Experimental and numerical investigations were carried out on the free-free end ring-stiffened cylinder subjected to underwater explosion loading. Numerical analysis was carried out by using the MSC.DYTRAN finite elem...Experimental and numerical investigations were carried out on the free-free end ring-stiffened cylinder subjected to underwater explosion loading. Numerical analysis was carried out by using the MSC.DYTRAN finite element code and the results were compared with experiment results. General coupling was used to simulate the interaction between fluid and structure. The strain rate effect, geometric nonlinearity and initial abnormity in shape were considered. The effective plastic stress and the strain of shell between ribs on different locations were compared and damage mechanism were analyzed..展开更多
Buried high explosive(HE) charges represent a high threat to military vehicles. The detonation of these charges can lead to significant momentum transfer onto vehicles and their occupants. A detailed understanding of ...Buried high explosive(HE) charges represent a high threat to military vehicles. The detonation of these charges can lead to significant momentum transfer onto vehicles and their occupants. A detailed understanding of the physical processes involved in the loading of vehicle structures is necessary for an optimization of effective countermeasures and protection systems. A quantitative description of the local momentum distribution on the vehicle underbody due to the detonation process is of special importance. In the following, a new test setup is presented that allows the experimental determination of the specific impulse distribution. It is based on a ring arrangement where the elements are nested into each other and the velocity of each ring is correlated with the local specific impulse at its position.The momentum transfer to a vehicle depends on a number of influencing factors such as: charge mass,embedding material(e.g. sand, gravel, clay), density, water content, saturation, depth of burial, ground clearance and vehicle shape. The presented technology is applied to quantify the influence of the embedding material(alluvial sand, quartz sand), the burial depth and the water content on the local specific impulse distribution. The obtained data can be used as initial condition for the numerical simulation of occupant safety assessment and as input for empirical modeling of momentum transfer on structures.展开更多
为探究凸型加筋锥柱壳在静水压与深水爆炸载荷联合作用下的动态响应,在塑性弦线模型基础上考虑静水压载荷、锥角因素,将问题简化为求解拥有初边界值的波动方程,利用特征值展开将肋间板壳径向位移表示为无穷级数的形式,并对每个特征值计...为探究凸型加筋锥柱壳在静水压与深水爆炸载荷联合作用下的动态响应,在塑性弦线模型基础上考虑静水压载荷、锥角因素,将问题简化为求解拥有初边界值的波动方程,利用特征值展开将肋间板壳径向位移表示为无穷级数的形式,并对每个特征值计算相应的卸载时间,以此显示冲击波载荷的衰减特性。使用有限元程序Abaqus对半锥角为20°的凸型加筋锥柱壳开展最大深度500 m、最大冲击因子0.79 kg 0.5/m的水下爆炸数值模拟研究,对邻近结合处的柱段、锥段肋间板壳的理论模型计算结果进行验证对比和讨论。研究结果表明:与不计静水压相比,静水压使得肋间板壳刚度减小——最大位移出现时刻延滞,最终径向位移随水深而增大;在不同冲击因子下,理论模型与数值模拟最终径向位移误差最大为21.7%(锥段),最小为2.0%(柱段);由于锥角的存在,肋间板壳位移不再关于中心点对称分布,中心点最终位移较柱段减小40%以上。展开更多
文摘Experimental and numerical investigations were carried out on the free-free end ring-stiffened cylinder subjected to underwater explosion loading. Numerical analysis was carried out by using the MSC.DYTRAN finite element code and the results were compared with experiment results. General coupling was used to simulate the interaction between fluid and structure. The strain rate effect, geometric nonlinearity and initial abnormity in shape were considered. The effective plastic stress and the strain of shell between ribs on different locations were compared and damage mechanism were analyzed..
文摘Buried high explosive(HE) charges represent a high threat to military vehicles. The detonation of these charges can lead to significant momentum transfer onto vehicles and their occupants. A detailed understanding of the physical processes involved in the loading of vehicle structures is necessary for an optimization of effective countermeasures and protection systems. A quantitative description of the local momentum distribution on the vehicle underbody due to the detonation process is of special importance. In the following, a new test setup is presented that allows the experimental determination of the specific impulse distribution. It is based on a ring arrangement where the elements are nested into each other and the velocity of each ring is correlated with the local specific impulse at its position.The momentum transfer to a vehicle depends on a number of influencing factors such as: charge mass,embedding material(e.g. sand, gravel, clay), density, water content, saturation, depth of burial, ground clearance and vehicle shape. The presented technology is applied to quantify the influence of the embedding material(alluvial sand, quartz sand), the burial depth and the water content on the local specific impulse distribution. The obtained data can be used as initial condition for the numerical simulation of occupant safety assessment and as input for empirical modeling of momentum transfer on structures.
文摘为探究凸型加筋锥柱壳在静水压与深水爆炸载荷联合作用下的动态响应,在塑性弦线模型基础上考虑静水压载荷、锥角因素,将问题简化为求解拥有初边界值的波动方程,利用特征值展开将肋间板壳径向位移表示为无穷级数的形式,并对每个特征值计算相应的卸载时间,以此显示冲击波载荷的衰减特性。使用有限元程序Abaqus对半锥角为20°的凸型加筋锥柱壳开展最大深度500 m、最大冲击因子0.79 kg 0.5/m的水下爆炸数值模拟研究,对邻近结合处的柱段、锥段肋间板壳的理论模型计算结果进行验证对比和讨论。研究结果表明:与不计静水压相比,静水压使得肋间板壳刚度减小——最大位移出现时刻延滞,最终径向位移随水深而增大;在不同冲击因子下,理论模型与数值模拟最终径向位移误差最大为21.7%(锥段),最小为2.0%(柱段);由于锥角的存在,肋间板壳位移不再关于中心点对称分布,中心点最终位移较柱段减小40%以上。
