共查询到20条相似文献,搜索用时 109 毫秒
1.
2.
正交异性复合材料界面上反平面动态自相似扩展裂纹问题的解 总被引:2,自引:0,他引:2
采用复变函数论的方法,对复合材料界面上的裂纹扩展问题进行研究。并根据任意的自相似指数的断裂动力学问题,进行自相似求解,导出解析解的一般表示。应用该法可以迅速地将所论问题转化为Riemann-Hil-bert问题,并可以相当简单地得到问题的闭合解。文中分别对裂纹中心受阶跃载荷,裂纹面受到瞬时脉冲载荷作用下的界面裂纹扩展问题进行求解。得到了裂纹的位移。尖端的应力和动态应力强度因子的解析解。应用该解并通过叠加原理。就可以很容易的求得任意复杂问题的解。 相似文献
3.
采用复变函数论,对反平面条件下的动态裂纹扩展问题进行研究。通过自相似函数的方法可以获得解析解的一般表达式。应用该法可以很容易地将所讨论的问题转化为Riemann—Hilbert问题,并可以相当简单地得到问题的闭合解。文中分别对裂纹面受均布载荷、坐标原点受集中增加载荷、坐标原点受瞬时冲击载荷以及裂纹面受运动集中载荷Px/t作用下的动态裂纹扩展问题进行求解,得到了裂纹扩展位移、裂纹尖端的应力和动态应力强度因子的解析解。应用该解并通过叠加原理,就可以求得任意复杂问题的解。 相似文献
4.
5.
通过复变函数论的方法,对非对称Ⅲ型界面裂纹扩展的动态问题进行了研究.采用自相似函数的方法可以轻易地将所论问题转化为Riemann-Hilbert问题,并求得了裂纹坐标原点分别受到变载荷$Pt/ x$, $Px^3 /t^2$作用下的解析解的一般表达式.通过Muskhelishvili方法可以相当简单地得到问题的闭合解. 利用这些解并采用叠加原理,可以求得任意复杂问题的解. 相似文献
6.
复合材料产生裂纹后,其纤维处形成“桥连”,这是一个不可避免的现象。由于桥连问题很复杂,在数学方法的处理上有很大困难,至今人们研究的大多是桥连的静力学问题,而对其动力学问题研究得很少。只有建立复合材料的桥连动力学模型,才能更好地研究复合材料的断裂动力学问题。为了便于分析复合材料的问题,将桥连处用载荷代替,当裂纹高速扩展时,其纤维也连续地断裂。通过复变函数论的方法,将所讨论的问题转化为Riemann-Hilbet问题。利用建立的动态模型和自相似方法,得到了正交异性体中扩展裂纹受运动的集中力Px/t及均布载荷作用下位移、应力和动态应力强度因子的解析解,并通过迭加原理,最终求得了该模型的解。 相似文献
7.
复合材料桥连的断裂动力学模型 总被引:8,自引:0,他引:8
复合材料产生裂纹后,其纤维处形成“桥连”,这是一个不可避免的现象。由于桥连问题很复杂.在数学方法的处理上有很大困难,至今人们研究大多是桥连的静力学问题.而对其动力学问题研究得很少。为了便于分析复合材料的问题,将桥连处用载荷代替,当裂纹高速扩展时.其纤维也连续地断裂。只有建立复合材料的桥连动力学模型,才能更好地研究复合材料的断裂动力学问题。通过复变函数论的方法,将所讨论的问题转化为Riemann—Hilbert问题。利用建立的动态模型和自相似方法,得到了正交异性体中扩展裂纹受运动的集中力P及阶跃载荷作用下位移、应力和动态应力强度因子的解析解,并通过叠加原理,最终求得了该模型的解。 相似文献
8.
9.
冲击下两种正交异性材料界面上的扩展裂纹问题 总被引:1,自引:0,他引:1
本文给出了正交异性体反平面问题波动方程的函数不变解。基于这个解,文中导出了具有任意自相似指数的正交异性体反平面弹性动力学问题的一般解。变量t的任意连续函数在任意闭域中都可以用t0ln的多项式来一致地逼近。利用复变函数理论,我们将不同正交异性材料界面上受t0ln型及1(l)型载荷作用的扩展裂纹问题化为解析函数论中的Keldysh-Sedov混合问题。并给出了这类问题的闭合解。 相似文献
10.
11.
This paper analyzes the anti-plane problem of dynamic self-similar debonding of interface at very high velocity. The debonding is modeled as an interface crack propagating self-similarly from zero-length. The extending speed is assumed to be transonic or supersonic. We first consider the dynamic debonding under moving concentrated loads. The moving dislocation model of self-similar propagation of an interface crack is used to formulate the problem to a singular integral equation which is solved analytically. The singularity of stresses near the crack tip is discussed and the dynamic stress intensity factors are presented. Finally the solution of dynamic debonding underx
2-type loads is obtained by using the superposition method. 相似文献
12.
DYNAMIC ANALYSIS OF A BURIED RIGID ELLIPTIC CYLINDER PARTIALLY DEBONDED FROM SURROUNDING MATRIX UNDER SHEAR WAVES 总被引:2,自引:0,他引:2
Wang Yuesheng Wang Duo Department of Astronautics Mechanics Harbin Institute of Technology Harbin P. R. China 《Acta Mechanica Solida Sinica》1995,8(1):51-63
This paper investigates the dynamic behavior of a buried rigid ellipticcylinder partially debonded from surrounding matrix under the action of anti-planeshear waves (SH waves). The debonding region is modeled as an elliptic arc-shapedinterface crack with non-contacting faces. By using the wave function (Mathieufunction) expansion method and introducing the dislocation density function as anunknown variable, the problem is reduced to a singular integral equation which issolved numerically to calculate the near and far fields of the problem. The resonanceof the structure and the effects of various parameters on the resonance are discussed. 相似文献
13.
