共查询到19条相似文献,搜索用时 879 毫秒
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基于断裂能的岩土节理弹性-软化塑性本构模型 总被引:1,自引:0,他引:1
基于准脆性材料的断裂力学和塑性理论,提出了用于岩土节理软化行为描述的弹性软化塑性本构模型.模型的主要特点是:1)节理材料的软化塑性和扩容特性直接与断裂失效过程相联系,所采用的材料参数比已有的弹塑性软化模型所用的参数少;2)模型可以描述混合断裂失效及相应的摩擦滑动,具有较广的适用性. 相似文献
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塑性全量理论的变分不等式模式及其无迭代解 总被引:1,自引:0,他引:1
变分不等式是解决一类带单侧约束的定常力学问题的有效数学工具.本文就弹塑性全量理论构造了等价的变分不等式模式,解除了弹塑性问题本构约束的不等式关系,比一般能量形式的描述更为简洁.它便于计算,具有可靠的数学依据,可以用二次规划法求解.计算时无需分级加载迭代,一步即可得收敛解. 相似文献
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一种基于虚功原理的求解弹塑性问题的有限元——数学规划法* 总被引:1,自引:1,他引:0
本文通过将屈服函数按台劳级数展开,并略去二阶以上高阶项,从而将弹塑性本构方程写为线性互补形式这一思路,从熟知的虚功原理出发,结合有限元离散技术,简捷地得到了一种求解弹塑性力学问题的线性互补方法.所得方法可用于满足关联及非关联流动法则的材料.另外,本文还讨论了该方法解的存在性唯一性问题,给出了几个有用的结论. 相似文献
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耦合热弹塑性问题的泛函及其变分原理* 总被引:1,自引:0,他引:1
为用有限元法求解耦合热弹塑性问题,建立适当的泛函是有必要的.本文试图在K.N.Rysinko和E.I.Blinov提出的热弹塑性本构方程和热传导方程[1]的基础上,用泛函分析理论导出耦合热弹塑性问题的泛函. 相似文献
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《数学的实践与认识》2020,(15)
主要针对在求解粘性Cahn-Hilliard方程时非线性项引起的时间耗时问题,提出了时间双层网格混合有限元方法.在空间上采用混合有限元方法进行离散,时间上采用Crank-Nicolson格式.首先在时间粗网格上,通过非线性牛顿迭代方法求解非线性混合有限元系统.其次基于初始迭代数值解和拉格朗日插值公式在时间细网格上求解线性混合有限元系统,然后证明了该方法的稳定性和误差估计,并通过数值算例对理论部分进行验证.结果表明,理论与数值算例相一致. 相似文献
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裂纹线场分析方法目前已发展成为裂纹弹塑性分析的一种独立方法,这一方法极大地简化了裂纹弹塑性问题的复杂性和数学上的困难,可求出各型裂纹的弹塑性场在裂纹线附近足够精确的解答,但是,以前采用这一方法求解时,均是针对一些具体问题进行的,没有给出裂纹线附近弹塑性分析的一般步骤和匹配方程的一般形式。该文针对理想弹塑性I型平面应力裂纹问题,按线场分析方法,给出了裂纹线附近弹塑性分析一般步骤,并针对一具体问题,给出了求解的过程和结果。 相似文献
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《数学的实践与认识》2020,(18)
提出了一种基于Legendre正交函数求解对流扩散方程的无条件稳定方法.方法将对流扩散方程中的各项基于Legendre基函数进行展开,利用各阶基函数的正交性质和Galerkin方法消除方程中的时间微分项,形成可求解的系数矩阵方程,最后通过求解各阶展开系数可重构数值结果.为全面评价该方法,分别设计了具有精确解的一维方程和具有精细结构的二维问题等2个算例.计算结果表明:方法能够实现无条件稳定,且具有较高精度,同时在求解含有精细结构的对流扩散问题时具有明显的效率优势. 相似文献
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S. K. Godunov I. M. Peshkov 《Computational Mathematics and Mathematical Physics》2010,50(8):1409-1426
The paper is devoted to new applications of the ideas underlying Godunov’s method that was developed as early as in the 1950s
for solving fluid dynamics problems. This paper deals with elastoplastic problems. Based on an elastic model and its modification
obtained by introducing the Maxwell viscosity, a method for modeling plastic deformations is proposed. 相似文献
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为了分析及深入探讨混凝土在受拉加载及卸载情况下的力学特性,基于随机损伤本构关系提出了一种混凝土轴拉加卸载模型,推导出了混凝土加卸载的应力 应变关系表达式.为了印证理论表达式,进行了混凝土轴向拉伸及加卸载的试验研究,测得了混凝土的材料参数及其相应的轴拉加卸载应力-应变曲线.结合模型的计算结果,对混凝土的轴拉加卸载试验结果进行了对比分析,结果表明:混凝土轴拉加卸载模型能够预测混凝土的极限强度,同时能描述混凝土的强度软化、加载过程中的弹模折减及卸载后的塑性变形. 相似文献
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The problem of surface instability of laminated coatings with inelastic properties is considered within the framework of a model of piecewise-homogeneous media on the basis of the three-dimensional linearized theory of stability. A general statement of the problem is formulated and the basic characteristic equations are derived. The solutions of particular problems are obtained for elastoplastic and viscoelastic models of solids. 相似文献
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基于不可逆热力学理论和内变量理论,提出平均意义下的Clausius_Duhem不等式方程·与以往弹塑性空洞损伤研究不同,本文旨在利用自洽分析法建立起既考虑空洞形状影响又考虑空洞之间相互作用的场方程,并使之能够处理空洞体积比较大的弹塑性损伤问题· 相似文献
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Phase-field models have become popular to simulate cohesive failure problems because of their capability of predicting crack initiation and propagation without additional criteria. In this paper, a new phase-field damage model coupled with general softening laws for cohesive fracture is proposed based on the unified phase-field theory. The commonly used quadratic geometric function in the classical phase-field model is implemented in the proposed model. The modified degradation function related to the failure strength and length scale is used to obtain the length scale insensitive model. Based on the analytical solution of a 1-D case, general softening laws in cohesive zone models can be considered. Parameters in the degradation function can be calibrated according to different softening curves and material properties. Numerical examples show that the results obtained by the proposed model have a good agreement with experimental results and the length scale has a negligible influence on the load-displacement curves in most cases, which cannot be observed in classical phase-field model. 相似文献
