正交异性双材料的Ⅱ型界面裂纹尖端场

通过引入含16个待定实系数和两个实应力奇异指数的应力函数,再借助边界条件,得到了两个八元非齐次线性方程组.求解该方程组,在双材料工程参数满足适当条件下,确定了两个实应力奇异指数.根据极限唯一性定理,求出了全部系数,得到了应力函数的表示式.代入相应的力学公式,推出了当特征方程组两个判别式都小于0时,每种材料的裂纹尖端应力强度因子、应力场和位移场的理论解.裂纹尖端附近的应力和位移有混合型断裂特征,但没有振荡奇异性和裂纹面相互嵌入现象作为特例,当两种正交异性材料相同时,可以推出正交异性单材料Ⅱ型断裂的应力奇异指数、应力强度因子公式、应力场、位移场表示式.     

碳纤维增强复合材料板中Ⅰ型裂纹扩展方向预测理论研究

对含裂纹碳纤维增强的复合材料层合板进行了裂纹扩展方向预测理论的研究．介绍了一种新的复合材料Z断裂理论，在裂纹尖端Z因子的定义中引入了新概念：面内平均应变，面内膨胀应变能密度因子和交互特征函数．并通过理论分析和实验测试证明了Z断裂理论的正确性．     

A STUDY OF J-INTEGRAL OF THE ORTHOTROPIC COMPOSITE MATERIAL

ＡＳＴＵＤＹＯＦＪ－ＩＮＴＥＧＲＡＬＯＦＴＨＥＯＲＴＨＯＴＲＯＰＩＣＣＯＭＰＯＳＩＴＥＭＡＴＥＲＩＡＬＷａｎｇＡｉ－ｑｉｎ（王蔼勤）；ＦｅｎｇＢａｏ－ｌｉａｎ（冯宝莲）；ＹａｎｇＷｅｉ－ｙａｎｇ（杨维阳）（ＴａｉｙｕａｎＨｅａｖｙＭａｃｈｉｎｅｒｙ．...     

PREDICTION OF MODE Ⅰ CRACK PROPAGATION DIRECTION IN CARBON-FIBER REINFORCED COMPOSITE PLATE

A newly developed Z fracture criterion for the composite materials was introduced,the new concepts of in-plane average strain,in-plane dilatational strain energy density factor and reciprocal characteristic function were presented.Many experimental results show that the Z fracture criterion can be well used to predict the crack propagating direction for mode Ⅰ crack in carbon-fiber reinforced composite laminates.     

正交异性双材料半无限界面裂纹尖端场分析

通过构造含两个实奇异指数的应力函数,利用复合材料断裂复变方法对正交异性双材料界面裂纹进行了研究。在特征方程组的判别式都小于零的情况下,通过求解一类广义重调和方程组边值问题,在双材料工程参数满足适当的条件下,推出了正交异性双材料半无限界面裂纹尖端的应力场和位移场。研究表明:其结果没有振荡奇异性;当上下半平面材料参数相同时,可获得正交异性单材料的应力场。并通过有限元算例进行比较,验证了理论结果的正确性。     

Interface crack problems for mode II of double dissimilar orthotropic composite materials

The fracture problems near the similar orthotropic composite materials are interface crack tip for mode Ⅱ of double disstudied. The mechanical models of interface crack for mode Ⅱ are given. By translating the governing equations into the generalized hi-harmonic equations, the stress functions containing two stress singularity exponents are derived with the help of a complex function method. Based on the boundary conditions, a system of non-homogeneous linear equations is found. Two real stress singularity exponents are determined be solving this system under appropriate conditions about bimaterial engineering parameters. According to the uniqueness theorem of limit, both the formulae of stress intensity factors and theoretical solutions of stress field near the interface crack tip are derived. When the two orthotropic materials are the same, the stress singularity exponents, stress intensity factors and stresses for mode II crack of the orthotropic single material are obtained.     

Crack-tip field on mode Ⅱ interface crack of double dissimilar orthotropic composite materials

Two systems of non-homogeneous linear equations with 8 unknowns are obtained.This is done by introducing two stress functions containing 16 undetermined coefficients and two real stress singularity exponents with the help of boundary conditions.By solving the above systems of non-homogeneous linear equations,the two real stress singularity exponents can be determined when the double material parameters meet certain conditions.The expression of the stress function and all coefficients are obtained based on the uniqueness theorem of limit.By substituting these parameters into the corresponding mechanics equations,theoretical solutions to the stress intensity factor,the stress field and the displacement field near the crack tip of each material can be obtained when both discriminants of the characteristic equations are less than zero.Stress and displacement near the crack tip show mixed crack characteristics without stress oscillation and crack surface overlapping.As an example,when the two orthotropic materials are the same,the stress singularity exponent,the stress intensity factor,and expressions for the stress and the displacement fields of the orthotropic single materials can be derived.     

The crack tip fields of orthotropic composite plate under bending

1MechhacalModelThefractUreproblemwhichisthesameasthatinpaper[I]isfurtherdiscussedinthispaper.TheanalysisoffractUrebehavioursnearcracktipforinfinitelinearelasticorthotropiccompositeplatewithacentralthroughcrackoflengthZaiscarriedout.ThegeometryandloadingcondihonsareshowninFig.1.Tosolvesuchaproblem,weneedtosolvethepanaldifferentialequationwiththefollowingboundaryconditions:wherewisdeflectionofcoddleplane;M.andM,arebendingmoment,Ma.istwistingmoment,andstiffnessmatrixFromthetheoryofplateL'],w…     

复合材料平面断裂中的J积分

本文采用复变函数方法,首先将裂纹尖端应力和位移代入J积分的一般公式得到了线弹性正交异性复合材料单向板复合型裂纹尖端的J积分的复形式,其次证明了该J积分的路径无关性,最后推出了该J积分的计算公式.作为特例,给出了线弹性正交异性复合材料单向板Ⅰ,Ⅱ型裂纹尖端的J积分的复形式,路径无关性和计算公式.