共查询到16条相似文献,搜索用时 31 毫秒
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梯度增强的弹塑性损伤非局部本构模型研究 总被引:3,自引:0,他引:3
简要介绍了几种主要的梯度增强非局部模型.基于“能量耗散梯度依赖”原则,在连续介质热力学框架内推导了梯度增强损伤与塑性耦合的本构关系,同时给出了一个基于塑性的损伤模型的梯度依赖本构的具体形式.在数值计算方面,结合移动最小二乘法和泰勒级数展开方法,建立了损伤场(有限元高斯积分点上)的Laplace值的近似求解格式,分别给出了二维和三维情况下的相关公式.给出的二维的韧性断裂的梯度依赖损伤塑性的数值应用,表明了格式的有效性和实用性.还讨论了内部长度的意义及取值问题. 相似文献
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梯度弹性理论在描述材料微结构起主导作用的力学行为时具有显著优势,将其与损伤理论相结合,可在材料破坏研究中考虑微结构的影响.基于修正梯度弹性理论,将应变张量、应变梯度张量和损伤变量作为Helmholtz自由能函数的状态变量,并在自然状态附近对自由能函数作Taylor展开,进而由热力学基本定律,推导出修正梯度弹性损伤理论本构方程的一般形式.编制有限元程序,模拟土样损伤局部化带的发展演化过程.结果表明,修正梯度弹性损伤理论消除了网格依赖性;损伤局部化带不是与损伤同时发生,而是在损伤发展到一定程度后再逐渐显现出来. 相似文献
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一般各向异性复合材料层板基体损伤性能衰减研究(Ⅰ)——分解刚 … 总被引:1,自引:1,他引:0
本文尝试将损伤复合材料层板性能衰减研究扩展到含一般各向异性铺层的基体开裂层板,在第一部分中,采用分解刚度法处理法向与剪切响应的耦合问题,对承受面内载荷的对称约束开裂层板,导出本构关系的近似解析解,将层板有效刚度表为裂纹密度的函数。 相似文献
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Stephan Wulfinghoff Atefeh Alipour Shahed Rezaei Julian Kochmann Stefanie Reese 《PAMM》2016,16(1):411-412
Gradient plasticity can account for experimentally observed size effects. Here, a previously developed gradient plasticity model is extended to account for interface delamination processes. The crystal plasticity model is based on the gradient of an equivalent plastic strain measure. A modification of the related boundary conditions allows for the formulation of a generalized cohezive zone model which can take into account the effect of interface delamination on the gradient plasticity solution. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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一阶模糊谓词逻辑公式的解释模型真度理论及其应用 总被引:5,自引:0,他引:5
基于一阶模糊谓词逻辑公式的有限和可数解释真度的理论,引入了一阶模糊谓词逻辑公式的解释模型及解释模型真度的概念,并讨论了它们的一系列性质及其在近似推理中的应用. 相似文献
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D. Schütz 《K-Theory》2002,25(1):59-97
We use the one-parameter fixed-point theory of Geoghegan and Nicas to get information about the closed orbit structure of transverse gradient flows of closed 1-forms on a closed manifold M. We define a noncommutative zeta function in an object related to the first Hochschild homology group of the Novikov ring associated to the 1-form and relate it to the torsion of a natural chain homotopy equivalence between the Novikov complex and a completed simplicial chain complex of the universal cover of M. 相似文献
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A simple phase-field model for first-order phase transitions with hysteresis is proposed. It describes both temperature- and stress-induced transitions between austenitic and (oriented) martensitic regimes in a shape memory alloy (SMA). Finally, numerical simulations of local paths of the system are performed in the (ε,σ) and (ε,θ) planes, respectively, when either stress or temperature cyclic processes are considered and phase diffusion is neglected. 相似文献
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We present a partial first-order affine-scaling method for solving smooth optimization with linear inequality constraints. At each iteration, the algorithm considers a subset of the constraints to reduce the complexity. We prove the global convergence of the algorithm for general smooth objective functions, and show it converges at sublinear rate when the objective function is quadratic. Numerical experiments indicate that our algorithm is efficient. 相似文献