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Spatial contact problems for rough elastic bodies under elastoplastic deformations of the unevenness
B. A. Galanov 《Journal of Applied Mathematics and Mechanics》1984,48(6):750-757
On the basis of /1, 2/, a model is constructed for the contact between a rigid stamp and a rough body taking elastoplastic deformations of the unevenness into account. The contact model for rough bodies with elastic deformations of the unevenness is a special case. A classical approach utilizing boundary integral equations is applied in the mathematical formulation of the contact problem. Under quite general assumptions (for instance, the multiconnectedness of the contact domain desired), the uniqueness and existence of the solution are investigated. A method is developed to determine the contact pressure, the closure of the bodies, and also the contact area which consists of two parts in the general case, a zone of elastoplastic deformation of the unevenness and a zone of their elastic deformation. The efficiency of the method is shown in examples of new contact problems. The solution is represented in a convenient form for analysing the influence of the roughness. This is of considerable value for material testing by a contact method. A fairly complete survey of research on contact problems for rough bodies can be found in /1–4/. 相似文献
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A finite element-mathematical programming method for elastoplastic contact problems with friction 总被引:3,自引:0,他引:3
Changming Zhu 《Finite Elements in Analysis and Design》1995,20(4):273-282
Both the elastoplastic constitutive equations and the frictional contact conditions are described as a kind of linear complementarity condition. Then based on the principle of virtual work and the finite element discretization, a mathematical programming method is obtained for the solution of elastoplastic contact problems with friction. This work is an extension of our previous work on the elastic contact problem (Zhu and Jin, Comput. Struct. 52, pp. 149–155 (1994)) and elastoplasticity problem (Zhu and Jin, Appl. Math. Mech. 14, pp. 635–642 (1993)). Two examples are chosen to illustrate the applicability of the method. 相似文献
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The problem on the elastoplastic transverse bending of Kirchhoff plates of variable thickness reinforced with fibers of constant cross section is formulated and its qualitative analysis is performed. An analytical solution to the problem is constructed in the case of cylindrical bending, and, by using the Bubnov-Galerkin method, an approximate solution for a rectangular plate is obtained. Based on calculations of plates reinforced with boron fibers and steel wire, it is shown that the load-carrying capacity of the structural member in elastoplastic bending is several times (or even by an order of magnitude) higher than in purely elastic one.Translated from Mekhanika Kompozitnykh Materialov, Vol. 41, No. 1, pp. 17–36, January–February, 2005. 相似文献
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为研究摩擦接触问题,本文建立了一个具有二类独立交量的二维弹塑性梁模型。由此提出了一个新的非线性二次互补性问题。其中的外部互补性条件定义了自由边界;而内部互补性条件则控制了弹塑性分界面。文中证明了此二次互补性问题等价于一非线性变分不等式,并导出了其对偶变分不等式。本文结果显示对偶问题较原问题有更多的优越性。应用于塑性极限分析理论中,文中最后证明了一个简单的下限定理。 相似文献