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In this research, linear and non-linear stability behaviour of a thin circular FGM plate subjected to the uniform temperature rise and the constant angular velocity loadings is analyzed. Properties of the FGM media are distributed across the thickness based on a power law form. Each property of the metal or ceramic constituents is considered to be the function of temperature based on the Touloukian model. General equilibrium equations for such conditions are obtained based on the classical plate theory. At first, the non-linear governing equations are established in a complete asymmetrical form. After that, two different analytical methods are presented to study the bifurcation behaviour. Existence of bifurcation phenomenon is examined. Pre-buckling analysis is performed for a plate with the immovable clamped edge. Stability equations are obtained based on the adjacent equilibrium criterion. The resulted equations are solved via the two distinct methodologies, i.e. the exact solution in terms of Coulomb wave functions and the power series method. A non-linear solution is also presented to detect the equilibrium path of the heated rotating FGM plate. It is found that the angular speed may stabilize the homogeneous circular plate which buckles during uniform heating. Furthermore, snapping may occur for FGM plates under the simultaneous action of heating and uniform rotation. 相似文献
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Mohammad Khajehzadeh Mohd Raihan Taha Ahmed El-Shafie Mahdiyeh Eslami 《浙江大学学报(A卷英文版)》2011,12(6):415-427
This paper deals with the economically optimized design and sensitivity of two of the most widely used systems in geotechnical
engineering: spread footing and retaining wall. Several recent advanced optimization methods have been developed, but very
few of these methods have been applied to geotechnical problems. The current research develops a modified particle swarm optimization
(MPSO) approach to obtain the optimum design of spread footing and retaining wall. The algorithm handles the problem-specific
constraints using a penalty function approach. The optimization procedure controls all geotechnical and structural design
constraints while reducing the overall cost of the structures. To verify the effectiveness and robustness of the proposed
algorithm, three case studies of spread footing and retaining wall are illustrated. Comparison of the results of the present
method, standard PSO, and other selected methods employed in previous studies shows the reliability and accuracy of the algorithm.
Moreover, the parametric performance is investigated in order to examine the effect of relevant variables on the optimum design
of the footing and the retaining structure utilizing the proposed method. 相似文献
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Recent second/foreign language (L2) research has witnessed the application of sociocultural tenets to L2 classrooms. This study aimed to probe whether Iranian L2 learners’ engagement in ZPD-activated collaborative dialogue, or ‘languaging’, mediates their learning process and, specifically, their appropriate use of metadiscourse to address content, organisation and audience issues in writing. English-as-a-foreign-language-writing classes at two universities were assigned to four different instructional conditions, namely, ZPD-activated collaborative, ZPD-free collaborative, fine-tuned L2-input provision and prevalent teacher-fronted approaches. The data comprised metadiscourse-oriented writing test scores, weekly writings and audio-recorded in-class collaborative dialogues of the ZPD groups. The results demonstrated the ZPD-activated collaborative writing approach significantly facilitated the learners’ appropriate use of metadiscourse. Complementary interpretative analysis of the ZPD participants’ metadiscourse-related episodes showed that the initially-other-regulated (undistributed) writing tasks became progressively reciprocal with less-skilled peers displaying microgenetic use of L2 metadiscourse resources and dynamically assuming more participatory roles in regulating the writing tasks. The findings suggest engagement in ZPD-activated ‘languaging’ is crucial to shaping opportunities for L2 learners’ microgenetic learning and to their longer term cognitive development. In sum, the application of sociocultural tenets and notions has shown to be highly fruitful in explaining the social genesis of L2 development as a higher order psychological functioning. 相似文献
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ＩＮＴＲＯＤＵＣＴＩＯＮＷｅｗｉｌｌｆｉｒｓｔｒｅｃａｌｌｓｏｍｅａｌｇｅｂｒａｉｃｄｅｆｉｎｉｔｉｏｎｓｔｈａｔｗｉｌｌｂｅｕｓｅｄｉｎｔｈｅｐａｐｅｒ.ＡｈｙｐｅｒｓｔｒｕｃｔｕｒｅｉｓａｓｅｔＨｔｏｇｅｔｈｅｒｗｉｔｈａｆｕｎｃｔｉｏｎ·∶Ｈ×Ｈ→Ｐ 相似文献
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Mohsen Damavandi Mansour Eslami David J. Pearsall 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(1):1-12
Running on side-sloped surfaces is a common obstacle in the environment; however, how and to what extent the lower extremity kinematics adapt is not well known. The purpose of this study was to determine the effects of side-sloped surfaces on three-dimensional kinematics of hip, knee, and ankle during stance phase of running. Ten healthy adult males ran barefoot along an inclinable runway in level (0°) and side-sloped (10° up-slope and down-slope inclinations, respectively) configurations. Right hip, knee, and ankle angles along with their time of occurrence were analysed using repeated measures MANOVA. Up-slope hip was more adducted (p = 0.015) and internally rotated (p = 0.030). Knee had greater external rotations during side-sloped running at heel-strike (p = 0.005), while at toe-off, it rotated externally and internally during up-slope and down-slope running, respectively (p = 0.001). Down-slope ankle had greatest plantar flexion (p = 0.001). Up-slope ankle had greatest eversion compared with down-slope (p = 0.043), while it was more externally rotated (p = 0.030). These motion patterns are necessary to adjust the lower extremity length during side-sloped running. Timing differences in the kinematic events of hip adduction and external rotation, and ankle eversion were observed (p = 0.006). Knowledge on these alterations is a valuable tool in adopting strategies to enhance performance while preventing injury. 相似文献
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