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41.
It is shown that time-dependent temperatures in a transient, conductive system can be approximately modeled by a fractional-order
differential equation, the order of which depends on the Biot number. This approximation is particularly suitable for complex
shapes for which a first-principles approach is too difficult or computationally time-consuming. Analytical solutions of these
equations can be written in terms of the Mittag-Leffler function. The approximation is especially useful if a suitable fractional-order
controller is to be designed for the system. 相似文献
42.
This paper presents the applications of digital image correlation technique to the mesoscopic damage and fracture study of
some granular based composite materials including steelfiber reinforced concrete, sandstone and crystal-polymer composite.
The deformation fields of the composite materials resulted from stress localization were obtained by the correlation computation
of the surface images with loading steps and thus the related damage prediction and fracture parameters were evaluated. The
correlation searching could be performed either directly based on the gray levels of the digital images or from the wavelet
transform (WT) coefficients of the transform spectrum. The latter was developed by the authors and showed higher resolution
and sensitivity to the singularity detection. Because the displacement components came from the rough surfaces of the composite
materials without any coats of gratings or fringes of optical interferometry, both surface profiles and the deformation fields
of the composites were visualized which was helpful to compare each other to analyze the damage of those heterogeneous materials.
The project supported by the National Natural Science Foundation of China (10125211 and 10072002), the Scientific Committee
of Yunnan Province for the Program of Steel Fiber Reinforced Concrete, and the Institute of Chemical Materials, CAEP at Mianyang 相似文献
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I. M. Lavit Nguyen Viet Trung 《Journal of Applied Mechanics and Technical Physics》2008,49(3):491-499
The thermoelastoplastic fracture mechanics problem of a thick-walled cylinder subjected to internal pressure and a nonuniform
temperature field is solved by the method of elastic solutions combined with the finite-element method. The correctness of
the solution is provided by using the Barenblatt crack model, in which the stress and strain fields are regular. The elastoplastic
problem of a cracked cylinder subjected to internal pressure and a nonuniform temperature field are solved. The calculation
results are compared with available data.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 3, pp. 173–183, May–June, 2008. 相似文献