基于概率破舱的载荷计算方法及弯曲剩余强度分析研究

基于NAPA软件对某甲板货船进行建模分舱,计算了船舶概率破舱后三个初始工况下所有破损组合的弯矩值,并采用VB编程语言产生最大弯矩包络曲线;对破损后船舶的弯曲剩余强度进行了确定性分析研究,分析并得出了满足许用应力时舷顶和舭部所允许的最大破损范围。概率破舱载荷计算结果较为安全可信,且弯曲剩余强度分析方法对船舶破损时强度的判断有一定的参考作用。     

Monitoring of ship damage condition during stranding

This study proposes a new procedure for the estimation of stranding forces and their contact positions. The method is based on the measurement of a few characteristic on-site parameters, i.e., the draughts and bending moments acting on a stranded ship. A procedure that estimates penetration into the ship bottom based on knowledge of the resistance versus penetration relationship is also presented. The seabed topology is parameterized by a paraboloid. This geometry can, in principle, characterize a wide range of obstructions, from sharp rocks to large shoals. Nonlinear finite element analysis is used to simulate various stranding situations and to generate the corresponding resistance versus penetration curves. The present method provides insight into the identification of real stranding scenarios in terms of the location of obstructions, their possible shapes and the corresponding resistance-penetration curves. The proposed methodology represents a first step towards a tool for quick decision making during salvage operations. The ultimate goal is to allow near real-time prediction of the risk of penetration into cargo tanks and hull girder failure. To demonstrate the effectiveness of the proposed method, it is applied to a simulated trial stranding scenario.     

轿车白车身弯扭刚度试验和仿真对比

静刚度在评价汽车安全性与舒适性方面具有举足轻重的作用,白车身刚度试验和仿真是获取刚度参数值的有效手段。文章论述了轿车白车身静态弯曲和扭转刚度试验,并综合考虑对白车身刚度影响的区域,对比分析了不同加载工况下的试验和仿真计算结果,表明弯曲和扭转刚度及门窗调扣变形试验和仿真数据能定量分析车身重要部位的强度,为提出加强或减弱结构的有效措施提供了依据。     

152QMI型发动机连杆弯曲、断裂原因分析与受力计算

152QMI型发动机是各型号发动机中连杆最易弯曲、断裂的机型之一。经过分析检查, 引起连杆弯曲变形或断裂的原因是:1)连杆承受巨大压力及一定的弯矩,连杆受弯后,使活塞销通油孔处应力集中,强度下降;2)连杆小头孔中心与连杆小头孔毛坯外圆中心不同心,使一边孔壁变薄,强度下降。     

高压共轨柴油机低温起动过程试验研究

对采用高压共轨燃油喷射技术的某直列六缸增压中冷柴油机进行了低温低气压起动试验,分析了低温和低气压环境对柴油机起动过程的影响,以及高压共轨柴油机改善低温起动性能所采用的控制策略.结果表明,该柴油机在Om海拔、-35℃的模拟环境下能够顺利起动,起动时间为23 s;在3000m模拟海拔、-30℃模拟环境下,起动困难,起动拖动...