When an expanded-base pile is installed into ground, the cavity expansion associated with penetration of the enlarged pile base is followed by cavity contraction along the smaller-diameter pile shaft. In order to acco...When an expanded-base pile is installed into ground, the cavity expansion associated with penetration of the enlarged pile base is followed by cavity contraction along the smaller-diameter pile shaft. In order to account for the influence of cavity contraction on the change of bearing capacity of expanded-base pile, a theoretical calculation methodology, predicting the setup of expanded-base pile, was established by employing the cavity contraction theory to estimate the shaft resistance of expanded-base pile, and horizontal consolidation theory to predict the dissipation of excess pore pressure. Finally, the numerical solutions for the setup of expanded-base pile were obtained. The parametric study about the influence of cavity contraction on setup of expanded-base pile was carried out, while a field test was introduced. The parametric study shows that the decrements in radial pressure and the maximum pore water pressure after considering cavity contraction are increased as the expanded ratio(base diameter/shaft diameter) and rigidity index of soil are raised. The comparison between calculated and measured values shows that the calculated results of ultimate bearing capacity for expanded-base pile considering cavity contraction agree well with the measured values; however, the computations ignoring cavity contraction are 2.5-3.0 times the measured values.展开更多
When producing special-shape spring in CNC spring coiler,the setup of the coiler is often a manual work using a trial-and-error method.As a result,the setup of coiler consumes so much time and becomes the bottleneck o...When producing special-shape spring in CNC spring coiler,the setup of the coiler is often a manual work using a trial-and-error method.As a result,the setup of coiler consumes so much time and becomes the bottleneck of the spring production process.In order to cope with this situation,this paper proposes an automatic generation system of setup for CNC spring coiler us- ing case-based reasoning(CBR).The core of the study contains:(1)integrated reasoning model of CBR system;(2)spatial shape describe of special-shape spring based on feature;(3)coiling case representation using shape feature matrix;and(4)case similari- ty measure algorithm.The automatic generation system has implemented with C++Builder 6.0 and is helpful in improving the automaticity and efficiency of spring coiler.展开更多
针对制造行业中广泛存在的一类复杂并行机调度问题,即带到达时间、多工序、加工约束和序相关设置时间的并行机调度问题(Parallel machine scheduling problem with arrival time, multiple operations, process restraints and sequence...针对制造行业中广泛存在的一类复杂并行机调度问题,即带到达时间、多工序、加工约束和序相关设置时间的并行机调度问题(Parallel machine scheduling problem with arrival time, multiple operations, process restraints and sequencedependent setup times, PMSP AMPS),建立问题的排序模型并提出一种混合离散教与学优化算法进行求解,优化目标为最小化最大完工时间.首先,根据标准教与学算法(Teaching-learning-based optimization, TLBO)中两阶段个体更新公式的特点,在保留每一阶段个体更新公式框架不变的前提下,对公式中具体改变实数个体或向量的每个核心操作均用所设计的排列操作进行替换,使其可直接在离散问题解空间中执行基于标准教与学算法机理的全局搜索,从而明显提高了原算法的全局搜索效率.其次,采用交换操作和插入操作构造了一种简洁有效地变邻域局部搜索,对全局搜索发现的优质解区域进行细致搜索,从而进一步增强了算法的性能.通过对不同测试问题的仿真实验和算法比较,验证了所提算法可有效求解PMSP AMPS.展开更多
基金Project(LQ15E080002)supported by Zhejiang Provincial Natural Science Foundation of ChinaProjects(5150828251478228)supported by the National Natural Science Foundation of China
文摘When an expanded-base pile is installed into ground, the cavity expansion associated with penetration of the enlarged pile base is followed by cavity contraction along the smaller-diameter pile shaft. In order to account for the influence of cavity contraction on the change of bearing capacity of expanded-base pile, a theoretical calculation methodology, predicting the setup of expanded-base pile, was established by employing the cavity contraction theory to estimate the shaft resistance of expanded-base pile, and horizontal consolidation theory to predict the dissipation of excess pore pressure. Finally, the numerical solutions for the setup of expanded-base pile were obtained. The parametric study about the influence of cavity contraction on setup of expanded-base pile was carried out, while a field test was introduced. The parametric study shows that the decrements in radial pressure and the maximum pore water pressure after considering cavity contraction are increased as the expanded ratio(base diameter/shaft diameter) and rigidity index of soil are raised. The comparison between calculated and measured values shows that the calculated results of ultimate bearing capacity for expanded-base pile considering cavity contraction agree well with the measured values; however, the computations ignoring cavity contraction are 2.5-3.0 times the measured values.
基金Supported by the Doctoral Programme Foundation of Education Ministry of China under the grant(No.20050699033)
文摘When producing special-shape spring in CNC spring coiler,the setup of the coiler is often a manual work using a trial-and-error method.As a result,the setup of coiler consumes so much time and becomes the bottleneck of the spring production process.In order to cope with this situation,this paper proposes an automatic generation system of setup for CNC spring coiler us- ing case-based reasoning(CBR).The core of the study contains:(1)integrated reasoning model of CBR system;(2)spatial shape describe of special-shape spring based on feature;(3)coiling case representation using shape feature matrix;and(4)case similari- ty measure algorithm.The automatic generation system has implemented with C++Builder 6.0 and is helpful in improving the automaticity and efficiency of spring coiler.
文摘针对制造行业中广泛存在的一类复杂并行机调度问题,即带到达时间、多工序、加工约束和序相关设置时间的并行机调度问题(Parallel machine scheduling problem with arrival time, multiple operations, process restraints and sequencedependent setup times, PMSP AMPS),建立问题的排序模型并提出一种混合离散教与学优化算法进行求解,优化目标为最小化最大完工时间.首先,根据标准教与学算法(Teaching-learning-based optimization, TLBO)中两阶段个体更新公式的特点,在保留每一阶段个体更新公式框架不变的前提下,对公式中具体改变实数个体或向量的每个核心操作均用所设计的排列操作进行替换,使其可直接在离散问题解空间中执行基于标准教与学算法机理的全局搜索,从而明显提高了原算法的全局搜索效率.其次,采用交换操作和插入操作构造了一种简洁有效地变邻域局部搜索,对全局搜索发现的优质解区域进行细致搜索,从而进一步增强了算法的性能.通过对不同测试问题的仿真实验和算法比较,验证了所提算法可有效求解PMSP AMPS.
