Papers by Keyword: Constitutive Relation

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Authors: Ze Yu Wu, Xin Li Bai, Bing Ma
Abstract: In finite element calculation of plastic mechanics, isotropic hardening model, kinematic hardening model and mixed hardening model have their advantages and disadvantages as well as applicability area. In this paper, by use of the tensor analysis method and mixed hardening theory in plastic mechanics, the constitutive relation of 3-D mixed hardening problem is derived in detail based on the plane mixed hardening. Numerical results show that, the proposed 3-D mixed hardening constitutive relation agrees well with the test results in existing references, and can be used in the 3-D elastic-plastic finite element analysis.
927
Authors: Chong Yang Gao, W.R. Lu
Abstract: In this paper, a constitutive description of the true stress-strain behaviors of nano-twinned metals has been proposed. The size effects of nano-scale twin boundaries (TBs) and ultra-fine grain boundaries (GBs) are considered in the athermal stress. The evolution of the dislocation density with strain under the influence of strain rate and temperature is introduced in the thermal stress based on our previous meso-scale constitutive model. The new model can effectively describe the strength transition regime in nano-twinned metals. The proposed model’s predictions of true stress-strain relation curves for nano-twinned copper are compared with the experimental results of uniaxial tension tests for validation. The comparisons show that the previous models in literature for the dependence of initial yield strength on twin spacing cannot describe the experimental data correctly when the twin spacing tends to zero; however, the phenomenological model proposed in this paper for the twin spacing depending relation is theoretically rational and can well describe the experimental data in the whole range of twin spacing.
109
Authors: W. Lu, Dai Ning Fang, Keh Chih Hwang
983
Authors: Xiao Qing Chen, Dai Ning Fang
977
Authors: L. Yu, Shou Wen Yu, Xi Qiao Feng
Abstract: In this paper, a phenomenological, nonlinear constitutive relation of ferroelectric ceramics is established by considering the fact that domain switching happens gradually with the external loading. A simplified gradual switching model is suggested and implemented into the constitutive law of ferroelectric materials. The volume fraction of domain switching is used as the internal variable in the model, and its evolution equation with mechanical/electrical loading is given. Comparison with experimental results shows that this simple constitutive model can predict the nonlinear hysteresis responses of ferroelectric materials.
813
Authors: Zhen Hai Wei, Meng Shu Wang, Ding Li Zhang
Abstract: The analysis of structural materials, especially the theoretical research, is always a challenge. Starting from the structural characteristics of the material, the theory of full state function about the strength - stiffness - strain that reflects the properties of structural material is established on the basis of the structural state of the material. The full state function is an important method to solve this problem. In order to further analyze the characteristics of the full state function, the full state function, strength theory of the material and the constitutive relation found are first studied. It is found that the full state function can more comprehensively reflect the properties of the structural material. The full state function accommodates the strength theory in the classical elastic-plastic theory. The full constitutive relation of the materials can be derived from the full state function. That is to say, the full state function can unify the strength theory and constitutive relation in the classical theory and can be used for the analysis of the structural materials. The full state function is more than a mere form, because it has explicit physical and mechanical meanings.
17
Authors: P.T. Moe, Yawar Abbas Khan, Henry Sigvart Valberg, Sigurd Støren
Abstract: The article presents an outline of a scientific approach for testing constitutive relations for the aluminum extrusion process. By comparing ram force, container friction, die face pressure, outlet temperature measurement during rod extrusion with corresponding simulated data, inferences can in principle be drawn with respect to the validity models. The paper indicates that simulation results from the 2D ALMA2π program are in fair agreement with measurements during extrusion of AA6060, but more work needs to be done to control thermal conditions during extrusion.
71
Authors: Jin Sheng He, She Liang Wang, Guang Yaun Weng
Abstract: In order to effectively use Magnetically Controlled Shape Memory Alloy (MSMA) for vibration control in civil engineering structure, the deformation mechanism and dynamic characteristics of the MSMA were studied; research methods apply to the constitutive relation of vibration control in civil engineering structure is given. Based on the study about MSMA vibration controller and its application in structural vibration control in engineering, MSMA in structure vibration control application prospect and development direction are introduced. At the same time, for the difficulties existing in the application are discussed in this paper. The results prove that MSMA materials in structural vibration control are of important value.
66
Authors: Quan Bin Zhao, Xin Liang Jiang
Abstract: The characteristics and research situation of bond-slip performance at the inter face of concrete and other materials are introduced, and the bond-slip constitutive relation models are summarized at the same time. Through the load-slip curves obtained from the pull-out experiment of CFFP, the proposed bond-slip constitutive relation models are presenting, including the simple one. With the numerical simulation analysis of CFFP is carried out by the use of the proposed constitutive relation, while the numerical simulation results are in good agreement with the experimental results conducted before, which is feasible and can be applied to further research on CFFP.
3133
Authors: Dong Mei Wang
Abstract: The investigation into the cushioning properties of multi-layer corrugated boards is a hotspot issue in the packaging field. People one after another investigate into the compressive properties based on experiments. As far as authors' knowledge is concerned, no theoretical research on compressive constitutive relation for multi-layer corrugated boards has ever been reported in literature. Therefore, we investigated into the compressive properties of multi-layer corrugated boards and analyzed their compressive breakage mechanism. The compression curve of multi-layer corrugated boards presents the three sections of linear elasticity, sub-buckling going with local collapse and densification. We constructed the compressive constitutive equation by a subsection function. The equation is standardized by the solid modulus Es of corrugated sandwich materials. Focusing on the structure characteristics, it can express the compression resistance and cushioning properties in the same curve for different basis materials. Comparison between the theory and experiments shows that a good consistency is achieved between theoretical and experimental stress-strain curves. By means of the compressive constitutive equation, the compression resistance and cushioning properties can be evaluated without more experiments, which facilitates the optimization of the structure of the corrugated sandwich structure and the optimized design of the cushioning package.
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