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AbstractBiological structures integrate morphometry (shape-based rules) with materials design to maximize organism survival. The exoskeleton of the armored fish,Polypterus senegalus, balances flexibility with protection from predatory and territorial threats. Material properties of the exoskeleton are known; however, the geometric design rules underlying its anisotropic flexibility are uncharacterized. Here, we show how scale shape, articulation, and composite architecture produce anisotropic mechanics using bio-inspired, multi-material 3D-printed prototypes. Passive loading (draping) shows that compliant connections between the scales contribute to mechanical anisotropy. Simulated and experimental active loading (bending) show orientation-dependent stiffness ranging over orders of magnitude, including ‘mechanical invisibility’ of the scales where they do not add stiffness to the exoskeleton. The results illustrate how morphometry provides a powerful tool to tune flexibility in composite architectures independent of varying constituent materials composition. We anticipate that introducing morphometric design strategies will enable flexible, protective systems tuned to complex shapes and functions.

Low density composites of sodium montmorillonite and poly(amide-imide) polymers have been created using an ice templating method, which serves as an alternative to the often-difficult foaming of high temperature/high performance polymers. The starting polymer was received in the poly(amic acid) form which can be cured using heat, into a water insoluble amide-imide copolymer. The resulting materials have densities in the 0.05 g/cm3 range and have excellent mechanical properties. Using a tertiary amine as a processing aid provides for lower viscosity and allows more concentrated polymer solutions to be used. The concentration of the amine relative to the acid groups on the polymer backbone has been found to cause significant difference in the mechanical properties of the dried materials. The synthesis and characterization of low density versions of two poly(amide-imide) polymers and their composites with sodium montmorillonite clay are discussed in the present work, Postprint (published version)

Contains experimental data for the paper "Mechanistic Origins of Bombardier Beetle (Brachinini) Explosion-Induced Defensive Spray Pulsation," by Eric M. Arndt, Wendy Moore, Wah-Keat Lee, and Christine Ortiz, which was accepted by Science on March 16, 2015, and which is in press. Data sets are organized by beetle, with beetle numbers corresponding to those listed in Tables S1 and S2 of the paper supplement. Images stacks are ZIP-compressed. The total size of all files (compressed) is 62.9 GB. For Beetles 6-14, the raw and processed 2000-fps x-ray videos are provided as TIFF image stacks. AVI videos (25-fps playback) of all recorded sprays as well as the Matlab processing scripts for each data set (file paths redacted) are also provided. CCTV video was not recorded. The Excel spreadsheet Data_summary.xlsx is a catalog of the data and provides x-ray and (where available) CCTV frame numbers for all sprays. The citable handle for this collection is hdl.handle.net/1721.1/96123., Use of the Advanced Photon Source was supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. This work was supported in part by the U. S. Army Research Laboratory and the U. S. Army Research Office through the MIT Institute of Soldier Nanotechnologies under Contract No. W911NF-13-D-0001 and in part by the National Science Foundation through the MIT Center for Materials Science and Engineering under Contract No. DMR-08-19762. This research was funded in part by the U. S. Department of Defense, Office of the Director, Defense Research and Engineering, through the National Security Science and Engineering Faculty Fellowship awarded to C.O. under Contract No. N00244-09-1-0064; in part by the National Science Foundation through funding awarded to W.M. under Contract No. DEB-0908187; and in part by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-SC0012704. Experiment data are available for download from DSpace@MIT at: http://hdl.handle.net/1721.1/96123.

Contains experimental data for the paper "Mechanistic Origins of Bombardier Beetle (Brachinini) Explosion-Induced Defensive Spray Pulsation," by Eric M. Arndt, Wendy Moore, Wah-Keat Lee, and Christine Ortiz, which was accepted by Science on March 16, 2015, and which is in press. Data sets are organized by beetle, with beetle numbers corresponding to those listed in Tables S1 and S2 of the paper supplement. Images stacks are ZIP-compressed. The total size of all files (compressed) is 62.9 GB. For Beetles 2-4, the raw 250-fps x-ray and 30-fps CCTV videos are provided as TIFF image stacks. The Excel spreadsheet Data_summary.xlsx is a catalog of the data and provides x-ray and (where available) CCTV frame numbers for all sprays. The citable handle for this collection is hdl.handle.net/1721.1/96123., Use of the Advanced Photon Source was supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. This work was supported in part by the U. S. Army Research Laboratory and the U. S. Army Research Office through the MIT Institute of Soldier Nanotechnologies under Contract No. W911NF-13-D-0001 and in part by the National Science Foundation through the MIT Center for Materials Science and Engineering under Contract No. DMR-08-19762. This research was funded in part by the U. S. Department of Defense, Office of the Director, Defense Research and Engineering, through the National Security Science and Engineering Faculty Fellowship awarded to C.O. under Contract No. N00244-09-1-0064; in part by the National Science Foundation through funding awarded to W.M. under Contract No. DEB-0908187; and in part by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-SC0012704. Experiment data are available for download from DSpace@MIT at: http://hdl.handle.net/1721.1/96123.

Contains experimental data for the paper "Mechanistic Origins of Bombardier Beetle (Brachinini) Explosion-Induced Defensive Spray Pulsation," by Eric M. Arndt, Wendy Moore, Wah-Keat Lee, and Christine Ortiz, which was accepted by Science on March 16, 2015, and which is in press. Data sets are organized by beetle, with beetle numbers corresponding to those listed in Tables S1 and S2 of the paper supplement. Images stacks are ZIP-compressed. The total size of all files (compressed) is 62.9 GB. For Beetle 5, the raw and processed 1000-fps x-ray videos are provided as TIFF image stacks. An AVI video (25-fps playback) of the recorded spray as well as the Matlab processing script (file path redacted) are also provided. CCTV video was not recorded. The Excel spreadsheet Data_summary.xlsx is a catalog of the data and provides x-ray and (where available) CCTV frame numbers for all sprays. The citable handle for this collection is hdl.handle.net/1721.1/96123., Use of the Advanced Photon Source was supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. This work was supported in part by the U. S. Army Research Laboratory and the U. S. Army Research Office through the MIT Institute of Soldier Nanotechnologies under Contract No. W911NF-13-D-0001 and in part by the National Science Foundation through the MIT Center for Materials Science and Engineering under Contract No. DMR-08-19762. This research was funded in part by the U. S. Department of Defense, Office of the Director, Defense Research and Engineering, through the National Security Science and Engineering Faculty Fellowship awarded to C.O. under Contract No. N00244-09-1-0064; in part by the National Science Foundation through funding awarded to W.M. under Contract No. DEB-0908187; and in part by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-SC0012704. Experiment data are available for download from DSpace@MIT at: http://hdl.handle.net/1721.1/96123.