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与两相材料界面接触的裂纹对SH波的散射 总被引:1,自引:0,他引:1
利用积分变换方法得出了两相材料中作用简谐集中力时的格林函数.根据所得的格林函数并利用Betti-Rayleigh互易定理得出了与界面接触裂纹的散射波场.裂纹的散射波场可分解为两部分,一部分为奇异的散射场,另一部分为有界的散射场.利用分解后的散射场,可得裂纹在SH波作用下的超奇异积分方程.根据裂纹散射场的奇异部分和Cauchy型奇异积分的性质得出了裂纹和界面接触点处的奇性应力指数和接触点角形域内的奇性应力.利用所得的奇性应力定义了裂纹和界面接触点处的动应力强度因子.对所得超奇异积分方程的数值求解可得裂纹端点和接解点处的应力强度因子。 相似文献
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采用Somigiliana公式给出了三维横观各向同性压电材料中的非渗漏裂纹问题的一般解和超奇异积分方程,其中未知函数为裂纹面上的位移间断和电势间断.在此基础上,使用有限部积分和边界元结合的方法,建立了超奇异积分方程的数值求解方法,并给出了一些典型数值算例的应力强度因子和电位移强度因子的数值结果,结果令人满意. 相似文献
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SCATTERING OF HARMONIC ANTI-PLANE SHEAR STRESS WAVES BY A CRACK IN FUNCTIONALLY GRADED PIEZOELECTRIC/PIEZOMAGNETIC MATERIALS 总被引:1,自引:0,他引:1
Liang Jun 《Acta Mechanica Solida Sinica》2007,20(1):75-86
In this paper, the dynamic behavior of a permeable crack in functionally graded piezoelectric/piezomagnetic materials is investigated. To make the analysis tractable, it is assumed that the material properties vary exponentially with the coordinate parallel to the crack. By using the Fourier transform, the problem can be solved with the help of a pair of dual integral equations in which the unknown is the jump of displacements across the crack surfaces. These equations are solved to obtain the relations between the electric filed, the magnetic flux field and the dynamic stress field near the crack tips using the Schmidt method. Numerical examples are provided to show the effect of the functionally graded parameter and the circular frequency of the incident waves upon the stress, the electric displacement and the magnetic flux intensity factors of the crack. 相似文献
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折线型裂纹对SH波的动力响应 总被引:1,自引:0,他引:1
利用Fourier积分变换方法,得出了无限平面中用裂纹位错密度函数表示的单裂纹散射场.根据无穷积分的性质,把单裂纹的散射场分解为奇异部分和有界部分.利用单裂纹的散射场建立了折线裂纹在SH波作用下的Cauchy型奇异积分方程.根据折线裂纹散射场和所得的积分方程讨论了裂纹在折点处的奇性应力及折点处的奇性应力指数.利用所得的奇性应力定义了折点处的应力强度因子.对所得Cauchy型奇积分方程的数值求解,可得裂纹端点和折点处的动应力强度因子. 相似文献
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A theoretical treatment of the scattering of anti-plane shear (SH) waves is provided by a single crack in an unbounded transversely
isotropic electro-magneto-elastic medium. Based on the differential equations of equilibrium, electric displacement and magnetic
induction intensity differential equations, the governing equations for SH waves were obtained. By means of a linear transform,
the governing equations were reduced to one Helmholtz and two Laplace equations. The Cauchy singular integral equations were
gained by making use of Fourier transform and adopting electro-magneto impermeable boundary conditions. The closed form expression
for the resulting stress intensity factor at the crack was achieved by solving the appropriate singular integral equations
using Chebyshev polynomial. Typical examples are provided to show the loading frequency upon the local stress fields around
the crack tips. The study reveals the importance of the electro-magneto-mechanical coupling terms upon the resulting dynamic
stress intensity factor.
Contributed by SHEN Ya-peng
Foundation item: the National Natural Science Foundation of China (10132010, 50135030)
Biographies: DU Jian-ke (1970∼) 相似文献
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SH波在正交各向异性功能梯度无限长条中心裂缝处的散射 总被引:3,自引:0,他引:3
研究了正交各向异性功能梯度材料无限长条中心裂缝对SH波的散射问题,为方便起见,材料两个方向的剪切模量和密度假定为指数模型.通过Fourier积分变换,将问题转化为对偶积分方程的求解.然后,用Copson方法求解对偶积分方程,定义了标准动应力强度因子,通过数值算例,讨论了在SH波作用下,裂缝尖端的标准动应力强度因子与入射波的频率、材料参数之间的关系. 相似文献
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The problem considered is a mode Ⅲ crack lying parallel to the interface of an exponential-type functional graded material (FGM) strip bonded to a linear-type FGM substrate with infinite thickness. By applying the Fourier integral transform, the problem was reduced as a Cauchy singular integral equation with an unknown dislocation density function. The collocation method based on Chebyshev polynomials proposed by Erdogan and Gupta was used to solve the singular integral equation numerically. With the numerical solution, the effects of the geometrical and physical parameters on the stress intensity factor (SIF) were analyzed and the following conclusions were drawn: (a) The region affected by the interface or free surface varies with the material rigidity, and higher material rigidity will lead to bigger affected region. (b) The SIF of the crack in the affected region and parallel to the micro-discontinuous interface is lower than those of the weak discontinuous cases. Reducing the weak-discontinuity of the interface will be beneficial to decrease the SIF of the interface-parallel crack in the region affected by the interface. (c) The effect of the free surface on SIF is more remarkable than that of the interface, and the latter is still more notable than that of the material rigidity. When the effects of the interface and free surface are fixed, increase of the material rigidity will enhance the value of SIF. 相似文献
