开孔泡沫铜的压-压疲劳行为

Compression-Compression Fatigue Behavior of Open-Cell Foam Copper

对具有相同孔径的开孔泡沫铜进行单轴准静态压缩和压-压疲劳试验,分析开孔泡沫铜的压缩特性和疲劳行为,并讨论了疲劳失效方式及破坏机理。结果表明:开孔泡沫铜的压缩应力-应变曲线由弹性变形阶段、平台应力阶段、密实阶段3个阶段组成;在压-压疲劳过程中开孔泡沫铜主要经历了疲劳损伤积累区、应变激增区和持续破坏区3个阶段,应力水平越低开孔泡沫铜的寿命越长;在剪切力作用下,开孔泡沫铜中间部位形成一条与水平方向存在一定角度的挤压带,随着累积应变的增加,挤压带中孔洞结构持续破坏而形成一条几乎水平的压溃带;开孔泡沫铜的疲劳失效机理为孔棱表皮脱落、颈缩、断裂以及棱柱结的开裂。

Uniaxial quasi-static compression and compression-compression fatigue tests were performed on open-cell foam copper with the same pore size. The compression characteristics and fatigue behavior of open-cell foam copper were analyzed, and the fatigue failure mode and failure mechanism were discussed. The results show that the compressive stress-strain curve of open-cell foam copper consisted of elastic deformation stage, platform stress stage, and compaction stage. During compression-compression fatigue process, the open-cell foam copper mainly experienced fatigue damage accumulation zone, strain surge zone, and continuous failure zone. The lower the stress level, the longer the life of open-cell foam copper. Under the action of shearing force, the middle part of the open-cell foam copper formed an extruded zone with a certain angle to the horizontal direction. As the accumulated strain increasing, the pore structure in the extruded zone continued to be destroyed and formed an almost horizontal crush zone. The fatigue failure mechanism of open-cell foam copper was the peeling, necking, fracture of pore edges, and cracking of pore junction.