The delamination phenomenon in sandwich panels occurs in the form of face/core debonding. The grooved foams are usually employed in curved sandwich structures for easier formability and better adhesion. In this research, the debonding toughness of facesheet to the core in a sandwich beam with grooved core is investigated using numerical and experimental methods. The sandwich beam consisted of two Kevlar 49/polyester facesheets and a polyurethane foam core. To obtain the values of strain energy release rate, the Cracked Sandwich Beam (CSB) specimen along with the Modified Beam Theory (MBT) method was used for the data reduction of the test results. In the numerical part, a model based on the cohesive zone theory was employed to simulate the crack growth in the specimens. Comparison of the numerical and experimental load–displacement curves indicated that the proposed model can reasonably predict the behavior of the structure under similar loading conditions. The effect of foam-related parameters such as the number and width of core grooves on crack growth resistance was examined numerically. The results showed that increasing the number and width of the grooves enhanced the resistance of the sandwich beams against the growth of interfacial cracks.

中文翻译：

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带槽芯夹芯板的断裂韧性和抗裂纹扩展性

夹芯板中的分层现象以面/芯剥离的形式发生。带凹槽的泡沫通常用于弯曲的夹层结构，以便更容易成型和更好的附着力。在这项研究中，使用数值和实验方法研究了带槽芯的夹层梁中面板与芯的剥离韧性。夹层梁由两个 Kevlar 49/聚酯面板和一个聚氨酯泡沫芯组成。为了获得应变能释放率的值，裂纹夹心梁 (CSB) 试样与修正梁理论 (MBT) 方法一起用于测试结果的数据缩减。在数值部分，采用基于内聚区理论的模型来模拟试样中的裂纹扩展。数值和实验载荷-位移曲线的比较表明，所提出的模型可以合理地预测结构在类似载荷条件下的行为。对泡沫相关参数（例如芯槽的数量和宽度）对裂纹扩展阻力的影响进行了数值研究。结果表明，增加凹槽的数量和宽度可以增强夹层梁对界面裂纹扩展的抵抗力。