,在航空航天领域有着广阔的应用前景。本文对其平压模量和强度进行了理论预测和实验验证。通过分析其三维单胞力学模型,得到了X-cor夹层复合材料等效平压模量的解析式。采用Winkler弹性地基梁理论解释了泡沫芯材与Z-pin的协同增强效应,并导出了X-cor平压强度的预测公式。以碳纤维/环氧树脂制备的Z-pin分别植入PU,PMI泡沫制得X-cor夹层复合材料,通过力学实验考察了Z-pin参数以及泡沫性能等对X-cor夹层结构平压性能的影响,对理论分析进行了验证。结果证明增大Z-pin的植入角度、体积分数、直径、端部约束或采用高性能泡沫芯材均能提高X-cor平压性能,但增大长度,Z-pin容易失稳,平压强度降低。

X-cor sandwich,a novel composite reinforced by Zpins of X shape,can be applied in aeronautical and astronautical fields.In this article,analytical and experimental studies are carried out to examine the out-of-plane compression properties of X-cor sandwich panel.An analytical formula of equivalent out-of-plane compression modulus is derived by investigating the three dimensional model of X-cor single cell.The compression strength of X-cor is governed by the elastic buckling of Z-pin behaving as beam-column on an Winkler elastic foundation.Therefore the cooperating effects between foam and Z-pin are explained and the compression strength is predicted,and the analytical prediction rule is consistent with measured results.By means of embedding Z-pins made from CF/Epoxy in PU and PMI foams,X-cor sandwiches are prepared.Experimental results show that the out-of-plane compression property is improved by increasing the angle between Z-pin and face sheet,Z-pin＇s volume fraction,diameter,restriction of their ends as well as foam property.But with Z-pin getting longer,it is easier to lose stability,and the compression strength is lower.