9R2. Physics of Strength and Fracture Control: Adaptation of Engineering Materials and Structures. - AA Komarovsky (Lab of Phys of Strength, Sci and Eng Center for Non-Traditional Technologies (SALUTA), Kiev, Ukraine). CRC Press LLC, Boca Raton FL. 2003. 639 pp. ISBN 0-8493-1151-9. $179.95.
Reviewed by HW Haslach Jr (Dept of Mech Eng, Univ of Maryland, College Park MD 20742-3035).
The safety of engineering structures depends on the designer’s ability to predict the resistance of solids to failure. The author believes that a new concept of the science of the resistance of materials is needed since existing techniques have been exhausted. In particular, because that author believes that all phenomena have an explanation, statistical methods of design are rejected. The focus of this book is on analysis of the interatomic bonds of a solid and their consequences for bulk behavior.
A good theory of the non-equilibrium thermodynamics of solids is needed to understand the response of solids to forces, heat, magnetism, and other fields. In this book, the model given closely parallels the classical analysis of fluids. The internal pressure or stress in the solid is defined as the vector representing the resistance to volume change, where F is the force of atomic interaction and is the surface areas enclosing a volume. The proposed thermodynamic equation of state is then where s is the entropy vector and is the magnitude of P. Apparent conflicts of vectors and scalars occur frequently in the equations of this book. The given derivation is quasi-static because it assumes that the body passes through a sequence of equilibrium states.
The state of the solid is defined to be the shape of the rotos resulting from the solidi-fication process. A rotos is a closed dynamic cell of solids. The equation of state relates the temperature of the solid structure to its ability to generate resistance forces. Compressions are those atoms located on the decreasing portion of a bond force minimum and provide resistance under heat adsorption, and dilatons are those located on the increasing portion to a force maximum and offer resistance in heat radiation. The compression-dilaton pattern of the bonds in a structure determines its response to loads, temperature, and other environmental conditions. Dilaton materials resist compression while compression materials resist tension. Chapter 3 provides experimental verification of this relation and its influence on the size effect, stresses, and aging in the response of solids, in particular that of concrete. The traditional design strategy of increasing the size of a structure to support loads increases the number of cracks and the possibility of crack growth.
The description of dynamic loading, durability, creep, and fatigue is developed from the equation of state to try to explain the physical nature of the time-dependent response. The increased resistance influences the initiation and propagation of cracks. Durability is related to entropy. The theory is claimed to be a generalization of the kinetic theory of strength which postulates that thermal fluctuations are key in breaking atomic bonds. In service, the equation of state describes how a structure is strongly influenced by environmental effects such as moisture, radiation, hydrogen embrittlement, and aging due to thermal and load fields.
Fracture is attributed to what is called the Maxwell-Boltzmann factor (from the distribution of energy states), which describes the concentration density and energy of particles in a given region of the solid and which introduces stress-concentrations. As in classical fracture mechanics, breaking of bonds releases internal energy. Fracture is a thermally dependent process. Deformation and fracture always occur together; fracture is not due, as postulated by others, to the breaking of the weakest link. Fatigue life is again related to thermodynamic parameters through the equation of state. Fatigue is due to phase transitions in the compression-dilaton bond pattern.
Two final chapters give applications to service life control and the theory of design. Methods of diagnosing the strength of the material described include thermography (emphasizing the thermal nature of internal stresses and strains), hardness, and durability analysis. The methods of adaptation of the materials to service conditions cover controlling the strength and fracture, heat treatment, use of compensating fields, and heterogeneity of the material. Physics of Strength and Fracture Control: Adaptation of Engineering Materials and Structures is a serious attempt to explain bulk structural behavior from the atomic structure. However, the confusion of vectors and scalars in the mathematical expressions for the equation of state often overshadows the physical insights presented. Specific detailed applications would have helped convince the reader that this design strategy can be carried out in practice.