Pressure-impulse diagram with multiple failure modes of one-way reinforced concrete slab under blast loading using SDOF method

Two loosely coupled single degree of freedom (SDOF) systems were used to model the flexural and direct shear responses of one-way reinforced concrete slabs subjected to explosive loading. Blast test results show that the SDOF systems are accurate in predicting the failure mode of the slab under blast loads by incorporating the effects of the strain rate effect caused by rapid load application. Based on different damage criteria, pressure-impulse (P-I) diagrams of the two failure modes were analyzed with the SDOF systems. The effects of span length, concrete strength, and reinforcement ratio of the slab on the P-I diagram were also investigated. Results indicate that a slab tends to fail in direct shear mode when it is of a smaller span length and tends to fail in flexure mode when it is of a larger span length. With the increase of the concrete strength or reinforced ratio, both the flexure and shear capacity increase. Based on numerical results, a simplified method and a semi analytical equation for deriving the P-I diagram are proposed for different failure modes and damage levels.     

Fluid flow characteristics of single inclined circular jet impingement for ultra-fast cooling

The fluid flow characteristics of the single bunch inclined jet impingement were investigated with different jet flow velocities, nozzle diameters, jet angles and jet-to-target distances for ultra-fast cooling technology. The results show that the peak pressure varying significantly from nearly 0.5 to above 13.4 kPa locates at the stagnation point with different jet diameters, and the radius of impact pressure affected zone is small promoted from 46 to 81 mm in transverse direction, and 50 to 91 mm in longitude direction when the jet flow velocity changes from 5 to 20 m/s. However, the fluid flow velocity is relatively smaller near the stagnation point, and increases gradually along the radius outwards, then declines. There is an obvious anisotropic characteristic that the flow velocity component along the jet direction is about twice of the contrary one where the jet anlge is 60°, jet diameter is 5 mm, jet length is 8 mm and jet height is 50 mm.     

压力敏感性储层超前注水开发研究

压力敏感性储层在开发过程中,储层渗透率随储层压力的降低而下降,进而影响油井产量及油田开发效果。为了量化地层压力变化对压力敏感性储层开发的影响,通过实验研究得出了储层渗透率随地层压力的变化规律。进而建立了压力敏感性储层渗透率及油井产量随地层压力的变化关系,并结合油田开发实例,研究了超前注水在压力敏感性储层开发中应用效果。     

基于FSK调制模式的新型胎压监测系统开发(英文)

分析了间接式胎压监测系统(TPMS)的不足,并基于FSK信号调制模式抗噪声强的特点,开发了一种新的直接式胎压监测系统.该系统由轮胎压力传感器和胎压控制器组成:轮胎压力传感器采用高集成复合芯片SP37实现轮胎内部压力、温度、加速度等信息的检测和发射,体积小、重量轻;胎压控制器以8位单片机控制射频接收器MC33596实现无线数据的接收、显示和报警.基于素数的动态延时算法和节能策略,降低了多个传感器同时发射时发生连续数据冲突的概率,在满足系统监测实时性的前提下延长了工作寿命.实车测试效果表明,该系统数据接收灵敏度可达到-100 dBm,在汽车时速100 km时工作很稳定.     

一种基于主汽压预测的火电机组负荷控制方法

针对火电机组因锅炉大惯性导致负荷响应慢、汽压波动大等问题,提出一种基于主汽压预测的火电机组负荷控制方法.该方法以锅炉跟随控制方式为基础,根据预测模型,由负荷指令和当前燃烧率预测出主汽压变化趋势,根据预测主汽压与当前主汽压偏差来修正锅炉侧的能量需求,以超前改变入炉能量,提高机组的负荷响应速率,减少主汽压波动.以某1 000 MW超超临界机组为例,建立其压力预测模型并进行负荷控制阶跃仿真实验,结果表明:采用该方法使得燃料量控制兼顾快速性和准确性,能有效改善机炉之间协调特性,使机组负荷响应快、超调量小,同时主汽压波动小.     

液化气储罐监造检验工艺探讨

结合液化石油气储罐的设计结果,结合相关技术标准对其制造工艺流程、监造要点与检验等问题进行了分析与探讨,对于相关压力容器的制造、监造与检验工作具有一定的借鉴价值.     

一种有创血压模拟器的设计

针对有创血压测量设备研发阶段、校准测试或在教学实验中难以采用人体或动物来做试验的缺点,提出一种新型有创血压模拟器设计方法。该模拟器通过微控制器产生正弦波和各种人体血压波形,输送到扬声器产生振动,利用传动模块和压力传感器将压力变化值传送到上位机作显示分析。实验表明该模拟器具有精度高、波形显示速度快的特点。     

川东北碳酸盐岩层地层压力预测方法

准确预测碳酸盐岩层地层压力的难度较大,给钻井设计和施工造成不利的影响。针对碳酸盐岩层异常压力成因复杂和不符合压实规律的特征,利用纵波波速与地层物性参数之间关系的综合参数模型,借助川东北普光地区碳酸盐岩层的测井数据,使用逐步回归和多元非线性回归相结合的方法,来预测碳酸盐岩层的地层压力。结果表明,地层压力预测平均误差小于10%,精度满足工程需要。因此,综合参数模型可用于碳酸盐岩层地层压力的预测。