有/无填充介质对裂纹动态断裂特性影响的实验研究

Experimental Study on the Effect of the Presence or Absence of Filled Media on Dynamic Fracture Characteristics of Cracks

为了研究有/无填充介质对裂纹动态断裂特性的影响,利用动态焦散线实验方法结合高速相机对含预制缺陷的试件进行了三点弯冲击断裂实验。研究结果表明:冲击载荷作用下运动主裂纹与预制缺陷贯通后,预制裂纹中有/无填充介质影响次生裂纹的起裂位置、数量、起裂模式、起裂所需时间。在预制裂纹中无填充介质的情况下,沿预制裂纹左右两侧对称产生2条次生裂纹,次生裂纹起裂时是Ⅰ+Ⅱ混合模式断裂;在填充环氧树脂介质情况下,沿预制裂纹中心处产生1条次生裂纹,次生裂纹起裂时是Ⅰ型断裂;同时无填充介质试件次生裂纹起裂所需时间大于填充了环氧树脂的试件。

In order to study the influence of the presence/absence of filled media on the dynamic fracture characteristics of the cracks,a three-point bending impact fracture experiment is performed on the specimens with prefabricated defects using a dynamic caustics experimental method combined with a high-speed camera.The results show that under the impact load,the presence/absence of the filled medium in the pre-crack affects the crack initiation position,number,crack initiation mode,and time required for crack initiation of the secondary crack after the movement of the main crack penetrates the prefabricated flaw.In the case of no pre-filled cracked media,two secondary cracks are generated symmetrically along the left and right sides of the pre-fabricated cracks.The secondary cracks are initiated by the I+II mixed-mode fractures.In the case of epoxy-filled media,one secondary crack occurs along the center of the prefabricated crack,which is a type I fracture when the secondary crack initiates.At the same time,the time required for the secondary crack initiation of the test specimen without filler media is greater than that of the specimen filled with epoxy resin.