缝纫泡沫夹芯复合材料失效强度的理论预测与试验验证

Theoretical prediction and experimental study of the failure strength of stitched foam-core sandwich composites

基于经典层板理论和细观力学桥联模型,提出了缝纫泡沫夹芯复合材料失效强度的理论预测方法,并进行了失效强度的相关试验验证。其中,将缝纫复合材料面板看作单层组成的准层状结构,采用经典层板理论进行逐层失效分析,并同时考虑了局部皱曲的面板失效模式;而对缝纫泡沫夹芯,引入桥联模型计算其各组分材料中的应力,并通过对各组分材料选取适当失效准则来建立失效判据;对于缝纫泡沫夹芯复合材料采取逐级加载方式,当面板或者夹芯失效时,则认为其发生整体失效,由此可以确定其在不同载荷形式下的失效强度。此外,通过试验得到了缝纫泡沫夹芯复合材料板试件在平压、侧压、横向剪切及三点弯曲载荷形式下的失效模式及其失效强度,并利用本文方法对缝纫泡沫夹芯复合材料的失效强度进行了理论预测,所得结果与试验吻合,证明了本文方法的有效性。

Based on the classical laminate theory and bridging micromechanics model,a failure strength prediction method was established for the stitched foam-core sandwich composites.As a quasi layered structure,the composite face-panels were analyzed by the classical lamination theory for layer-by-layer breakage,and the local wrinkling failure of the face-panel was considered.A bridging model was adopted for stress analysis of the stitched foam core,and a strength prediction method was provided by selecting proper failure criteria for different constitutive materials.The failure of the composite was determined by the failure of the face panel or the stitched foam core,and then the failure strength under different loadings was obtained by gradual loading.The failure modes and failure strength of stitched foam-core sandwich composite panels under flat-wise loading,edge-wise loading,three point bending or transverse shear loading were calculated,and the predictive strength results are in good agreement with the experimental data,which demonstrates the validity of the present analytical model.