Abstract
Aerogels are low-density, highly nano-porous materials. Their engineering applications are limited due to their brittleness and hydrophilicity. Recently, a strong lightweight crosslinked silica aerogel has been developed by encapsulating the skeletal framework of amine-modified silica aerogels with polyureas derived by isocyanate. The mesoporous structure of the underlying silica framework is preserved through conformal polymer coating, and the thermal conductivity remains low. Characterization has been conducted on the thermal, physical properties and the mechanical properties under quasi-static loading conditions. In this paper, we present results on the dynamic compressive behavior of the crosslinked silica aerogel (CSA) using a split Hopkinson pressure bar (SHPB). A new tubing pulse shaper was employed to help reach the dynamic stress equilibrium and constant strain rate. The stress-strain relationship was determined at high strain rates within 114–4386 s−1. The effects of strain rate, density, specimen thickness and water absorption on the dynamic behavior of the CSA were investigated through a series of dynamic experiments. The Young’s moduli (or 0.2% offset compressive yield strengths) at a strain rate ∼350 s−1 were determined as 10.96/2.08, 159.5/6.75, 192.2/7.68, 304.6/11.46, 407.0/20.91 and 640.5/30.47 MPa for CSA with densities 0.205, 0.454, 0.492, 0.551, 0.628 and 0.731 g cm−3, respectively. The deformation and failure behaviors of a native silica aerogel with density (0.472 g cm−3), approximately the same as a typical CSA sample were observed with a high speed digital camera. Digital image correlation technique was used to determine the surface strains through a series of images acquired using high speed photography. The relative uniform axial deformation indicated that localized compaction did not occur at a compressive strain level of ∼17%, suggesting most likely failure mechanism at high strain rate to be different from that under quasi-static loading condition. The Poisson’s ratio was determined to be 0.162 in nonlinear regime under high strain rates. CSA samples failed generally by splitting, but were much more ductile than native silica aerogels.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.References
Barthelat, F., Wu, Z., Prorok, B.C., Espinosa, H.D.: Dynamic torsion testing of nanocrystalline coating using high speed photography and digital image correlation. Exp. Mech. 43(3), 331–340 (2003)
Bertino, M.F., Hund, J.F., Zhang, G., Sotiriou-Leventis, C., Tokuhiro, A.T., Leventis, N.: Room temperature synthesis of noble metal clusters in the mesopores of mechanically strong silica-polymer aerogel composites. J. Sol.-Gel. Sci. Technol. 30(1), 43–48 (2004)
Bruck, H.A., McNeill, S.R., Sutton, M.A., Peters, W.H.: Digital image correlation using Newton-Raphson method of partial differental correction. Exp. Mech. 29(3), 261–267 (1989)
Chen, W., Zhou, B.: Constitutive behavior of Epon 828/T-403 at various strain rates. Mech. Time-Dep. Mater. 2(2), 103–111 (1998)
Chen, W., Zhang, B., Forrestal, M.J.: A split Hopkinson bar technique for low-impedance material. Exp. Mech. 39(2), 81–85 (1999)
Chen, W., Lu, F., Cheng, M.: Tension and compression testing of two polymers under quasi-static and dynamic loading. Polym. Test. 21(2), 113–121 (2002)
Chen, W., Luo, H.: Dynamic compressive testing of intact and damaged ceramics. Ceramic Eng. Sci. Proc. 24(3), 411–416 (2003)
Chen, W., Luo, H.: Dynamic compressive responses of intact and damaged ceramics from a single split Hopkinson pressure bar experiment. Exp. Mech. 44(2), 295–299 (2004)
Chu, T.C., Ranson, W.F., Sutton, M.A., Peters, W.H.: Applications of digital-image-correlation techniques to experimental mechanics. Exp. Mech. 25(2), 232–244 (1985)
Frew, D.J., Forrestal, M.J., Chen, W.: A split Hopkinson bar technique to determine compressive stress-strain data for rock materials. Exp. Mech. 41(1), 40–46 (2001)
Frew, D.J., Forrestal, M.J., and Chen, W.: Pulse-shaping techniques for testing brittle materials with a split Hopkinson pressure bar. Exp. Mech. 42(1), 93–106 (2002)
Frew, D.J., Forrestal, M.J., Chen, W.: Pulse shaping techniques for testing elastic-plastic material with a split Hopkinson pressure bar. Exp. Mech. 45(2), 186–195 (2005)
Fricke, J.: Aerogels-highly tenuous solids with fascinating properties. J. Non-Cryst. Solids 100, 69–173 (1988)
Gama, B.A., Lopatnikov, S.L., Gillespie, J.W.: Hopkinson bar experimental technique: A critical review. Appl. Mech. Rev. 57(4), 223–250 (2004)
Gibson, L.J.: Mechanical behavior of metallic foams. Annu. Rev. Mater. Sci. 30, 181–227 (2000)
Gray, G.T.: Classic split-Hopkinson pressure bar technique. Mech. Test. Eval. ASM Handbook 8, 462–476 (2000)
