Hysteresivity
Hysteresivity derives from “hysteresis”, meaning “lag”. It is the tendency to react slowly to an outside force, or to not return completely to its original state. Whereas the area within a hysteresis loop represents energy dissipated to heat and is an extensive quantity with units of energy, the hysteresivity represents the fraction of the elastic energy that is lost to heat, and is an intensive property that is dimensionless.
Overview
[edit]When a force deforms a material it generates elastic stresses and internal frictional stresses. Most often, frictional stress is described as being analogous to the stress that results from the flow of a viscous fluid, but in many engineering materials, in soft biological tissues, and in living cells, the concept that friction arises only from a viscous stress is now known to be erroneous.[1][2] For example, Bayliss and Robertson [3] and Hildebrandt [4] demonstrated that frictional stress in lung tissue is dependent upon the amount of lung expansion but not the rate of expansion, findings that are fundamentally incompatible with the notion of friction being caused by a viscous stress. If not by a viscous stress, how then does friction arise, and how is it properly described?
In many inert and living materials, the relationship between elastic and frictional stresses turns out to be very nearly invariant (something unaltered by a transformation). In lung tissues, for example, the frictional stress is almost invariably between 0.1 and 0.2 of the elastic stress, where this fraction is called the hysteresivity, h, or, equivalently, the structural damping coefficient.[2] It is a simple phenomenological fact, therefore, that for each unit of peak elastic strain energy that is stored during a cyclic deformation, 10 to 20% of that elastic energy is taxed as friction and lost irreversibly to heat. This fixed relationship holds at the level of the whole lung[5] ,[6][7] isolated lung parenchymal tissue strips,[8] isolated smooth muscle strips,[2][9] and even isolated living cells.[10][11][12][13]
This close relationship between frictional and elastic stresses is called the structural damping law[1][2][4][14] or, sometimes, the constant phase model.[5] The structural damping law implies that frictional losses are coupled tightly to elastic stresses rather than to viscous stresses, but the precise molecular mechanical origin of this phenomenon remains unknown.[10][15] ' In material science, the complex elastic modulus of a material, G*(f'), at frequency of oscillatory deformation f, is given by,
where:
- G*(f)= complex elastic modulus at frequency of oscillatory deformation, f
- G′ = the elastic modulus
- G′′ = the loss modulus
- j 2 = −1
This relationship can be rewritten as,
where:
- h = G′′/G′.
In systems conforming to the structural damping law, the hysteresivity h is constant with or insensitive to changes in oscillatory frequency, and the loss modulus G′′ (= hG′) becomes a constant fraction of the elastic modulus.
See also
[edit]References
[edit]- ^ a b Crandall, S.H. (1970). "The role of damping in vibration theory". Journal of Sound and Vibration. 11 (1). Elsevier BV: 3–18. Bibcode:1970JSV....11....3C. doi:10.1016/s0022-460x(70)80105-5. ISSN 0022-460X.
- ^ a b c d Fredberg, J. J.; Stamenovic, D. (1989-12-01). "On the imperfect elasticity of lung tissue". Journal of Applied Physiology. 67 (6). American Physiological Society: 2408–2419. doi:10.1152/jappl.1989.67.6.2408. ISSN 8750-7587. PMID 2606848.
- ^ Bayliss, L. E.; Robertson, G. W. (1939-03-22). "The visco-elastic properties of the lungs". Quarterly Journal of Experimental Physiology and Cognate Medical Sciences. 29 (1). Wiley: 27–47. doi:10.1113/expphysiol.1939.sp000792. ISSN 0033-5541.
- ^ a b Hildebrandt, J. (1969). "Comparison of mathematical models for cat lung and viscoelastic balloon derived by laplace transform methods from pressure-volume data". The Bulletin of Mathematical Biophysics. 31 (4). Springer Science and Business Media LLC: 651–667. doi:10.1007/bf02477779. ISSN 0007-4985. PMID 5360349.
- ^ a b Hantos, Z.; Daroczy, B.; Suki, B.; Nagy, S.; Fredberg, J. J. (1992-01-01). "Input impedance and peripheral inhomogeneity of dog lungs". Journal of Applied Physiology. 72 (1). American Physiological Society: 168–178. doi:10.1152/jappl.1992.72.1.168. ISSN 8750-7587. PMID 1537711.
