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Micromechanical Analysis of In-Plane Constraint Effect on Local Fracture Behavior of Cracks in the Weakest Locations of Dissimilar Metal Welded JointJie YangSchool of Energy and Power Engineering, University of Shanghai for Science and Technology摘 要:In this work, a set of GTN(Gurson–Tvergaard–Needleman) parameters of the Alloy52 M dissimilar metal......
on the mechanical properties of porous materials, a feasible method used frequently is based on the analysis of a simple representative void-cell model of the materials. In this aspect, GURSON[2] made... of the cell was equal to that of the aggregate. With this method a constitutive model for a cell containing a circular-cylindrical or spherical void was obtained. REUSCH et al[3] extended Gurson’s......
.TVERGAARD等[1]和NEEDLEMAN等[2]在GURSON[3]研究的基础上,考虑了孔洞的聚合和孔洞之间的相互作用,引入孔洞体积分数的概念对Gurson模型进行了进一步地修正,提出了目前应用最为广泛的GTN模型. GTN损伤模型参数众多,不同材料的GTN模型参数也不同.只有获得正确的GTN参数,才能获得这种材料孔洞演化的过程和损伤力学性能.ABBASSI等[4]通过有限元模拟和人工神经网络的方法标...体积分数来表征材料的损伤,并引入到材料屈服函数中,因此可以更好地预测材料在整个变形过程中的损伤行为. GURSON[3]首次提出的Gurson损伤模型是GTN损伤模型的前身,他第一次建立了孔洞演变规律和材料塑性势函数之间的关系,并将孔洞体积分数的概念引入到材料的屈服准则中,提出了包含材料孔洞体积分数的屈服函数: ......
of Mechanical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada; 4. FAW Car Co., Ltd., Changchun 130011, China Received 28 August 2012; accepted 25 October 2012 Abstract: The Gurson... damage models for materials with microvoids have been developed over the past few decades, starting with the works of McCLINTOCK [10], RICE and TRACEY [11] and GURSON [12]. Among them, Gurson-Tvergaard......
机理,建立合理的本构模型是首要的任务. 材料的韧性断裂属于细观损伤力学的范畴[5],QUAN等[6]采用Cockcroft-Latham损伤准则有效地预测量材料加热过程中发生断裂的位置及时刻.ZHANG等[7]通过Cockcroft-Latham损伤模型预测了镁合金板材轧制边发生断裂的条件,但是该模型忽略了空穴之间的交互作用.目前发展较为完善应用较为广泛的细观损伤模型GTN损伤模型是由GURSON[8]在1975提出,并由TVERGAARD等[9]相继完善的GTN (Gurson-Tvergaard-Needleman)模型.由于GTN模型存在不同的修正形式且模型参数为内变量,难以完全依靠实验获得全部模型参数.目前常用的获得该模型参数的方法是结合材料实验和有限元分析的反向优化法[10].王明正等[11]通过反向优化法获得了GTN损伤模型的参数,该模型可以有效预测钛合金塑性成形的过程.石柏军......
the exponential dependence of void growth-rate on the triaxiality ratio of remote stresses in a rigid-plastic material. GURSON[3] has investigated two different deformation modes of a representative volume..., 1969, 17: 201-217. [3] GURSON A L. Continuum theory of ductile rupture by void nucleation and growth: Part Ⅰ-Yield criteria and flow rules for porous ductile media[J]. J Eng Mater Tech, 1977, 99: 2-15......
实验相结合的方式确定AZ31镁合金的Gurson模型损伤参数并对镁合金板材温热冲压成形过程中的材料损伤演化行为进行了预测,但上述研究忽视不同温度对损伤参数的影响.因此,针对7075铝合金在不同温度成形过程中的损伤演化行为进行研究并实现仿真预测,将能实现对其成形性能更加准确的评价. 本文作者以7075-T6铝合金板材为研究对象,分析了其在不同温度下变形过程中的损伤演化规律,开展了铝合金板材在不同温度下的方盒拉深成形实验,结合响应曲面法和遗传优化算法确定了7075-T6铝合金GTN细观损伤特征参数,并进一步基于GTN损伤模型对7075-T6铝合金板材成形性能进行仿真研究,进一步结合实验对比损伤预测的准确性. 1 GTN损伤模型 GURSON[13]提出了有限大基体中含微孔洞的体胞模型并推导出多孔延性损伤模型,之后由TVERGARRD等[14]和NEEDLEMAN等[15]对其进行修......
model based on Fleck model which was appropriate in the high porosity stage. Gurson[13] model was usually used in the low porosity stage. In the transition stage, Redanz et al[14, 15] developed a linear combination of Fleck and Gurson model. Bocchini[16] analyzed the decrease of powder’s yield stress in warm compaction quantitatively. Ariffin et al[17] developed a yield criterion considering......
based on FLECK model which was appropriate in the high porosity stage. GURSON model was usually used during the low porosity stage[10]. In the transition stage, REDANZ[11-14] developed a linear combination of Fleck and Gurson model. All these models mainly focused on cold powder compaction, while few studies had been focused on warm powder compaction. The aim of this paper is to achieve a good......
on the analysis of a simple representative void-cell model of the materials. In this aspect, GURSON[3] made a pioneering contribution. He assumed that the void-matrix aggregate of a porous ductile media could be represented with a rigid-plastic cell containing a single void, and the void volume fraction (porosity) f of the cell is equal to that of the aggregate. REUSCH et al[4] extended GURSON model......
