科研成果 by Type: Conference Paper

A thermal-elastoplastic constitutive model is proposed for particle-filled composites in this paper. Particles are assumed to be linear thermoelastic while the matrix follows the thermal-elastoplastic responses with the generalized Ramberg-Osgood relation. Based on the micromechanics methodology and homogenization procedures, the effective thermal-mechanical constitutive functions are derived including the macroscopic Helmholtz free energy and the macroscopic yield function.First, it is assumed that in the case of plastic unloading or stress-strain state being in the macroscopic yield surface, the constitutive relation of the composites is linear thermoelastic expressed by the macroscopic Helmholtz free energy. The micromechanics-based thermoelastic properties of the composite are obtained including the effective elastic moduli, thermal expansion coefficients, and specific heats.Furthermore, with the concept of linear comparison composites, the variational principle is extended to consider the thermal effect, from which the lower bound of the macroscopic stress potential for the nonlinear composites can be computed. The associated macroscopic plastic strain is defined, and the macroscopic yield function in the temperature-strain space is therefore determined.Finally, the above two constitutive functions are combined with the thermal-elastoplastic constitutive theory proposed by Huang (1994) to develop the loading-unloading criterion in the temperature-strain space and the incremental thermal-elastoplastic constitutive relations for particulate composites. The results can be useful in the study of the thermomechanical behavior of particle-filled composites at elevated temperatures.

An asymmetric single-nanoslit with lateral dimension of only 370 nm is demonstrated to work as an efficient SPP unidirectional generator at wavelength of 830 nm.

中国土地制度改革一直是社会关注的焦点。在部分地方政府债务风险暴露后,农村土地制度改革更是事关地方政府的"土地财政"和"土地金融"行为。李力行教授代表国发院土地制度改革综合课题组,借助成都土地改革的最新进展,说明土地制度改革可能是解决政府主导经济、地方政府深陷于债务问题的根本出路。