Study on the damage constitutive model of rock considering the influence of dynamic ratio of tension to compression
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摘要: 岩石动态本构模型对理解动载下岩石的力学行为和解决岩石动力学问题具有重要作用。基于连续介质损伤力学,建立了一个弹塑性损伤耦合的岩石动态本构模型。该模型以统一强度理论作为屈服准则,并引入动态拉压比充分反映应变率效应;采用有效塑性应变和体积塑性应变表示压损伤变量和用有效塑性应变表示拉损伤变量从而反映拉压条件下岩石不同的损伤演化规律;采用分段函数来刻画岩石拉压条件下的不同塑性硬化行为;基于Fortran语言和LS-DYNA用户材料自定义接口(Umat)对所建立的本构模型进行数值实现;通过岩石单轴和三轴压缩试验、岩石单轴拉伸试验和岩石弹道试验等三个经典算例对所建立的本构模型展开验证,结果表明,该本构模型能全面刻画岩石的动静态力学行为。
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关键词:
Abstract: The dynamic constitutive model of rocks plays an important role in understanding the mechanical behavior of rocks under dynamic loads and solving rock dynamics problems. A dynamic constitutive model of rock with elastoplastic damage coupling based on continuum damage mechanics was established. This model uses the unified strength theory as the yield criterion and introduces a dynamic ratio of tension to compression to fully reflect the strain rate effect. The compressive damage variable is expressed with effective plastic strain and volumetric plastic strain, and the tensile damage variable with effective plastic strain to reflect the different damage evolution laws of rocks under tensile and compressive conditions. Using piecewise functions to characterize different plastic hardening behaviors of rocks under tensile and compressive conditions. The established constitutive model is numerically implemented of based on Fortran language and LS-DYNA user material customization interface (Umat). The established constitutive model is validated through three classic examples, namely, uniaxial and triaxial compression tests, uniaxial tensile tests, and ballistic tests on rocks. The results indicate that the constitutive model can comprehensively characterize the dynamic and static mechanical behavior of rocks.-
Key words:
- constitutive model /
- damage /
- ratio of tension to compression /
- strain rate /
- numerical simulation
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