鲁基厂水电站尾水洞围岩稳定分析

采用非线性弹塑性有限元方法,根据地下洞室施工开挖过程及锚固方法,对云南鲁基厂水电站尾水洞进行了正常开挖工况及施工完建地震工况下围岩稳定分析计算。分析结果表明设计采用的锚喷及衬砌支护方案基本合理。采用的弹塑性有限元基本理论及支护计算方法、洞室支护方案等对同类工程的设计、施工具有一定的参考意义。     

阿海水电站主厂房和副厂房三维有限元结构分析

采用有限元计算软件ANSYS,对阿海水电站主厂房及下游副厂房在各工况下其应力和变形进行了三维有限元分析,根据结构各部位的应力分析结果,计算结构配筋,并与类似工程施工图配筋进行对比,为施工图设计配筋提供依据。     

板桩式海堤结构有限元数值模拟分析

为改变浙江沿海海堤功能单一,土石料用量大的缺点,开展新型海堤结构研究。对板桩式海堤结构进行有限元数值模拟研究,分析在竖向荷载及回填土压力作用下,结构的变形及承载能力。可以得出,桩土的位移量均不大,土体未发生明显的塑性变形,桩身应力不大,可进行实际工程的应用。     

某单机无穷大电力系统暂态稳定性分析仿真

电力系统是一个复杂的动态系统,系统一旦出现稳定性问题,可能会在较短的时间内发生严重后果,因此,在电力系统规划、设计、运行等工作中都要进行大量的暂态稳定分析。介绍了电力系统时域仿真数学模型,构建了单机无穷大系统仿真模型。仿真结果表明:故障切除时间越短,发电机阻尼越大,系统越容易稳定,且在单相短路接地故障情况下系统最容易稳定。     

纳子峡面板砂砾石坝渗流性态三维有限元分析

根据纳子峡水电站工程坝址区地形地质条件,建立了坝址区三维渗流有限元模型,计算分析了正常蓄水、设计洪水和校核洪水3种工况下坝体及坝基的稳定渗流场,获得了坝体和坝基的位势分布、坝体各分区的渗透坡降及渗透流量等。计算结果表明,在各种工况下坝体及坝基的渗流场符合一般规律,混凝土面板及防渗帷幕等组成的防渗系统可消减水头84%以上,其作用明显;混凝土面板及坝基防渗帷幕的渗透坡降较大,垫层、砂砾料区等的渗透坡降很小,坝体各分区的渗透坡降均小于材料的容许渗透坡降,大坝防渗排水系统的设计在技术上是合理的。     

Influences of denucleation on contact force of facet joints under whole body vibration

To investigate the influence of the injured disc, frequency, load and damping on the facet contact forces of the low lumbar spine on the condition of whole body vibration, a detailed 3-D nonlinear finite element model was created based on the actual geometrical data of embalmed vertebrae of lumbar spine. The denucleation and facetectomy, together with removal of the capsular ligaments was employed to mimic the injury conditions of lumbar spine after surgery. The compression cyclic force was assumed to mimic the dynamic loads of transport vehicles. The results show that the high frequency vibration might increase both of the value and the vibration amplitude of facet contact forces of the lumbar spine under whole body vibration. The nucleus removal may increase significantly the facet contact forces. Although damping can decrease the vibration amplitude of facet contact forces for intact models, it has less effect on the vibration amplitude of facet contact force for the denucleated models. The denucleation of intervertebral discs is more harmful to the facet articulation on the condition of whole body vibration.     

桩周土开挖条件下桩基础承载特性数值分析

运用桩基础支撑上部既有建筑物地下增层的过程中,随着桩周土减少和桩基础的暴露,桩的承载特性会出现明显变化.文章运用ANSYS有限元程序分析了桩周土开挖前、后以及不同开挖深度等工况下,桩基础承载特性的变化规律.结果表明：随着桩周土开挖深度增大,被开挖段的桩身侧阻力消失,需要增加未开挖部分桩身侧阻力、桩端阻力来增强桩身轴力.同时,也需增大桩基沉降量和桩土间的滑移量.     

Impact Dynamics of Supercavitating Projectile with Fluid/Structure Interaction

As supercavitating projectiles move at high speed, the periodic impacts ("tail-slap") on the interior surface of the cavity generally occur due to disturbances. The interactions between the projectile and the water/cavity interface are the sources of structural vibrations, which affect the guidance of the vehicle and undermine the structural reliability. The Fluid/Structure Interaction calculation procedure of the tail-slaps of supercavitating projectile is established, and the dynamic behaviours of the projectile operating in tail-slap conditions with and without considering Fluid/Structure Interaction are obtained and compared. The responses of the projectile riding a reducing cavity are studied, and the effect of Fluid/Structure Interaction is also analyzed. The results show that the angular velocity of projectile increases as the body slowing down, and the amplitude of the elastic displacement response decreases at the beginning and increases when the cavity size is close to the diameter of the tail of projectile. The effect of Fluid/Structure Interaction reduces the amplitudes and frequencies of the impact loads and the vibration responses of the body, and when the speed is higher, the effect is more apparent.