| 基于微孔贯通细观损伤模型的金属韧性断裂分析 |
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| 引用本文： | 姜薇, 李亚智, 束一秀, 樊振兴. 基于微孔贯通细观损伤模型的金属韧性断裂分析[J]. 工程力学, 2014, 31(10): 27-32. DOI: 10.6052/j.issn.1000-4750.2013.04.0351 |
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| 作者姓名： | 姜薇 李亚智 束一秀 樊振兴 |
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| 作者单位： | 西北工业大学航空学院,西安 710000 |
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| 基金项目： | 国家自然科学基金项目(11272259,11002104) |
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| 摘 要： | 韧性材料断裂过程通常可看作是材料内部微孔洞的形核、扩展及相互贯通的积累。经典的Gurson- Tvergaard (GT)模型能够很好地模拟具有变形均匀、各向同性的孔洞的萌生及扩展过程;但无法模拟由孔洞贯通而引起的局部变形过程,因此需要对其修正,引入相应的孔洞贯通准则。该文采用两种贯通准则对经典GT模型进行修正,即Thomason的塑性极限载荷准则和临界等效塑性应变准则。借助用户自定义程序UMAT将采用这两种贯通准则修正的GT本构关系嵌入至商用有限元软件ABAQUS中,从而可通过对金属材料应力状态和断裂机理的分析控制孔洞的贯通。以一组含有不同缺口根半径的圆棒拉伸试验件为例,分析了该类金属构件自孔洞萌生至最终断裂的整个损伤演化过程,并与试验数据进行了对比,验证了该模型的有效性。该文还讨论了金属断裂过程中应力三轴度对微裂纹萌生与扩展的影响。
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| 关 键 词： | 韧性断裂 细观损伤模型 孔洞贯通 损伤准则 应力三轴度 |
| 收稿时间： | 2013-04-18 |
| 修稿时间： | 2013-06-13 |
INVESTIGATION OF METALLIC DUCTILE FRACTURE BY VOID-BASED MESO-DAMAGE MODEL |
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| JIANG Wei, LI Ya-zhi, SHU Yi-xiu, FAN Zhen-xing. INVESTIGATION OF METALLIC DUCTILE FRACTURE BY VOID-BASED MESO-DAMAGE MODEL[J]. Engineering Mechanics, 2014, 31(10): 27-32. DOI: 10.6052/j.issn.1000-4750.2013.04.0351 |
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| Authors: | JIANG Wei LI Ya-zhi SHU Yi-xiu FAN Zhen-xing |
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| Affiliation: | School of Aeronautics, Northwestern Polytechnical University, Xi’an 710000, China |
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| Abstract: | The ductile fracture of metallic materials is usually the result of void nucleation, growth and coalescence. The classical Gurson-Tvergaard (GT) model has proven to be an effective means for simulating the nucleation and growth of voids with homogenous deformations. However, as for the localized deformation due to the void coalescence, the GT model is limited. The original GT damage model is extended to the problem of localized deformations by incorporating two different void coalescence criteria in the paper. One is based on the plastic-limit-load model proposed by Thomason; the other assumes the onset of void coalescence using a critical equivalent plastic strain as a power law of stress triaxiality (defined by the ratio of the hydrostatic stress to the equivalent stress). Hence, void coalescence can be controlled by physical mechanisms, rather than by a critical void volume fraction which cannot be taken as a constant. The extended constitutive models are implemented into an implicit finite element code via a user defined material subroutine (UMAT) in ABAQUS. The void-based meso-damage model was adopted to study the ductile fracture of a series of notched round tensile bars. It is shown that the predictions of the fracture behavior from void nucleation to final material failure have a good agreement with the experiment data, which validates the proposed model. Also, the effects of stress triaxiality on the nucleation and propagation of microcracks are discussed. |
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| Keywords: | ductile failure meso-damage model void coalescence failure criterion stress triaxiality |
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