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1.
本文研究了具有中心孔的正交复合材料板在双向载荷下的应力,建立了有限校核系数和双轴率以及之间板宽率的关系,并得到孔边的应力集中系数.这些结果对研究具有中心孔的正交复合材料板在双向载荷下的强度预测和应力分析具有重要的作用. 相似文献
2.
M. P. Malezhik I. S. Chernyshenko G. P. Sheremet 《International Applied Mechanics》2007,43(7):767-771
Photoelastic plates made of an orthotropic material are used to model the dynamic stress state near free and reinforced circular
holes under blast loading. The diffraction of stress waves by holes in a thin-walled plate is studied. Experimental data are
used to analyze the dynamic stress concentration in a plate with a hole in which quasilongitudinal and quasitransverse waves
propagate
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Translated from Prikladnaya Mekhanika, Vol. 43, No. 7, pp. 73–78, July 2007. 相似文献
3.
运用一种改进的非结构化四边形格子法,对含孔正交各向异性板条受面内冲击拉伸时弹性应力波的传播过程和孔边的动应力集中进行了研究.非结构化格子法采用与有限元类似的网格剖分方法,并基于围绕每个节点的积分平衡方程,并自然满足复杂边界的自由边界条件.计算中不需存储刚度矩阵,因而计算速度快、效率高、节省内存,在解决应力波传播问题中具有显著的优越性.通过对多种工况进行数值模拟,分析了材料的各向异性性质、纤维方向、孔径比、加载脉冲周期等参数对孔边动应力的影响,得到了一些规律性的结果.并与现有实验结果进行对比,验证了该方法的有效性. 相似文献
4.
A triangular grid method is presented to calculate propagation problems of elastic stress waves in 2-D orthotropic materials. This method is based on the dynamic equilibrium equations of the computational cells formed among the auxiliary triangular grids. The solution is obtained by calculating alternately the nodal displacements and the central point stresses of the spatial grids. The numerical results are compared with the corresponding solutions of the finite element method. Comparisons show that the triangular grid method yields a higher calculational speed than the finite element method. The stress concentrations are investigated from wave-field analyses when the stress wave propagates within an orthotropic plate with a hole. Finally, the presented numerical method is used to study the features of wave propagation and diffraction in a square orthotropic plate with a hole when an impact load is applied to the top of the plate.This work was supported by National Natural Science Foundation of China (Nos. 10025212 and 10232040) and Natural Science Foundation of Liaoning province (No. 20021070). 相似文献
5.
本文提出一个计及轴销变形与接触区摩擦效应的弹性轴销模型,并采用弹性理论的复变函数解法,研究了正交各向异性无限大板的孔销接触问题.分析表明,板件的孔边应力分布与板件、轴销的材料性能密切相关,而且,摩擦系数的大小对应力分布也存在明显影响. 相似文献
6.
正交异性动态光弹性方法的几个基本问题的研究 总被引:2,自引:0,他引:2
文章对适用于动态研究的正交异性光弹性复合材料进行了分析,详细说明了光弹性复合材料中残余双折射的确定方法;基于静态下Hyer和Liu应力-光性定律,提出了正交异性动态应力-光性定律,并对正交异性材料的动态力学参数及动态光弹性常数给出了实用的标定方法;最后,利用三个单轴压缩试件(0°,90°及45°),采用动态应变测量方法,证实了单轴应力状态下正交异性动态应力-光性定律的正确性。 相似文献
7.
ABSTRACT This investigation deals with the nonlinear axisymmetric static and transient response of orthotropic annular shallow spherical caps with a free edge hole and with a rigid central mass, subjected to uniformly distributed load and a central load. The dynamic analogue of Marguerre equations, in terms of normal displacement w and stress function Ψ, are employed. An orthogonal point collocation method is used for spatial discretization and a Newmark-β scheme is used for time integration. Static load, step function load, and sinusoidal pulse load are considered. The influence of annular ratio on the response is studied for isotropic (β = 1) and orthotropic (β = 3) clamped caps, with a rise to thickness ratio of 1.5. 相似文献
8.
Liu Diankui 《Acta Mechanica Sinica》1988,4(2):146-155
A new approach based on complex function to solve the SH-wave scattering problem around a circular hole in anisotropic media
is introduced in this paper. It is found that the dynamic stress concentration factor is dependent on the incident wave number
and the hole radius. Finally, some numerical results of dynamic stress concentration factor of a circular hole in anisotropic
media are given.
The Project Supported by National Natural Science Foundation of China 相似文献
9.
Based on the two-dimensional theory of elasticity for an orthotropic plate, relations between stress components produced in
two different orthotropic plates are considered and the conditions to realize the similar stress fields in different orthotropic
plates are studied. On the basis of the similarity law, a convenient photoelastic method to analyze stress fields in an orthotropic
plate, using an isotropic plate, is presented. Two examples are treated. One deals with the stress-concentration problem around
a circular hole in a strip with edges parallel to the symmetric axis of elasticity. In the second example, the edges of the
strip are assumed to be inclined by 30 deg to the elastically symmetric axes. The experimental results are compared with theoretical
calculations.
Paper was presented at the SEM VII International Congress on Experimental Mechanics held in Las Vegas, NV on June 8–11, 1992. 相似文献
10.
《International Journal of Solids and Structures》2007,44(25-26):8244-8258
This paper is the second part of a work that analyses the problem of residual stress determination in an orthotropic material by the hole drilling technique combined with full field optical methods. Due to the complex behaviour of the material, two theoretical formulations capable of describing the displacement field in an infinite plate in tension with a hole have been proposed: a simplified one, which can treat only a subset of all orthotropic materials, and a general, much more complex one. In the first part of this work, it has been shown that by using the simplified formulation, it is possible to develop a linear least square approach to the residual stress identification problem capable of treating a large class of orthotropic materials. This second part shows that the same approach can be extended to the general case providing that a somewhat more complex, nonlinear algorithm, is acceptable. 相似文献
11.
