针对弹药装配结构复杂、零件数量多和装配效率低等问题,提出一种基于模型定义(model based definition,MBD)的弹药装配序列规划生成方法。在定义装配序列可行性的基础上,构建装配规划的适应度函数,提出包含精英种群的基于改进遗传算法(g...针对弹药装配结构复杂、零件数量多和装配效率低等问题,提出一种基于模型定义(model based definition,MBD)的弹药装配序列规划生成方法。在定义装配序列可行性的基础上,构建装配规划的适应度函数,提出包含精英种群的基于改进遗传算法(genetic algorithm,GA)的装配序列规划算法。基于UG/NX二次开发技术,设计和开发MBD的装配序列规划系统。以某引信子装配体为例进行应用验证的结果表明,所提方法有效且稳定。展开更多
为降低配电变压器潜在风险,确保故障风险控制性能,设计基于模型的工程定义(model based definition,MBD)技术的配电变压器潜在故障风险控制系统。使用MBD技术描述系统主电路,根据模块化原则将系统划分为表示层、控制层、业务逻辑层和信...为降低配电变压器潜在风险,确保故障风险控制性能,设计基于模型的工程定义(model based definition,MBD)技术的配电变压器潜在故障风险控制系统。使用MBD技术描述系统主电路,根据模块化原则将系统划分为表示层、控制层、业务逻辑层和信息访问层,运用B/S结构实现系统硬件操作。使用Java开发语言,利用在线监测、风险评价指标、故障风险控制等板块搭建系统软件,引入事故链概念,计算配电变压器失稳及支路过载故障后果,根据核心决策节点,完成潜在故障风险控制。实验结果表明,设计系统具有较好的故障风险控制性能,有效降低配电变压器潜在风险,减小潜在故障风险控制延时。展开更多
This paper focuses on the use of rotary-percussive drilling for hard rocks.In order to improve efficiency and reduce costs,it is essential to understand how operational parameters,bit wear,and drilling performance are...This paper focuses on the use of rotary-percussive drilling for hard rocks.In order to improve efficiency and reduce costs,it is essential to understand how operational parameters,bit wear,and drilling performance are related.A model is presented therein that combines multibody dynamics and discrete element method(DEM)to investigate the influences of operational parameters and bit wear on the rate of penetration and wear characteristics.The model accurately captures the motion of the bit and recreates rock using the cutting sieving result.Field experimental results validate the rod dynamic behavior,rock recreating model,and coupling model in the simulation.The findings indicate that hammer pressure significantly influences the rate of penetration and wear depth of the bit,and there is an optimal range for economical hammer pressure.The wear coefficient has a major effect on the rate of penetration,when wear coefficient is between 1/3 and 2/3.Increasing the wear coefficient can reduce drill bit button pressure and wear depth at the same drill distance.Gauge button loss increases the rate of penetration due to higher pressure on the remaining buttons,which also accelerates destruction of the bit.Furthermore,a more evenly distributed button on the bit enhances the rate of penetration(ROP)when the same number of buttons is lost.展开更多
为提高高速动车组铝合金车体部件生产效率,减少加工准备时间,实现车体部件加工准备自动化,以铝合金车体部件为研究对象,设计多层次的部件加工特征MBD(Model Based Define)模型数据结构,通过基于图的特征识别方法获取特征几何信息。在特...为提高高速动车组铝合金车体部件生产效率,减少加工准备时间,实现车体部件加工准备自动化,以铝合金车体部件为研究对象,设计多层次的部件加工特征MBD(Model Based Define)模型数据结构,通过基于图的特征识别方法获取特征几何信息。在特征识别的基础上进一步提取部件技术要求信息并与几何信息相集成,形成完整的加工特征MBD模型构建流程。根据MBD模型数据层次,结合数据库技术设计对应的数据表结构,分层次存储加工特征MBD模型,实现数据的高效存储与传递,为后续自动工艺决策与数控自动编程提供重要支撑。展开更多
文摘针对弹药装配结构复杂、零件数量多和装配效率低等问题,提出一种基于模型定义(model based definition,MBD)的弹药装配序列规划生成方法。在定义装配序列可行性的基础上,构建装配规划的适应度函数,提出包含精英种群的基于改进遗传算法(genetic algorithm,GA)的装配序列规划算法。基于UG/NX二次开发技术,设计和开发MBD的装配序列规划系统。以某引信子装配体为例进行应用验证的结果表明,所提方法有效且稳定。
文摘为降低配电变压器潜在风险,确保故障风险控制性能,设计基于模型的工程定义(model based definition,MBD)技术的配电变压器潜在故障风险控制系统。使用MBD技术描述系统主电路,根据模块化原则将系统划分为表示层、控制层、业务逻辑层和信息访问层,运用B/S结构实现系统硬件操作。使用Java开发语言,利用在线监测、风险评价指标、故障风险控制等板块搭建系统软件,引入事故链概念,计算配电变压器失稳及支路过载故障后果,根据核心决策节点,完成潜在故障风险控制。实验结果表明,设计系统具有较好的故障风险控制性能,有效降低配电变压器潜在风险,减小潜在故障风险控制延时。
基金supported by the National Natural Science Foundation of China Youth Science Foundation of China(Grant No.52308388)the Key Project of High-speed Rail Joint Fund of National Natural Science Foundation of China(Grant No.U1934210).
文摘This paper focuses on the use of rotary-percussive drilling for hard rocks.In order to improve efficiency and reduce costs,it is essential to understand how operational parameters,bit wear,and drilling performance are related.A model is presented therein that combines multibody dynamics and discrete element method(DEM)to investigate the influences of operational parameters and bit wear on the rate of penetration and wear characteristics.The model accurately captures the motion of the bit and recreates rock using the cutting sieving result.Field experimental results validate the rod dynamic behavior,rock recreating model,and coupling model in the simulation.The findings indicate that hammer pressure significantly influences the rate of penetration and wear depth of the bit,and there is an optimal range for economical hammer pressure.The wear coefficient has a major effect on the rate of penetration,when wear coefficient is between 1/3 and 2/3.Increasing the wear coefficient can reduce drill bit button pressure and wear depth at the same drill distance.Gauge button loss increases the rate of penetration due to higher pressure on the remaining buttons,which also accelerates destruction of the bit.Furthermore,a more evenly distributed button on the bit enhances the rate of penetration(ROP)when the same number of buttons is lost.
文摘为提高高速动车组铝合金车体部件生产效率,减少加工准备时间,实现车体部件加工准备自动化,以铝合金车体部件为研究对象,设计多层次的部件加工特征MBD(Model Based Define)模型数据结构,通过基于图的特征识别方法获取特征几何信息。在特征识别的基础上进一步提取部件技术要求信息并与几何信息相集成,形成完整的加工特征MBD模型构建流程。根据MBD模型数据层次,结合数据库技术设计对应的数据表结构,分层次存储加工特征MBD模型,实现数据的高效存储与传递,为后续自动工艺决策与数控自动编程提供重要支撑。
