基于数值模拟基本假设,运用有效应力原理以及振动孔隙水压力增长经验模式,采用应力循环孔压增量计算方法,直接针对非自由可液化场地基地震反应的大型振动台试验建立数值计算模型,并据此进行可液化场地基孔压动力增长数值模拟。数值模拟...基于数值模拟基本假设,运用有效应力原理以及振动孔隙水压力增长经验模式,采用应力循环孔压增量计算方法,直接针对非自由可液化场地基地震反应的大型振动台试验建立数值计算模型,并据此进行可液化场地基孔压动力增长数值模拟。数值模拟结果表明:分别在0.15g和0.50g El Centro波输入下,孔压在13 s之前无明显变化,至13 s瞬时增长,20 s左右达到最大值,并且自下而上峰期孔压比逐步增大;其中0.5g El Centro波输入下整个土层达到全部液化的孔压比,而0.15g El Centro波输入下仅上部土层具有局部液化的孔压比。同时由数值模拟结果可发现:由于桩-土动力相互作用,致使近桩区孔压较远桩区孔压高且在桩周附近形成一定孔压梯度,但对孔压增长趋势无太大影响;数值模拟获得的地基振动孔隙水压力增长规律与试验记录基本保持一致。总的来讲,这种孔压动力增长的数值模拟方法,在强震输入下基本能够刻画土层中孔压的动力增长过程,而弱震输入下的计算误差较明显。展开更多
A fast hybrid algorithm based on gridless method coupled with finite volume method （FVM） is developed for the solution to Euler equations. Compared with pure gridless method, the efficiency of the hybrid algorithm i...A fast hybrid algorithm based on gridless method coupled with finite volume method （FVM） is developed for the solution to Euler equations. Compared with pure gridless method, the efficiency of the hybrid algorithm is improved to the level of finite volume method for most parts of the flow filed arc covered with grid cells. Moreover, the hybrid method is flexible to deal with the configurations as clouds of points are used to cover the region adjacent to the bodies. Mirror satellites and mirror grid cells arc introduced to the interface to accomplish data communication between the different parts of the flow field. The Euler Equations arc spatially discretized with finite volume method and gridless method in mesh and clouds of points respectively, and an explicit four-stage Runge-Kutta scheme is utilized to reach the steady-state solution. Internal flows in channels and external flows over airfoils arc investigated with hybrid method, and the solutions arc comparad to those using pure finite volume method and pure gridless method. Numerical examples show that the hybrid algorithm captures the shock waves accurately, and it is as efficient as fmite volume method.展开更多
文摘基于数值模拟基本假设,运用有效应力原理以及振动孔隙水压力增长经验模式,采用应力循环孔压增量计算方法,直接针对非自由可液化场地基地震反应的大型振动台试验建立数值计算模型,并据此进行可液化场地基孔压动力增长数值模拟。数值模拟结果表明:分别在0.15g和0.50g El Centro波输入下,孔压在13 s之前无明显变化,至13 s瞬时增长,20 s左右达到最大值,并且自下而上峰期孔压比逐步增大;其中0.5g El Centro波输入下整个土层达到全部液化的孔压比,而0.15g El Centro波输入下仅上部土层具有局部液化的孔压比。同时由数值模拟结果可发现:由于桩-土动力相互作用,致使近桩区孔压较远桩区孔压高且在桩周附近形成一定孔压梯度,但对孔压增长趋势无太大影响;数值模拟获得的地基振动孔隙水压力增长规律与试验记录基本保持一致。总的来讲,这种孔压动力增长的数值模拟方法,在强震输入下基本能够刻画土层中孔压的动力增长过程,而弱震输入下的计算误差较明显。
基金Aeronautical Science Foundation of China (02A52002), National Natural Science Foundation of China(10372043)
文摘A fast hybrid algorithm based on gridless method coupled with finite volume method （FVM） is developed for the solution to Euler equations. Compared with pure gridless method, the efficiency of the hybrid algorithm is improved to the level of finite volume method for most parts of the flow filed arc covered with grid cells. Moreover, the hybrid method is flexible to deal with the configurations as clouds of points are used to cover the region adjacent to the bodies. Mirror satellites and mirror grid cells arc introduced to the interface to accomplish data communication between the different parts of the flow field. The Euler Equations arc spatially discretized with finite volume method and gridless method in mesh and clouds of points respectively, and an explicit four-stage Runge-Kutta scheme is utilized to reach the steady-state solution. Internal flows in channels and external flows over airfoils arc investigated with hybrid method, and the solutions arc comparad to those using pure finite volume method and pure gridless method. Numerical examples show that the hybrid algorithm captures the shock waves accurately, and it is as efficient as fmite volume method.