剪切波作用下埋藏刚性椭圆柱与周围介质部分脱胶时的动力分析 总被引:1,自引:0,他引:1
本文利用波函数展开法和奇异积分方程技术研究了SH型反平面剪切波作用下埋藏刚性椭圆柱与周围介质部分脱胶时的动力特性.将脱胶区看作表面不相接触的椭圆弧形界面裂纹,利用波函数(Mathieu函数)展开法,并引人裂纹面的位错密度函数为未知量,将问题归结为奇异积分方程,通过数值求解积分方程获得了远场和近场物理参量,并讨论了共振特性和各参数对共振的影响. 相似文献
14.
The singularity behavior of a crack on the interface of two different media under dynamic load is investigated. By introducing a small region in which the crack faces make frictionless contact and making use of a kind of integral equations with moving boundaries, it is proved that there are only square-root singularities near the interface crack tips in case that a dynamic load acts on it. Numerical results show that the normal stress in the contact region remains negative. The results of the stress intensity factor and the length of the crack face contact region are given to illustrate the dynamic behavior of the interface crack.This work is supported by the National Natural Science Foundation of China. 相似文献
15.
本文求解了弹性P波对界面部分脱胶的可动刚性圆柱夹杂物的散射问题。将脱胶区看作表面不相接触的弧形界面裂纹,借助波函数展开法并利用边界条件将问题转化为一组对偶级数方程。然后通过引入裂纹面的位错密度函数,将其化为一组具有Hilbert核的第二类奇异积分方程,并进一步化为Cauchy型奇异积分方程组,数值求解方程组可获得动应力强度因子,夹杂物刚体振动位移和散射截面等重要参量。结果显示该类结构在较低的频率上发生共振,此低频共振特性与脱胶区大小,入射波方向、材料组合等多种参数有关。与已有方法相比,本文的方法更具一般性,适用于任意材料组合。 相似文献
16.
《International Journal of Solids and Structures》2006,43(21):6535-6550
When a crack propagates towards a weak interface, interface debonding may occur before the incident crack reaches the interface. This phenomenon refers to the “Cook–Gordon mechanism”. In this investigation, an equivalent dynamic Cook–Gordon mechanism is studied both experimentally and analytically. Two strength-based criteria incorporating dynamic fracture mechanics analysis are proposed to predict the initiation location of interface debonding ahead of a dynamic incident crack. As validation, a comparison is made between the analytical predictions and experimental measurements. Results show that the strength-based criteria can effectively predict the initiation of interface debonding. Meanwhile, effects of the stress intensity factor and the T stress of the incident crack, on the interfacial debonding initiation are investigated. It is concluded that high-stress intensity factors of the incident cracks will easily induce interfacial debonding initiation, and changing the T stress is an effective way to control interfacial debonding initiation. Furthermore, high-interfacial tensile strengths rather than shear strengths, tend to suppress interfacial debonding initiation induced by a mode-I incident crack. 相似文献
17.
18.
本文研究了界面裂纹尖端的动态应力场的奇异特性.引入尖端无摩擦接触的界面裂纹模型并采用具有运动边界的控制积分方程.证明了在动态界面裂纹尖端仅存在平方根奇异的应力场.数值结果表明接触区中的正应力确保持为压应力.为表现界面裂纹的动态特性,给出了应力强度因子和裂纹面接触区尺寸的数值结果. 相似文献
19.
K. P. Herrmann V. V. Loboda A. V. Komarov 《Archive of Applied Mechanics (Ingenieur Archiv)》2004,74(1-2):118-129
Summary A plane strain problem for a crack with a frictionless contact zone at the leading crack tip expanding stationary along the
interface of two anisotropic half-spaces with a subsonic speed under the action of various loadings is considered. The cases
of finite and infinite-length interface cracks under the action of a moving concentrated loading at its faces are considered.
A finite-length crack for a uniform mixed-mode loading at infinity is considered as well. The associated combined Dirichlet-Riemann
boundary value problems are formulated and solved exactly for all above-mentioned cases. The expressions for stresses and
the derivatives of the displacement jumps at the interface are presented in a closed analytical form for an arbitrary contact
zone length. Transcendental equations are obtained for the determination of the real contact zone length, and the associated
closed form asymptotic formulas are found for small values of this parameter. It is found that independently of the types
of the crack and loading, an increase of the crack tip speed leads to an increase of the real contact zone length and the
correspondent stress intensity factor. The latter increase significantly for an interface crack tip speed approaching the
Ragleigh wave speed. 相似文献
20.
不同压电介质界面上的反平面运动裂纹 总被引:1,自引:1,他引:0
利用积分变换技术,得到不同压电介质界面上的平面运动裂纹问题的分析解。结果表明应力及电位移强度因子均与界面裂纹扩展速度及材料参数相关,这不同于均匀压电介质中运动裂纹的结论,当两种压电介质完全相同时,本文结果将退化为均匀压电介质中反平面运动裂纹问题的解。 相似文献