Katti, A., Shimpi, N., Roy, S., Lu, H., Fabrizio, E.F., Dass, A., Capadona, L.A., Leventis, N.: Chemical, physical, and mechanical characterization of isocyanate cross-linked amine-modified silica aerogels. Chem. Mater. 18(2), 285–296 (2006)
Knauss, W.G., Kenner, V.H.: On the hygrothermomechanical characterization of polyvinylacetate. J. Appl. Phys. 51(10), 5131–5136 (1980)
Knauss, W.G., Zhu, W.: Nonlinearly viscoelastic behavior of polycarbonate. I. Response under pure shear. Mech. Time. dep. Mater. 6(3), 231–269 (2002)
Leventis, N., Sotiriou-Leventis, C., Zhang, G., Rawashdeh, A.M.: Nanoengineering strong silica aerogels. Nano Lett. 2(9), 957–960 (2002)
Leventis, N., Palczer, A., McCorkle, L., Zhang, G., Sotiriou-Leventis, C.: Nanoengineered silica polymer composite aerogels with no need for supercritical fluid drying. J. Sol. Gel. Sci. Technol. 35(2), 99–105 (2005)
Lu, H., Vendroux, G., Knauss, W.G.: Surface deformation measurements of a cylindrical specimen by digital image correlation. Exp. Mech. 37(4), 433–439 (2000)
Lu, H., Cary, P.D.: Deformation measurements by digital image correlation: Implementation of a second-order displacement gradient. Exp. Mech. 40(4), 393–400 (2000)
Luo, H., Chen, W.: Dynamic compressive response of intact and damaged AD995 alumina. Int. J. Appl. Ceramic Technol. 1(3), 254–260 (2004)
Meador, M.A.B., Fabrizio, E.F., Ilhan, F., Dass, A., Zhang, G., Vassilaras, P., Johnston, J.C., Leventis, N.: Cross-linking amine-modified silica aerogels with epoxies: Mechanical strong lightweight porous materials. Chem. Mater. 17(5), 1085–1098 (2005)
Miner, M.R., Hosticka, B., and Norris, P.M.: The effects of ambient humidity on the mechanical properties and surface chemistry of hygroscopic silica aerogel. J. Non-Cryst. Solids 350, 285–289 (2004)
Ravichandran, G., Subhash, G.: Critical appraisal of limiting strain rates for compression testing of ceramics in a split Hopkinson pressure bar. J. Am. Ceramic Soc. 77(1), 263–267 (1994)
Pierre, A.C., Pajonk, G.M.: Chemistry of aerogels and their applications. Chem. Rev. 102(11), 4243–4265 (2002)
Peters, W.H., Ranson, W.F.: Digital imaging techniques in experimental stress analysis. Opt. Eng. 21(3), 427–432 (1982)
Song, B., Chen, W.: Dynamic stress equilibration in split Hopkinson pressure bar tests on soft materials. Exp. Mech. 44(3), 300–312 (2004)
Song, B., Chen, W., Dou, S., Winfree, N., Kang, J.H.: Strain-rate effects on elastic and early cell-collapse response of a polystyrene foam. Int. J. Impact Eng. 31(5), 509–521 (2005)
Sutton, M.A., Wolters, W.J., Ranson, W.F., McNeil, S.R.: Determination of displacements using an improved digital image correlation method. Image Vision Comput. 1(3), 133–139 (1983)
Sutton, M.A., Cheng, M., Peters, W.H., Chao, Y.J., McNeill, S.R.: Application of an optimized digital correlation method to planar deformation analysis. Image Vis. Comput. 4(3), 143–150 (1986)
Thayer, A.M., Houston, C.E.: Large chemical and materials companies target small nanotechnology firms for venture investing, collaborations, and product innovations. in “Nanomaterials” Cover Story in Chemical and Engineering News 81(35), Sept.1, 2003, pp15–22
Woignier, T., Reynes, J., Alaoui, A.H. et al.: Different kinds of structure in aerogels: relationships with the mechanical properties. J. Non-Cryst. Solids 241(1), 45–52 (1998)
Woignier, T., Phalippou, J.: Mechanical Strength of silica aerogels. J. Non-Cryst. Solids 100, 404–408 (1988)
Vendroux, G., Knauss, W.G.: Submicron deformation field measurements: Part 2. Improved digital image correlation. Exp. Mech. 38(2), 86–92 (1998)
Yang, L.M., Shim, V.P.W.: An analysis of stress uniformity in split Hopkinson bar test specimens. Int. J. Impact Eng. 31(2), 129–150 (2005)
Zhang, G., Dass, A., Rawashdeh, A.M., Thomas, J., Counsil, J.A., Sotiriou-Leventis, C., Fabrizio, E.F., Ilhan, F., Vassilaras, P., Scheiman, D.A., McCorkle, L., Palczer, A., Johnston, J.C., Meador, M.A., Leventis, N.: Isocyanate-crosslinked silica aerogel monoliths: Preparation and characterization. J. Non-Cryst. Solids 350, 152–164 (2004)
Zhao, H., Gary, G.: A new method for the separation of waves: Application to the SHPB Technique for an unlimited duration of measurements. J. Mech. Phys. Solids 45(7), 1185–1202 (1997)
Author information
Authors and Affiliations
Corresponding authors
Rights and permissions
About this article
Cite this article
Luo, H., Lu, H. & Leventis, N. The compressive behavior of isocyanate-crosslinked silica aerogel at high strain rates. Mech Time-Depend Mater 10, 83–111 (2006). https://doi.org/10.1007/s11043-006-9015-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11043-006-9015-0