为探索由月球表面特殊光热环境导致的驻人月球科研站围护结构传热过程与地球建筑的差异性,基于月球表面太阳辐射模型,根据有限差分法建立围护结构的传热模型,对影响内表面温度的物性参数、朝向等因素进行模拟分析。结果表明:当防热层、...为探索由月球表面特殊光热环境导致的驻人月球科研站围护结构传热过程与地球建筑的差异性,基于月球表面太阳辐射模型,根据有限差分法建立围护结构的传热模型,对影响内表面温度的物性参数、朝向等因素进行模拟分析。结果表明:当防热层、隔热层和阻气层分别取20 mm Nextel BF-20、240 mm Pyrogel 6650、20 mm Kapton时,水平屋顶内表面温度的波动范围为16.8~22.4℃;厚度和导热系数是影响围护结构传热性能最重要的因素,综合考虑建造成本与隔热性能,应尽量降低围护结构的厚度与导热系数,采用低密度、高比热的材料;内表面的对流换热系数与外表面的发射率直接影响围护结构的边界换热量,可结合不同朝向的辐射特点与热舒适要求,个性化定制具有差异化热惰性和外表面发射率的材料。展开更多
The auto-parametric resonance of a continuous-beam bridge model subjected to a two-point periodic excitation is experimentally and numerically investigated in this study.An auto-parametric resonance experiment of the ...The auto-parametric resonance of a continuous-beam bridge model subjected to a two-point periodic excitation is experimentally and numerically investigated in this study.An auto-parametric resonance experiment of the test model is conducted to observe and measure the auto-parametric resonance of a continuous beam under a two-point excitation on columns.The parametric vibration equation is established for the test model using the finite-element method.The auto-parametric resonance stability of the structure is analyzed by using Newmark's method and the energy-growth exponent method.The effects of the phase difference of the two-point excitation on the stability boundaries of auto-parametric resonance are studied for the test model.Compared with the experiment,the numerical instability predictions of auto-parametric resonance are consistent with the test phenomena,and the numerical stability boundaries of auto-parametric resonance agree with the experimental ones.For a continuous beam bridge,when the ratio of multipoint excitation frequency(applied to the columns)to natural frequency of the continuous girder is approximately equal to 2,the continuous beam may undergo a strong auto-parametric resonance.Combined with the present experiment and analysis,a hypothesis of Volgograd Bridge's serpentine vibration is discussed.展开更多
文摘为探索由月球表面特殊光热环境导致的驻人月球科研站围护结构传热过程与地球建筑的差异性,基于月球表面太阳辐射模型,根据有限差分法建立围护结构的传热模型,对影响内表面温度的物性参数、朝向等因素进行模拟分析。结果表明:当防热层、隔热层和阻气层分别取20 mm Nextel BF-20、240 mm Pyrogel 6650、20 mm Kapton时,水平屋顶内表面温度的波动范围为16.8~22.4℃;厚度和导热系数是影响围护结构传热性能最重要的因素,综合考虑建造成本与隔热性能,应尽量降低围护结构的厚度与导热系数,采用低密度、高比热的材料;内表面的对流换热系数与外表面的发射率直接影响围护结构的边界换热量,可结合不同朝向的辐射特点与热舒适要求,个性化定制具有差异化热惰性和外表面发射率的材料。
基金National Natural Science Foundation of China under Grant No.51879191。
文摘The auto-parametric resonance of a continuous-beam bridge model subjected to a two-point periodic excitation is experimentally and numerically investigated in this study.An auto-parametric resonance experiment of the test model is conducted to observe and measure the auto-parametric resonance of a continuous beam under a two-point excitation on columns.The parametric vibration equation is established for the test model using the finite-element method.The auto-parametric resonance stability of the structure is analyzed by using Newmark's method and the energy-growth exponent method.The effects of the phase difference of the two-point excitation on the stability boundaries of auto-parametric resonance are studied for the test model.Compared with the experiment,the numerical instability predictions of auto-parametric resonance are consistent with the test phenomena,and the numerical stability boundaries of auto-parametric resonance agree with the experimental ones.For a continuous beam bridge,when the ratio of multipoint excitation frequency(applied to the columns)to natural frequency of the continuous girder is approximately equal to 2,the continuous beam may undergo a strong auto-parametric resonance.Combined with the present experiment and analysis,a hypothesis of Volgograd Bridge's serpentine vibration is discussed.