- ^ Jensen, Andrew; Atileh, Haytham; Suki, Bela; Ingenito, Edward P.; Lutchen, Kenneth R. (2001-07-01). "Selected Contribution: Airway caliber in healthy and asthmatic subjects: effects of bronchial challenge and deep inspirations". Journal of Applied Physiology. 91 (1). American Physiological Society: 506–515. doi:10.1152/jappl.2001.91.1.506. ISSN 8750-7587. PMID 11408470. S2CID 12361807.
- ^ "commentary". Journal of Applied Physiology. 91 (1). American Physiological Society: 504–505. 2001-07-01. doi:10.1152/jappl.2001.91.1.504. ISSN 8750-7587.
- ^ Fredberg, J. J.; Bunk, D.; Ingenito, E.; Shore, S. A. (1993-03-01). "Tissue resistance and the contractile state of lung parenchyma". Journal of Applied Physiology. 74 (3). American Physiological Society: 1387–1397. doi:10.1152/jappl.1993.74.3.1387. ISSN 8750-7587. PMID 8482682.
- ^ Fredberg, J. J.; Jones, K. A.; Nathan, M.; Raboudi, S.; Prakash, Y. S.; Shore, S. A.; Butler, J. P.; Sieck, G. C. (1996-12-01). "Friction in airway smooth muscle: mechanism, latch, and implications in asthma". Journal of Applied Physiology. 81 (6). American Physiological Society: 2703–2712. doi:10.1152/jappl.1996.81.6.2703. ISSN 8750-7587. PMID 9018525.
- ^ a b Bursac, Predrag; Lenormand, Guillaume; Fabry, Ben; Oliver, Madavi; Weitz, David A.; Viasnoff, Virgile; Butler, James P.; Fredberg, Jeffrey J. (2005-06-05). "Cytoskeletal remodelling and slow dynamics in the living cell". Nature Materials. 4 (7). Springer Science and Business Media LLC: 557–561. Bibcode:2005NatMa...4..557B. doi:10.1038/nmat1404. ISSN 1476-1122. PMID 15937489. S2CID 18895076.
- ^ Fabry, Ben; Maksym, Geoffrey N.; Butler, James P.; Glogauer, Michael; Navajas, Daniel; Fredberg, Jeffrey J. (2001-09-13). "Scaling the Microrheology of Living Cells". Physical Review Letters. 87 (14). American Physical Society (APS): 148102. Bibcode:2001PhRvL..87n8102F. doi:10.1103/physrevlett.87.148102. hdl:2445/12785. ISSN 0031-9007. PMID 11580676.
- ^ Fabry, Ben; Maksym, Geoffrey N.; Butler, James P.; Glogauer, Michael; Navajas, Daniel; Taback, Nathan A.; Millet, Emil J.; Fredberg, Jeffrey J. (2003-10-27). "Time scale and other invariants of integrative mechanical behavior in living cells". Physical Review E. 68 (4). American Physical Society (APS): 041914. Bibcode:2003PhRvE..68d1914F. doi:10.1103/physreve.68.041914. hdl:2445/18687. ISSN 1063-651X. PMID 14682980.
- ^ Fabry, Ben; Maksym, Geoffrey N.; Shore, Stephanie A.; Moore, Paul E.; Panettieri, Reynold A.; Butler, James P.; Fredberg, Jeffrey J. (2001-08-01). "Selected Contribution: Time course and heterogeneity of contractile responses in cultured human airway smooth muscle cells". Journal of Applied Physiology. 91 (2). American Physiological Society: 986–994. doi:10.1152/jappl.2001.91.2.986. ISSN 8750-7587. PMID 11457818. S2CID 39701905.
- ^ Fung Y. Biomechanics: Mechanical Properties of Living Tissues. New York:: Springer-Verlag, 1988.
- ^ Hubmayr, Rolf D. (2000-10-01). "Biology lessons from oscillatory cell mechanics". Journal of Applied Physiology. 89 (4). American Physiological Society: 1617–1618. doi:10.1152/jappl.2000.89.4.1617. ISSN 8750-7587. PMID 11007603.
Further reading
[edit]- Kaczka, David W.; Ingenito, Edward P.; Suki, Bela; Lutchen, Kenneth R. (1997-05-01). "Partitioning airway and lung tissue resistances in humans: effects of bronchoconstriction". Journal of Applied Physiology. 82 (5). American Physiological Society: 1531–1541. doi:10.1152/jappl.1997.82.5.1531. ISSN 8750-7587. PMID 9134903.