Heterogeneous deformation

That this is not always the case should be expected. In fact, if it was not for heterogeneous localization of some flow phenomena, it would be very diflicult to initiate secondary explosives, or to effect shock-induced chemical reactions in solids. Heterogeneous shear deformation in metals has also been invoked as an explanation for a reduction in shear strength in shock compression as compared to quasi-isentropic loading. We present here a brief discussion of some aspects of heterogeneous deformation in shock-loaded solids. 

The evolution of T, is just an exercise in mesoscale thermodynamics [13]. These expressions, in combination with (7.54), incorporate concepts of heterogeneous deformation into a eonsistent mierostruetural model. Aspects of local material response under extremely rapid heating and cooling rates are still open to question. An important contribution to the micromechanical basis for heterogeneous deformation would certainly be to establish appropriate laws of flow-stress evolution due to rapid thermal cycling that would provide a physical basis for (7.54). 

Nevertheless, as response data have accumulated and the nature of the porous deformation problems has crystallized, it has become apparent that the study of such solids has forced overt attention to issues such as lack of thermodynamic equilibrium, heterogeneous deformation, anisotrophic deformation, and inhomogeneous composition—all processes that are present in micromechanical effects in solid density samples but are submerged due to continuum approaches to mechanical deformation models. 

Locally Heterogeneous Deformation Crazing and Slow Crack Growth. .. 22... 

It seems to be important to mention that the formation of defects necessarily leads to locally heterogeneous deformation, which is the subject of the following section. However, the creep deformation remains macroscopically homogeneous if such defects are numerous and spatially well distributed. 

It would be highly desirable to have other quantities simulated in this model, as they would allow a more thorough testing of the model through comparisons with the available experimental data (e.g., quantities such as adsorption isotherms at several temperatures, or the coverage dependence of the isosteric heat of adsorption). These simulated data are not presently available because the heterogeneous deformable bundle model is very recent. 

The crystalline lamellar organization of PP was clearly observed in the PP dominant matrix of the undrawn TPV. The TEM images of the drawn TPV sample indicated that the dispersed EPDM domains (dark portion in the image) are highly elongated along the extension direction, and the drawn process promotes a rather heterogeneous deformation in the matrix (Fig. 8.15). It should be noted here that the PP dominant matrix and the dispersed EPDM domains were completely bonded, and the interfacial separation between the matrix and the EPDM domains was not observed in the drawn TPV samples. 

The stress-strain curves simulate a homogeneous deformation process of the polymer. However, on the microscale above the linear part of the stress-strain curve (see Fig. 1.15, curves (b), (c), (d)), localized heterogeneous deformation mechanisms occur. Depending on the polymer chemical structure and entanglement molecular weight Mg and on the deformation conditions (temperature and strain rate), several types of heterogeneous deformation are observed micro plastic zones, crazes, deformation zones, and shear bands. Their main features are sketched in Fig. 1.18. 

Jones PT, Van Gerven T, Van Ackert K, Geysen D, Binnemans K, Fransaer J, Blanpain B, Mishra B, Apelian D (2011) Characterization and modeling of heterogeneous deformation in commercial purity titanium. JOM 63 66-73... 

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