【摘要】：基于林位錯強化的晶體塑性有限元模型物理意義清晰簡潔,具有廣泛的應(yīng)用。然而,只考慮林位錯強化的模型忽略了共面位錯之間的相互作用,導致模擬結(jié)果常常出現(xiàn)異常的扭曲失穩(wěn)現(xiàn)象。針對以上問題,通過分析位錯之間的相互作用,在林位錯強化模型中引入自硬化作用對模型進行改進。對改進前后兩個模型模擬單晶體沿單個和多個方向拉伸的變形模式以及冷軋鋁板剪切帶的形成特征進行了比較。結(jié)果顯示,對于單晶單滑移,兩個模型的穩(wěn)定性表現(xiàn)一致;但是對于單晶多滑移,改進前的模型出現(xiàn)了扭曲失穩(wěn),而引入自硬化的改進模型對于多滑移系的模擬符合真實情況,并改善了模型的穩(wěn)定性問題。對于冷軋鋁板發(fā)生剪切變形時剪切帶的形成特征,林位錯強化模型的不穩(wěn)定性放大了材料的失穩(wěn)變形,模型的低穩(wěn)定性和材料的變形失穩(wěn)疊加,導致預測的結(jié)果失穩(wěn)程度過高;而引入自硬化作用的改進模型改善了穩(wěn)定性問題,可以真實地反映材料本身的失穩(wěn)。
[Abstract]:The crystal plastic finite element model based on forest dislocation strengthening has a clear and concise physical meaning and is widely used. However, the model only considering forest dislocation strengthening ignores the interaction between coplanar dislocations, resulting in abnormal distortion and instability of simulation results. In view of the above problems, the self-hardening effect is introduced into the forest dislocation strengthening model to improve the model by analyzing the interaction between dislocations. The deformation modes of single crystal drawing along single and multiple directions and the formation characteristics of cold rolled aluminum sheet shear strip were compared before and after the modified two models were used to simulate the deformation of single crystal in single and multiple directions. The results show that the stability of the two models is the same for single crystal slip. However, for single-crystal multi-slip, the improved model is distorted and unstable, and the self-hardening model is introduced to simulate the multi-slip system in accordance with the real situation, and the stability of the model is improved. For the formation characteristics of shear band during shear deformation of cold rolled aluminum sheet, the instability of the forest dislocation strengthening model magnifies the instability deformation of the material, the low stability of the model and the superposition of the deformation instability of the material lead to the instability degree of the predicted result being too high. An improved self-hardening model is introduced to improve the stability problem, which can truly reflect the instability of the material itself.
【作者單位】： 上海交通大學材料科學與工程學院;
【基金】：國家自然科學基金資助項目(22451471107E0108)
【分類號】：TG111.2

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