作者: Jun Wang, Zhi Ming Hao, Ping An Shi, Shao Rong Yu, Wei Fen Li

摘要: A three-phase constitutive model for TiNiNb shape memory alloys (SMAs) is proposed based on the fact that TiNiNb SMAs are dynamically composed of austenite, martensite and -Nb phases. In the considered ranges of stress and temperature, the behaviors of austenite, martensite and -Nb phases are assumed to be elastoplastic, and the behavior of an SMA is regarded as the dynamic combination of the individual behavior of each phase. Then a macroscopic constitutive description for TiNiNb SMAs is obtained by the conventional theory of plasticity, the theory of mixture, the theory of inclusion, and the description of phase transition by Tanaka. The method for determination of the material parameters is given. This constitutive model can describe the main characteristics of SMAs, such as ferrcelasticity, pseudoelasticity and shape memory effect.

2453

作者: Wei Xie, Ming Xiao Jia

摘要: A dynamic elastic-plastic microplane constitutive model for concrete based on M2 which is proposed by B.P. Bazant etc., is presented in this paper. The state of each microplane is characterized by normal deviatoric and volumetric strains and shear strain.The strain-stress relations for deviatoric and shear component is described as elastic-plastic model. A new concept: failure strain has been introduced. The stress shall be zero after the microplane stress reaches failure stain level. The reinforced effect of steel fiber on concrete is taken account in this paper. Finally 2 calculation examples have been adopted to verify the rationality and correctness of the proposed module.

421

作者: Martina Lovrenić-Jugović, Zdenko Tonković, Ivica Skozrit

摘要: A new one-dimensional constitutive model for human cortical bone is proposed to simulate the viscoelastic–viscoplastic behaviour occurring during creep-recovery tests.* *The material parameters are determined by fitting experimental results of creep-recovery tests reported in the published literature. *An *efficient computational *algorithm* for the integration of the proposed constitutive model at the material point level is derived. The derived algorithm in conjunction with the Jacobian matrix is implemented in the finite element code ABAQUS. The model predictions are found to be in good agreement with the experimental data presented in literature.

186

作者: Takaei Yamamoto, Akihiko Suzuki, Hiroki Cho, Toshio Sakuma

摘要: The transformation behavior of shape memory alloys is simulated for complex loadings of stress, strain and temperature. Calculations are made by using the “Accommodation Model” which is a constitutive model for shape memory alloys considering the accommodation behavior of the transformation strain. Calculated results are presented for the transformation behavior in the axial and shear stress state. These results are compared with those obtained by the experiment where tube specimens of the Ti-Ni shape memory alloy are subjected to the axial and torsion loading. The proposed constitutive model can predict the transformation behavior including the plastic strain effect of polycrystalline Ti-Ni shape memory alloys under non-proportional multiaxial loading condition.

46

作者: Shuang Wu, Shou Gen Zhao, Da Fang Wu, Xue Mei Yu

摘要: The methods of constitutive modeling of restrained recovery for Shape memory alloys (SMAs) were described in this paper and experiments were carried out to provide the essential data for the methods. The present mathematical constitutive models are inconvenient for engineering applications. Then a back propagation (BP) neural network model was developed for restrained recovery of SMAs. This BP neural network model can learn the hysteresis of SMAs in the process of heating and cooling based on its properties of nonlinear function mapping and adaptation, and it can predict the complete restrained recovery stress of SMAs with different initial strains. The predicted results obtained from the proposed BP model agree well with the experimental data. Moreover, the proposed BP model is more simple, convenient and low cost compared with the present mathematical constitutive models.

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