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以聚氨酯弹性体钢夹层板为研究对象,对其进行了三点弯曲实验,对不同类型试件的实验结果进行了总结.实验发现,在加载过程中,在弯曲挠度超过一定程度时,夹层板结构的角点位置出现开裂,由于层间强度不足和夹心材料的粘弹性性质,卸载后裂纹会在一段时间内沿层间继续发生扩展,最后导致整个面板发生脱粘或夹心撕裂.针对这一现象,以弹性地基梁理论为基础,计算了上下面板的挠度差异,并使用层间粘结强度来分析试件的临界状态,获得了软夹芯试件和硬夹芯试件的临界破坏的裂纹长度.结果表明,使用层间粘结强度分析方法,获得的结果都能够描述聚氨酯弹性体钢夹层板的层间延迟破坏的特点.“,”The Sandwich plate system (SPS) with steel faceplates and polyurethane (PU) elastomer core is a new type of composite which is wildly used in shipbuilding and civil engineering.Lightweight,high strength,excellent fatigue resistance and good workability enable more application prospects for SPS.Debonding is one of the main failure modes of SPS under bending,and interface strength is the key factor in determining the flexural strength.In this study,three-point bending tests were carried out to investigate the bending performance of SPS.Different failure modes were obtained and discussed with different ways of manufacture.It was observed from the bending tests that when the deflection exceeded a certain range,cracks began to appear in the loading process,leading to the debonding of the entire interface between faceplates and polyurethane core in the unloading process that followed.Because of the viscoelastic characteristics and lower interface strength of the PU core,debonding did not happen immediately after the tests,i.e.it took a period of time before the upper faceplate debonded from the core.In the case when the core was glued to the faceplates,the face/core debonding was observed at 1/3 of the length away from the edge of the specimen.These phenomena were analyzed.Firstly,difference between the deflections of upper and lower faceplates was calculated by introducing the theory of beam on elastic foundation.Secondly,plastic analysis of the sandwich plates was carried out and cohesive strength analysis was utilized to evaluate the critical state of crack propagation.Finally,the critical interface crack lengths were obtained for different core types,and the relationship between critical crack length and cohesive stress was addressed at different bending angles.The results have shown that the analysis based on interface cohesive strength can illustrate the characteristics of delayed interface debonding for the composite sandwich plate with viscoelastic core.