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关于空气不偶合装药初始冲击压力计算的分析 总被引:4,自引:0,他引:4
通过对5种不偶合装药初始冲击压力计算的理论分析,阐述了几种主要方法对计算结果的影响以及计算中存在的问题。通过比较,建议采用不偶合装药初始冲击压力计算方法。 相似文献
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不耦合装药爆破孔壁压力的计算(一) 总被引:5,自引:0,他引:5
本文结合有关计算耦合装药爆破孔壁压力的流行公式,考虑不耦合装药爆孔特征及药室流场与岩石相互作用特性,推导出不耦合装药爆破孔壁压力随时间变化的关系式,此式可用于集中装药和条形装药爆破孔壁压力的计算。 相似文献
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应用爆轰和气体动力学理论,建立适当模型,分析起爆后药室流场发展全过程,作者编程计算孔壁压力等壁面参数,该程序还可分析药室内其它伴生问题,便于进行爆破机制的研究.本文介绍其理论和方法. 相似文献
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孔壁上爆炸冲击波初始参数的计算 总被引:1,自引:1,他引:0
本文应用冲击波理论,研究了耦合装药条件下孔壁上冲击波初始参数的计算,提出了一种新的孔壁压力的计算方法,并和经典的孔壁压力计算方法进行了比较。计算结果表明:对大多数岩石,该方法的计算結果与弹性波理论的计算结果基本吻合。 相似文献
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高层建筑多层地下室内人防结构顶板核爆荷载的合理确定是目前人防结构设计中亟待解决的问题。文中在对实际工程的调查基础上,研究了双层地下室的试验模型,进行了空气冲击波在地下室模型内传播的爆炸试验,分析了作用在双层地下室底层结构顶板的爆炸压力分布特性,并得出多层地下室的底层顶板核爆荷载一般要小于单层地下室顶板核爆荷载设计值的结论. 相似文献
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挡波墙对空气冲击波的削波作用研究 总被引:4,自引:1,他引:3
分析了空气中爆炸时挡波墙对冲击波的削波作用。结果表明,在爆源周围修一定高度和厚度的挡波墙可以把空气冲击波在挡波墙之后一定距离内的峰值压力削弱20%-30%,同时用数值模拟的方法计算了冲击波与挡波墙相互作用的过程,得到了在火电厂波原因有障碍物的爆炸场初始发展以及整个传播过程。数值模拟结果与实验测量和经验公式计算结果基本吻合。 相似文献
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为了探索工艺参数对内高压成形工艺的影响,实验研究了阶梯轴内高压成形中初始内压参数的作用,给出了初始内压的计算公式,完成了不同初始内压情况下的工艺实验,并对起皱、折叠等缺陷的产生原因进行了分析.研究结果表明:内高压成形过程中管坯是在轴向压应力和环向拉应力的共同作用下发生变形;初始内压的选取可参照公式(1)进行估算;对于本文的三台阶阶梯轴,初始内压以30 MPa为合理,当该值低于20 MPa时将发生折叠失稳,而高于40 MPa时将引起成形件的破裂. 相似文献
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D.Z. Yankelevsky Y.S. KarinskiV.R. Feldgun 《International Journal of Impact Engineering》2011,38(11):864-881
The paper investigates the problem of a charge exploding in soil and focuses on the characteristics of the shock wave’s peak pressure attenuation. Analysis of existing empirical data observes different attenuation factors for apparently similar certain types of soils whereas for other types of soils there is no significant difference. It was also observed that prediction of the shock wave’s peak pressure with existing power law empirical formulas yields a large discrepancy in comparison to test data. The discrepancy is significant even in case where the specific tested soil parameters are used. These observations among others motivated this study. The power law relationship has been investigated through numerical simulations of the shock wave propagation in different soils. The soil is modeled as a bulk irreversible compressible elastic plastic medium, including full bulk locking and dependence of the current deviatoric yield stress on the pressure. The Lagrange approach and the modified variational difference methods are used to simulate the process. The study shows that the shock wave’s peak pressure attenuation for certain types of soils may be well presented by a power law with a constant exponent, whereas other types of soils may be presented by a power law for a limited distance range and their behavior for a wide distance range is poorly described by a linear relationship on a logarithmic scale but is well represented by a bi-linear or a tri-linear realtionship. These findings explain some of the above mentioned observations. 相似文献
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Nonlinear numerical study of crack initiation and propagation in a reactor pressure vessel under pressurized thermal shock using XFEM 下载免费PDF全文
Under pressurized thermal shock (PTS), once crack initiation occurs in a reactor pressure vessel (RPV), the stress concentration around the crack tips may result in local instability and crack propagation. The temperature‐dependent material properties are introduced into the finite element analysis model. According to the response of the transient temperature field and stress field near the crack tip region, the influence of PTS on the carrying capacity of the structure is demonstrated. Also, the process of crack initiation and propagation is simulated by using the extended finite element method (XFEM). The results show that the crack of mode I is easy to be initiated on the nozzle in the initial high temperature and high pressure working state. The effect of cladding on the RPV integrity is enhanced with the increase of crack size, and it mainly depends on the crack length. During the PTS transient, a discontinuity of stress exists near the cladding‐base interface, and the cladding bears more loading than the base of the same size. As the unloading of the internal pressure, the stress does not decline due to the strong thermal shock. In the late stage of the PTS process, the internal pressure caused by repressurization poses a challenge to the strength of the structure. With the decrease of the base wall thickness, the allowable repressure value also gradually decreases. However, the increase of the base wall thickness causes the rise of thermal stress, and the allowable repressure load is not significantly improved. 相似文献