铝电解阴极炭块破裂过程的渗透-应力-损伤耦合效应

The aluminum industry has been plagued by the problem of the shorter cell life, in which, the case that the cathode carbon block failed in advance is not uncommon due to short of the prediction and control of the failure process of the core parts, the cathode carbon block. It has become the main bottleneck to prolong the cell life. Based on the specific serving environment of the cathode carbon block, the characteristics of penetration coupled by stress and damage in the failure process of cathode block in aluminum electrolysis is studied employing meso-damage mechanics and multi field coupling theory and the basic scientific research on the evolution law of the cathode carbon block's functioning property is carried out. The specific research idea is to construct a set of experimental technology and test analytical method on the penetration coupling of the whole stress-strain process based on observation of the cathode block under the aluminum electrolysis, to analyze the effect of the penetration evolution induced by microstructure characteristics change of the carbon block on the macroscopic mechanical and study the failure mechanism of the carbon block under the coupling function of the penetration-stress; to construct the mesoscopic damage constitutive equation of the carbon block and the coupling model of penetration-stress-damage. And the new constructed model is conducted by the finite element transplant to realize the numerical simulation of the penetration damage evolution process of the carbon block, which is used to predict the space-time evolution law of penetration field, stress field and damage field, to provide technique parameters and theoretical basis for the optimized design of aluminum electrolysis cell and the cell life prolonging and prediction. It has important theoretical and practical value.

铝电解槽寿命偏短一直是困扰铝业界的难题，其中，由于缺乏对核心构件阴极炭块破损过程的预测与控制，导致其先行失效的例子屡见不鲜，成为制约延长槽寿命的主要瓶颈。针对阴极炭块所处的特定服役环境，本项目拟用细观损伤力学和多场耦合理论来研究铝电解下阴极炭块破裂过程的渗透-应力-损伤耦合效应，对阴极炭块工作性态的时空演化规律进行基础研究。具体研究思路是，构建出一套基于CT观测的铝电解环境下阴极炭块应力-应变全过程渗透耦合试验技术与测试分析方法，分析炭块破裂过程中不同应力-应变阶段渗透率的演化规律，建立炭块渗透-应力耦合方程，并结合新建立的炭块细观损伤本构方程，建立阴极炭块破裂过程的渗透-应力-损伤耦合模型；并对新构模型进行有限元移植，实现炭块渗透损伤演化过程的数值模拟，用于预测渗流场、应力场和损伤场的时空演化规律，从而为铝电解槽的优化设计及延长和预测槽寿命提供技术参数和理论依据，具有重要理论和实用价值。

由于缺乏对核心构件阴极炭块破损过程的预测与控制，在大量铝电解槽早期破损事故中，阴极炭块先行失效的例子屡见不鲜，成为制约延长槽寿命的主要瓶颈。因此作为槽中最薄弱的环节，阴极炭块已成为铝电解槽中最关键的结构元件之一，日益被铝电解界所关注。如何能够准确地预测铝电解过程中阴极炭块工作性态的时空演化规律，保证其结构的完整性和安全可靠地服役对电解槽的正常运行是至关重要的，是铝电解槽优化设计和操作管理所面临的共同问题。. 针对阴极炭块所处的特定服役环境，本项目构建出了一套基于CT观测的铝电解环境下阴极炭块应力—应变全过程渗透耦合试验技术与测试分析方法，从细观角度揭示了铝电解阴极炭块破裂过程中渗透—应力—损伤耦合效应的时空演化规律及其机制；结果表明阴极炭块所受应力在达到其强度前，其渗透系数随着外载荷增大而减少，阴极炭块中钠渗透含量越高，产生钠膨胀应变越大，对于其蠕变力学性能影响越显著，阴极炭块中骨料的形状、级配和含量都会对钠渗透膨胀及力学性能产生影响，可为阴极炭块的生产和选用提供参考；在此基础上建立了渗透—应力—损伤耦合数值模型，并对新发展的耦合模型进行了有限元移植，实现了阴极炭块渗透损伤演化过程的数值模拟，可用于预测炭块中渗透场、应力场和损伤场的时空演化规律，从而能够为铝电解槽的优化设计以及延长和预测槽寿命提供技术参数和理论依据。

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