The present study deals with the development and the application of the through-hole drilling method for the residual stress
analysis in orthotropic materials. Through a systematic theoretical study of the stress field present on orthotropic plates
with a circular hole, the relationships between the relaxed strains measured by a rectangular strain gauge rosette and the
Cartesian components of the unknown residual stresses are obtained. The theoretical formulas of each influence coefficient
allow the user an easy application of the method to the analysis of uniform-residual stresses on a generic homogeneous orthotropic
material. Furthermore, to extend the method to the analysis of the residual stresses on orthotropic laminates, caused by initial
in-plane loadings, an alternative formulation is implemented. The accuracy of the proposed method has been assessed through
3D numerical simulations and experimental tests carried out on unidirectional, cross-ply and angle-ply laminates. 相似文献
12.
基于线性压电动力学理论,采用波函数展开法、保角映射以及复变函数,对含非圆孔洞无限大压电薄板弹性波的散射及动应力集中问题进行了分析,给出了其动弯矩集中系数(DMCF)的解析表达式.为说明问题,以PZT-4为例,讨论了外加电场、椭圆孔长短半轴比、椭圆孔倾角以及入射波频率对含圆孔和椭圆孔无限大压电薄板弹性波散射的影响,并分别... 相似文献
13.
J. F. Cárdenas-García S. Ekwaro-Osire J. M. Berg W. H. Wilson 《Experimental Mechanics》2005,45(4):301-313
The hole method problem relates to two inverse problems of interest: the first, most commonly addressed by practitioners,
is to obtain residual stresses; the other, generally neglected, inverse problem can be posed as either a stress separation
problem or a material elastic properties identification problem. In both this Paper I and Paper II, we pose and solve this
dual hole method problem in an orthotropic plate, using computer generated moiré isothetics, by means of a non-linear least-squares
approach. In Paper I we address the residual stress problem. In Paper II we pose the use of moiré isothetics as a means to
achieve separation of stresses, but we deal with the determination of the five orthotropic elastic constants, four of which
are independent. 相似文献
14.
15.
Both the orthotropy and the stress concentration are common issues in modern structural engineering. This paper introduces
the boundary element method (BEM) into the elastic and elastoplastic analyses for 2D orthotropic media with stress concentration.
The discretized boundary element formulations are established, and the stress formulae as well as the fundamental solutions
are derived in matrix notations. The numerical procedures are proposed to analyze both elastic and elastoplastic problems
of 2D orthotropic media with stress concentration. To obtain more precise stress values with fewer elements, the quadratic
isoparametric element formulation is adopted in the boundary discretization and numerical procedures. Numerical examples show
that there are significant stress concentrations and different elastoplastic behaviors in some orthotropic media, and some
of the computational results are compared with other solutions. Good agreements are also observed, which demonstrates the
efficiency and reliability of the present BEM in the stress concentration analysis for orthotropic media.
The project supported by the Basic Research Foundation of Tsinghua University, the National Foundation for Excellent Doctoral
Thesis (200025) and the National Natural Science Foundation of China (19902007). The English text was polished by Keren Wang. 相似文献
16.
The results obtained in developing and applying the method of dynamic photoelasticity to two-dimensional problems in the mechanics
of anisotropic bodies are reviewed. The theory behind the method and its engineering implementation are described. The capabilities
of the method are illustrated by solving specific nonstationary problems: dynamic stress concentration, diffraction of longitudinal
and transverse waves by free and reinforced holes, dynamic fracture of orthotropic plates with holes and cracks under impulsive
and explosive loads 相似文献
17.
The photoelastic method is used to analyze the stress–strain state induced by an impulsive load in an orthotropic plate with circular holes. The distribution of dynamic stress concentration factors along the periphery of the holes is studied, and stresses and strains in representative sections are determined 相似文献
18.
In the present paper dynamic stress intensity factor and strain energy density factor of multiple cracks in the functionally graded orthotropic half-plane under time-harmonic loading are investigated. By utilizing the Fourier transformation technique the stress fields are obtained for a functionally graded orthotropic half-plane containing a Volterra screw dislocation. The variations of the material properties are assumed to be exponential forms which the equilibrium has an analytical solution. The dislocation solution is utilized to formulate integral equation for the half-plane weakened by multiple smooth cracks under anti-plane deformation. The integral equations are of Cauchy singular type at the location of dislocation which are solved numerically to obtain the dislocation density on the faces of the cracks. The dislocation densities are employed to determined stress intensity factor and strain energy density factors (SEDFs) for multiple smooth cracks under anti-plane deformation. Numerical examples are provided to show the effects of material properties and the crack configuration on the dynamic stress intensity factors and SEDFs of the functionally graded orthotropic half-plane with multiple curved cracks. 相似文献
19.
周次青 《应用数学和力学(英文版)》1985,6(8):801-810
This paper presents the standard parametric representation of the Tsai-Hill yieldcriterion in a state of plane stress and the equations governing the stress distribution in acylindrically orthotropic composite lamina with a circular hole under uniform pressure forthe three cases: (a) elastic state.(b) limit state and (c) elastoplastic state. The formulasfor the yield pressure and the limit pressure have been obtained. 相似文献
20.
Stress state around cracks on the boundary of a hole in a photoelastic orthotropic plate under creep
The stress–strain state near cracks on the boundary of a circular hole in a linear elastic orthotropic composite plate under
tension is analyzed. The distribution of stress intensity factors (SIFs) at the crack tip is found from photoelectric measurements.
The dependence of the SIFs on the ratio of crack length to hole radius and on the mechanical properties of the material is
established 相似文献