The theoretical characterizations on the triangular-form thixotropy-loop tests of an LDPE melt （PE-FSB- 23D022/Q200） were conducted in the present paper by using a new thixotropy model, which is constituted by the u...The theoretical characterizations on the triangular-form thixotropy-loop tests of an LDPE melt （PE-FSB- 23D022/Q200） were conducted in the present paper by using a new thixotropy model, which is constituted by the upper convected Maxwell model and a rate-type kinetic equation. The new thixotropic Maxwell model can partially describe well three reported thixotropy-loop experiments by comparison with the previous calculations of the variant form of the thixotropy-type Huang model. It is noted that the stress deviations between the experiments and the predictions of the new thixotropic Maxwell model are much slighter than those deviations obtained by using the variant Huang model at the same condition, although both models include five parameters. The constitution of the new thixotropic Maxwell model is more reasonable than that of the variant Huang model.展开更多
Ultra-high-temperature materials have applications in aerospace and nuclear industry.They are usually subjected to complex thermal environments during service.The mechanical properties of materials in ultra-high-tempe...Ultra-high-temperature materials have applications in aerospace and nuclear industry.They are usually subjected to complex thermal environments during service.The mechanical properties of materials in ultra-high-temperature environments have been attracted increasing attentions.However,the characterization and evaluation of ultra-high-temperature mechanical properties of materials are still challenging work.This article presents a review on the mechanical properties of materials at elevated temperatures.The experimental results and techniques on the ultra-high-temperature mechanical properties of materials are reviewed.The constitutive models of materials at elevated temperatures are discussed.The recent research progress on the quantitative theoretical characterization models for the temperature-dependent fracture strength of advanced ceramics and their composites is also given,and the emphasis is placed on the applications of the force-heat equivalence energy density principle.The thermal–mechanical-oxygen coupled computational mechanics of materials are discussed.Furthermore,the outlook and concluding remarks are highlighted.展开更多
基金This work was financially supported by the National Natural Science Foundation of China (No. 10402024).
文摘The theoretical characterizations on the triangular-form thixotropy-loop tests of an LDPE melt （PE-FSB- 23D022/Q200） were conducted in the present paper by using a new thixotropy model, which is constituted by the upper convected Maxwell model and a rate-type kinetic equation. The new thixotropic Maxwell model can partially describe well three reported thixotropy-loop experiments by comparison with the previous calculations of the variant form of the thixotropy-type Huang model. It is noted that the stress deviations between the experiments and the predictions of the new thixotropic Maxwell model are much slighter than those deviations obtained by using the variant Huang model at the same condition, although both models include five parameters. The constitution of the new thixotropic Maxwell model is more reasonable than that of the variant Huang model.
文摘Ultra-high-temperature materials have applications in aerospace and nuclear industry.They are usually subjected to complex thermal environments during service.The mechanical properties of materials in ultra-high-temperature environments have been attracted increasing attentions.However,the characterization and evaluation of ultra-high-temperature mechanical properties of materials are still challenging work.This article presents a review on the mechanical properties of materials at elevated temperatures.The experimental results and techniques on the ultra-high-temperature mechanical properties of materials are reviewed.The constitutive models of materials at elevated temperatures are discussed.The recent research progress on the quantitative theoretical characterization models for the temperature-dependent fracture strength of advanced ceramics and their composites is also given,and the emphasis is placed on the applications of the force-heat equivalence energy density principle.The thermal–mechanical-oxygen coupled computational mechanics of materials are discussed.Furthermore,the outlook and concluding remarks are highlighted.