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论文采用了一种新的方法求解含孔元发域的反平面剪切问题,以闭合形式导出了在集中力作用下,孔口尖点的应力强度因子表达式。同时,给出了对称翼状尖孔、内摆线状尖孔、震状尖孔及圆孔径向边裂纹的应力强度因子,其结果在理论上和应用中都具有重要的意义。 相似文献
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孔边裂纹对SH波的散射及其动应力强度因子 总被引:14,自引:1,他引:14
采用Green函数法研究任意有限长度的孔边裂纹对SH波的散射和裂纹尖端场动应力强度因子的求解.取含有半圆形缺口的弹性半空间水平表面上任意一点承受时间谐和的出平面线源荷载作用时位移函数的基本解作为Green函数,采用裂纹“切割”方法并根据连接条件建立起问题的定解积分方程,得到动应力强度因子的封闭解答.最后给出了孔边裂纹动应力强度因子的算例和结果,并讨论了圆孔的存在对动应力强度因子的影响 相似文献
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THREE-DIMENSIONAL INTERACTIONS OF A HALF-PLANE CRACK IN A TRANSVERSELY ISOTROPIC PIEZOELECTRIC SPACE WITH RESULTANT SOURCES 总被引:2,自引:0,他引:2
Hou Pengfei Pan Xiaoping Ding Haojiang 《Acta Mechanica Solida Sinica》2005,18(3):265-271
I. INTRODUCTIONBecause of the widespread application and intrinsic brittleness of piezoelectric ceramics, significantattention is being paid to the crack problems of piezoelectric ceramics. The last decade has seen a lotof three-dimensional studies of crack in piezoelectric ceramics[1??9]. In addition, the electroelastic fieldin a transversely isotropic piezoelectric space with a half-plane crack subjected to symmetric normalpoint forces, antisymmetric tangential point forces and point ch… 相似文献
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横观各向同性液体饱和多孔介质中平面波的传播 总被引:11,自引:2,他引:11
基于孔隙介质的Biot理论1,研究了横观各向同性液体饱和多孔介质中平面波的传播特性。首先导出了波传播的特征方程并给出了其解析解,结果显示:有4种不同波速的平面体波传播;第一准纵波,第二准纵波,准横波和反平面横波。文中给出了波速和衰减的解析表达式,数值计算了频散曲线和衰减曲线,并讨论了各类准体波位移之间的耦合关系。 相似文献
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Exact solutions in form of elementary functions were derived for the stress and electric displacement intensity factors of a circular crack in a transversely isotropic piezoelectric space interacting with various stress and charge sources: force dipoles, electric dipoles, moments, force dilatation and rotation. The circular crack includes penny-shaped crack and external circular crack and the locations and orientations of these resultant sources with respect to the crack are arbitrary. Such stress and charge sources may model defects like vacancies, foreign particles, and dislocations. Numerical results are presented at last. 相似文献
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IntroductionItiswell_knownthatpiezoelectricmaterialsproduceanelectricfieldwhendeformedandundergodeformationwhensubjectedtoanelectricfield .Thecouplingnatureofpiezoelectricmaterialshasattractedwideapplicationsinelectro_mechanicalandelectricdevices,suchaselectro_mechanicalactuators,sensorsandstructures.Whensubjectedtomechanicalandelectricalloadsinservice,thesepiezoelectricmaterialscanfailprematurelyduetodefects,e .g .,cracks,holds,etc.arisingduringtheirmanufactureprocess.Therefore,itisofgreatimp… 相似文献
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川藏公路地质环境与整治改建方案的思考 总被引:3,自引:1,他引:3
川藏公路由于地质环境复杂、建设标准低、后遗病害多,抗灾能力差,泥石流、滑坡、山崩、雪害、水毁等自然灾害频繁发生,公路阻车断道严重。国家投入巨资进行整治改建,并取得了明显的效果,但由于自然环境特殊、影响因素复杂,许多特大型、大型工程地质病害问题还没有可行、可靠的解决方案。本文通过分析川藏公路沿线的地质环境和灾害特点,总结历年整治改建和经验的教训,提出川藏公路建设的途径、可能达到的目标和应采用的原则。 相似文献
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In this paper, the interaction between two collinear cracks in piezoelectric materials under anti-plane shear loading was
investigated for the impermeable crack face conditions. By using the Fourier transform, the problem can be solved with two
pairs of triple integral equations. These equations are solved using Schmidt's method. This process is quite different from
that adopted previously. This study makes it possible to understand the two collinear cracks interaction in piezoelectric
materials.
The authors are grateful for financial support from the Post-Doctoral Science Foundation and the Natural Science Foundation
of Heilongjiang Province. 相似文献
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处理了无界体中一无限长、有限宽的平面应变裂纹,对任意入射膨胀波的散射问题.这里采用了Wiener-Hopf技术及标准迭代方法,得到了二次反射波到达后的应力强度因子的解析表达式,并给出了数值结果。 相似文献
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应变波对岩体的损伤作用和爆生裂纹传播 总被引:12,自引:1,他引:12
给出了应变波作用下岩体损伤累积计算方法,将爆破过程中应变波的动作用和爆生气体的准静压作用结合起来,分析爆生裂纹传播的全过程,修正了以往理论,井揭示了Kut-ter等人所说的应力波对岩体预载荷作用 ̄[1]的力学本质。 相似文献