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31.
The torsional impact response of a penny-shaped crack in a nonhomogeneous strip is considered. The shear modulus is assumed to be functionally graded such that the mathematics is tractable. Laplace and Hankel transforms were used to reduce the problem to solving a Fredholm integral equation. The crack tip stress field is obtained by considering the asymptotic behavior of Bessel function. Explicit expressions of both the dynamic stress intensity factor and the energy density factor were derived. And it is shown that, as crack driving force, they are equivalent for the present crack problem. Investigated are the effects of material nonhomogeneity and strip‘s highness on the dynamic fracture behavior.Numerical results reveal that the peak of the dynamic stress intensity factor can be suppressed by increasing the nonhomogeneity parameter of the shear modulus, and that the dynamic behavior varies little with the adjusting of the strip‘ s highness. 相似文献
32.
IntroductionAmongdifferenteigenvalueproblemsthereexistgaugetransformationswhichcanbeappliedtostudytheinfinite_dimensionalintegrableconstrainedflowproducedbyusingthecertainconstraintsonassociatedeigenvalueproblems[1,2 ] .Morerecently ,integrablefinite_dimensionalsystemsthatadmitaclassicalr_matrixdependingonthespectralproblemshavebeenstudiedextensively[3 ,4] .Buttherearemanyapplicationsofgaugetransformationswhichhavenotbeenstudiedyet.Themainaimofthepresentpaperistointroducesomenewapplicationsoft… 相似文献
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I.IntroductionDuetotheirintrinsiccouplingeffectbetweenmechanicalandelectricalfields,piezoelectricmaterialshavebeenwidelyusedintechnologyastransducersandsensorsand,morerecently,asactuatorsinsmartstructures.lnordertooptimizetheirmicrostructuresandunderstand… 相似文献
34.
本文通过测量伏安特性和光谱响应研究了被还原的n型NiNb2O6半导体单晶电极的光电化学性质及其能级结构,观察到两个吸收带,强者在3.24eV,对应于氧-锯跃迁;弱者在1.75eV,在可见光区,对应于镍-铌跃迁。探讨了阳极暗腐蚀、光腐蚀和水的光电解机理,绘出了NiNb2O6的电子能级图和主要的裂解能级。 相似文献
35.
CHENQINGHUI ZHANGBAOCAI 《高校应用数学学报(英文版)》1997,12(1):61-66
In this paper, the new coupled MKdV hierarchy and their Lsx pairs are oinained,Through introducing a suitable complex form of symplectic structure [5,8], a new integraHe sys-tem of the complex form in the Liouville sense is generated. Moreover, the representations of the solution for the coupled MKdV hierarchy are given by the invohifive solutions of the commutable . 相似文献
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In this paper, we investigate a low dimensional model of percussive drilling with vibro-impact to mimic the nonlinear dynamics of the bounded progression. Non- holonomity which arises in the stick-slip caused by the impact during drilling fails to be correctly identified via the classical techniques. A reduced model without non-holono- mity is derived by the introduction of a new state variable, of which averaging technique is employed successfully to detect the periodic motions. Local bifurcations are presented directly by using C-L method. Numerical simulations and the penetrating rate analysis along different choices of parame- ters have been carried out to probe the nonlinear behaviour and the optimal penetrating rate of the drilling system. 相似文献
40.
Let RP(k) denote the k-dimensional real projective space. This article determines which cobordism classes are represented by the total space of a fibering with prescribed base space RP(3)× RP(1), RP(2) × RP(1), RP(2)× RP(1)× RP(1) or RP(3)× RP(2). 相似文献