Compression Responses of Bio-Cellular Luffa Sponges

• Main Authors: Xiyue An, Qianqian Sui, Fangfang Sun, Zhiyuan Ma, Shu Jiang, Bing Ji, Hualin Fan
• Format: Article
• Language: English
• Published: North Carolina State University 2015-10-01
• Series: BioResources
• Subjects: Natural cellular luffa sponge; Mechanical properties; Mechanical testing; Hierarchical structure
• Online Access: http://ojs.cnr.ncsu.edu/index.php/BioRes/article/view/BioRes_10_4_8426_An_Compression_Responses_Biocellular_Luffa

Crushing behaviors of luffa sponges were studied through mechanical experiments. Controlled by four-order hierarchical and anisotropic structures, luffa sponges exhibit anisotropic responses along axial, radial, and circumferential directions. The ultra-thin but stiff inner surface layer dominates the crushing behavior, endowing the axially compressed luffa cylinder with structural integrity, enhancing the elastic deformation and yielding strength. In radial, circumferential, and lateral compressions, after removing the inner surface layer, luffa sponges are compliant and have large quasi-linear deformation before densification, without a plateau characterized by yielding and deformation. Immersed into water, crushed luffa sponge cylinders recover their geometry completely. However, compression strength is only partially restored. Gradual damage of the inner surface layer in water immersing/drying cycles greatly weakens the compression strength. In the case of removal of the inner surface layer, crushed luffa sponge cylinders completely restore their quasi-linear deformation ability during the water immersing/drying cycles.