This book is the third in a series of volumes by Y. C. Fung on biomechanics. The first two were Biomechanics: Mechanical Properties of Living Tissues (1981) and Biodynamics: Circulation (1984). In these books the author describes the constitutive behavior of biological tissues, the functional mechanics of the body's organs, and related engineering problems. The present volume, like the previous two, summarizes the application of an enormously wide spectrum of mechanics and thermodynamics to physiology and the engineering of biologically related problems. The mechanics applied includes rigid-body mechanics, mechanical vibration theory, viscous and perfect fluid theory, linear and nonlinear elasticity, wave propagation in fluid and solid media, multiphase mixture theory, chemical thermodynamics, and numerous subtopics of mechanics. The problems addressed cover the spectrum from birds flying and fish swimming to oxygen transport, human impact tolerance, and the engineering of activities at the cellular level. The introductory chapter describes the principles of mechanics, the modeling of phenomena, and the nature of the practical problems to be dealt with, e.g., basic physiology, prostheses, sports techniques, etc. Chapter 2 discusses the mechanics and modeling of whole bodies or whole body segments. Chapter 3 reviews the mechanics of the fluid dynamic forces that act on bodies moving through the fluid and Chapter 4 applies these results of classical mechanics to the mechanics of flying and swimming. The flight of birds and insects is compared with the flight of aircraft. The mechanics of hovering as well as the swimming of very small flagella are described. The circulatory system is considered in Chapters 5 and 6. Chapter 5 describes blood flow in the heart, lung, arteries, and veins while Chapter 6 addresses the microcirculation, blood rheology and blood flow in the lung. Respiratory gas flow, convection, diffusion, gas exchange, and pulmonary function tests are the topics of Chapter 7. Chapters 8 and 9 concern molecular diffusion and mass transport, fluid movement in interstitial space and across capillary blood vessel walls, filtration and transport across cell membranes. Chapter 10 is a presentation of nonlinear elasticity including the first report I have seen of an additive decomposition of the deformation gradient into a symmetric and an orthogonal matrix of tensor components. This additive decomposition is an analog of the multiplicative polar decomposition theorem used in continuum mechanics to separate the rotational and deformational components of a motion. Chapter 11 concerns residual strains in 'Professor, City College, New York, NY 10024.

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The previously developed microprestress-solidification theory for concrete creep and shrinkage is generalized for the effect of temperature ͑not exceeding 100°C͒. The solidification model separates the viscoelasticity of the solid constituent, the cement gel, from the chemical aging of material caused by solidification of cement and characterized by the growth of volume fraction of hydration products. This permits considering the viscoelastic constituent as non-aging. The temperature dependence of the rates of creep and of volume growth is characterized by two transformed time variables based on the activation energies of hydration and creep. The concept of microprestress achieves a grand unification of theory in which the long-term aging and all transient hygrothermal effects simply become different consequences of one and the same physical phenomenon. The microprestress, which is independent of the applied load, is initially produced by incompatible volume changes in the microstructure during hydration, and later builds up when changes of moisture content and temperature create a thermodynamic imbalance between the chemical potentials of vapor and adsorbed water in the nanopores of cement gel. As recently shown, this simultaneously captures two basic effects: First, the creep decreases with increasing age at loading after the growth of the volume fraction of hydrated cement has ceased; and, second, the drying creep, i.e., the transient creep increases due to drying ͑Pickett effect͒ which overpowers the effect of steady-state moisture content ͑i.e., less moisture-less creep͒. Now it is demonstrated that the microprestress buildup and relaxation also captures a third effect: The transitional thermal creep, i.e., the transient creep increase due to temperature change. For computations, an efficient ͑exponential-type͒ integration algorithm is developed. Finite element simulations, in which the apparent creep due to microcracking is taken into account separately, are used to identify the constitutive parameters and a satisfactory agreement with typical test data is achieved.