Under an applied voltage, dielectric elastomers （DEs） produce an actuation strain that is nonlinear, partly because of the material properties. In this study, an experimental characterization is conducted to evaluat...Under an applied voltage, dielectric elastomers （DEs） produce an actuation strain that is nonlinear, partly because of the material properties. In this study, an experimental characterization is conducted to evaluate how the ambient temperature and pre-stretch affected the actuation performance. For DEs with a pre-stretch of 2 × 2, an increase of temperature from -10° to 80° results in a variation in the actuation strain of more than 1700%. Low pre-stretched DEs are more susceptible to temperature change; while highly pre-stretched DEs are relatively insensitive to temperature, because in this case the energy conversion was dominated by mechanical stretching, rather than thermal conduction, during the actuation.展开更多
To explore the temperature dependence of deformation behavior of BCC structural materials and the relevant effect of pre-annealing, commercially pure iron （CP Fe） produced by equal-channel angular pressing （ECAP） ...To explore the temperature dependence of deformation behavior of BCC structural materials and the relevant effect of pre-annealing, commercially pure iron （CP Fe） produced by equal-channel angular pressing （ECAP） is selected as the experimental material. The influences of deformation temperature T and pre-annealing on deformation behavior, surface deformation characteristics and substructures of ECAP Fe were systematically studied. The results show that ECAP Fe undergoes a remarkable strain softening stage after a rapid strain hardening during uniaxial compression, and the softening degree and the yield strength avs first decrease and then increase with raising temperature. Pre-annealing at 400 ℃ effectively weakens the strain softening degree and increases trys. To understand the influence of deformation temperature on deformation behavior, as well as the relevant pre-annealing effect, deformation and damage characteristics and dislocation structures are studied in detail. In a word, the strain softening of ECAP Fe is associated not only with internal structural instability, but also with temperature, and pre-annealing at 400 ℃ improves high-temperature me- chanical properties of ECAP Fe.展开更多
基金supported by the Major Program of National Natural Science Foundation of China(51290294)the Doctoral Fund of Ministry of Education of China(20120201110030)
文摘Under an applied voltage, dielectric elastomers （DEs） produce an actuation strain that is nonlinear, partly because of the material properties. In this study, an experimental characterization is conducted to evaluate how the ambient temperature and pre-stretch affected the actuation performance. For DEs with a pre-stretch of 2 × 2, an increase of temperature from -10° to 80° results in a variation in the actuation strain of more than 1700%. Low pre-stretched DEs are more susceptible to temperature change; while highly pre-stretched DEs are relatively insensitive to temperature, because in this case the energy conversion was dominated by mechanical stretching, rather than thermal conduction, during the actuation.
基金financially supported by the National Natural Science Foundation of China (Nos. 51231002, 51271054, 51201077 and 50671023)the Specialized Research Fund for the Doctoral Program of Higher Education of China (No. 20110042110017)the Fundamental Research Funds for the Central Universities of China (Nos. N110105001 and N120505001)
文摘To explore the temperature dependence of deformation behavior of BCC structural materials and the relevant effect of pre-annealing, commercially pure iron （CP Fe） produced by equal-channel angular pressing （ECAP） is selected as the experimental material. The influences of deformation temperature T and pre-annealing on deformation behavior, surface deformation characteristics and substructures of ECAP Fe were systematically studied. The results show that ECAP Fe undergoes a remarkable strain softening stage after a rapid strain hardening during uniaxial compression, and the softening degree and the yield strength avs first decrease and then increase with raising temperature. Pre-annealing at 400 ℃ effectively weakens the strain softening degree and increases trys. To understand the influence of deformation temperature on deformation behavior, as well as the relevant pre-annealing effect, deformation and damage characteristics and dislocation structures are studied in detail. In a word, the strain softening of ECAP Fe is associated not only with internal structural instability, but also with temperature, and pre-annealing at 400 ℃ improves high-temperature me- chanical properties of ECAP Fe.
