In order to more accurately calculate the fatigue damage and fatigue life of steel-concrete composite beam under standard vehicle load,the steel beam components of a large-span steel-concrete composite beam suspension...In order to more accurately calculate the fatigue damage and fatigue life of steel-concrete composite beam under standard vehicle load,the steel beam components of a large-span steel-concrete composite beam suspension bridge were taken as the research object.Based on the S-N curve and linear fatigue damage theory,a standard segment model was established.Accordingly,the welding position of the secondary longitudinal beam was identified as the focus fatigue point,and the stress time course calculation was done for the point.The results showed that when the vehicle mass increases from 50 t to 100 t,the amount of fatigue damage will increase by more than 5 times in the same period of time,and the increase in the vehicle mass will reduce the fatigue life of the bridge structure.The fatigue damage of bridge structures increases with the increase of vehicle speed.The increase rate of fatigue damage is greater at low speeds,and the increase rate of fatigue damage slows down at high speeds.展开更多
黄土的热参数是黄土灾害成因机制研究及热工计算中的重要指标,而含水率和干密度对黄土的热参数具有一定的影响。对不同含水率、不同干密度黄土试样,采用Test Protocol Hot Disk TPS 2500S型热常数分析仪,在常温下开展热参数试验,探讨黄...黄土的热参数是黄土灾害成因机制研究及热工计算中的重要指标,而含水率和干密度对黄土的热参数具有一定的影响。对不同含水率、不同干密度黄土试样,采用Test Protocol Hot Disk TPS 2500S型热常数分析仪,在常温下开展热参数试验,探讨黄土热参数随含水率及干密度的变化规律。研究结果表明:黄土试样含水率一定时,干密度越大,其导热系数、比热容及热扩散系数也越大;黄土试样的导热系数和比热容随含水率的增大基本呈线性规律增大;当含水率较低时,热扩散系数随含水率的增大而增大;当达到一定含水率时,热扩散系数随含水率的增大而减小;继续增大含水率,热扩散系数趋于稳定。含水率对黄土热参数的影响程度大于干密度对其热参数的影响程度。在热工计算中,可根据土体含水率和干密度动态地选择热参数。展开更多
文摘In order to more accurately calculate the fatigue damage and fatigue life of steel-concrete composite beam under standard vehicle load,the steel beam components of a large-span steel-concrete composite beam suspension bridge were taken as the research object.Based on the S-N curve and linear fatigue damage theory,a standard segment model was established.Accordingly,the welding position of the secondary longitudinal beam was identified as the focus fatigue point,and the stress time course calculation was done for the point.The results showed that when the vehicle mass increases from 50 t to 100 t,the amount of fatigue damage will increase by more than 5 times in the same period of time,and the increase in the vehicle mass will reduce the fatigue life of the bridge structure.The fatigue damage of bridge structures increases with the increase of vehicle speed.The increase rate of fatigue damage is greater at low speeds,and the increase rate of fatigue damage slows down at high speeds.
文摘黄土的热参数是黄土灾害成因机制研究及热工计算中的重要指标,而含水率和干密度对黄土的热参数具有一定的影响。对不同含水率、不同干密度黄土试样,采用Test Protocol Hot Disk TPS 2500S型热常数分析仪,在常温下开展热参数试验,探讨黄土热参数随含水率及干密度的变化规律。研究结果表明:黄土试样含水率一定时,干密度越大,其导热系数、比热容及热扩散系数也越大;黄土试样的导热系数和比热容随含水率的增大基本呈线性规律增大;当含水率较低时,热扩散系数随含水率的增大而增大;当达到一定含水率时,热扩散系数随含水率的增大而减小;继续增大含水率,热扩散系数趋于稳定。含水率对黄土热参数的影响程度大于干密度对其热参数的影响程度。在热工计算中,可根据土体含水率和干密度动态地选择热参数。
