The dynamic analysis of a pipe system is one of the most crucial problems for the entire mining system. A discrete element method （DEM） is proposed for the analysis of a deep-ocean mining pipe system, including the ...The dynamic analysis of a pipe system is one of the most crucial problems for the entire mining system. A discrete element method （DEM） is proposed for the analysis of a deep-ocean mining pipe system, including the lift pipe, pump, buffer and flexible hose. By the discrete element method, the pipe is divided into some rigid elements that are linked by flexible connectors. First, two examples representing static analysis and dynamic analysis respectively are given to show that the DEM model is feasible. Then the three-dimensional DEM model is used for dynamic analysis of the mining pipe system. The dynamic motions of the entire mining pipe system under different work conditions are discussed. Some suggestions are made for the actual operation of deep-ocean mining systems.展开更多
On the basis of the thermal-elastic-plastic theory, a three-dimensional finite element numerical simulation is performed on the girth welded residual stresses of the duplex stainless steel pipe with ANSYS nonlinear fi...On the basis of the thermal-elastic-plastic theory, a three-dimensional finite element numerical simulation is performed on the girth welded residual stresses of the duplex stainless steel pipe with ANSYS nonlinear finite element program for the first time. Three-dimensional FEM using mobile heat source for analysis transient temperature field and welding stress field in circumferential joint of pipes is founded. Distributions of axial and hoop residual stresses of the joint are investigated. The axial and the hoop residual stresses at the weld and weld vicinity on inner surface of pipes are tensile, and they are gradually transferred into compressive with the increase of the departure from the weld. The axial residual stresses at the weld and weld vicinity on outer surface of pipes is compressive while the hoop one is tensile. The distributions of residual stresses compared positive-circle with negative-circle show distinct symmetry. These results provide theoretical knowledge for the optimization of process and the control of welding residual stresses.展开更多
Numerical simulation concerning the forming and welding process of spiral welded pipe was conducted, which included three steps ： the first step was the stress analysis when the spiral was formed, and then the stress...Numerical simulation concerning the forming and welding process of spiral welded pipe was conducted, which included three steps ： the first step was the stress analysis when the spiral was formed, and then the stress was regarded as initial condition of melding during the temperature field analysis in the process of welding, the last step was the thermal stress analysis of the weld seam after the welding was over. Moreover, when the steel strip was pushed, the stress was also calculated by non-linearity contact technology using Abaqus Software. By finite element modeling and calculating of the forming and welding process of the spiral welded pipe, the key points of the multi-fields synthetic simulating were studied and discussed.展开更多
煤矿井下复杂施工环境导致超前钻探中钻具响应与岩性映射关系通常难以直接建立,制约岩性识别精度。针对此问题,构建了聚晶金刚石复合片(PDC)钻头-钻杆破岩仿真模型,揭示了不同钻进条件下钻具对复合岩层的响应特征:固定钻速,提升转速会...煤矿井下复杂施工环境导致超前钻探中钻具响应与岩性映射关系通常难以直接建立,制约岩性识别精度。针对此问题,构建了聚晶金刚石复合片(PDC)钻头-钻杆破岩仿真模型,揭示了不同钻进条件下钻具对复合岩层的响应特征:固定钻速,提升转速会使钻头扭矩降低且波动减弱,而钻压波动相对稳定;固定转速,提升钻速会使钻压与扭矩同步升高。钻杆三轴向振动加速度随转速增大而增大,随钻速增大呈先减小后增大趋势。在岩性界面处,上述参数呈现突变特征,表明多参数联合可作为岩性识别特征。基于此,提出了一种融合双向长短期记忆网络(BiLSTM)、注意力机制与KAN(Kolmogorov-Arnold Network)的岩性识别模型——BiLSTM-Att-KAN,以KAN替代BiLSTM模型中多层感知机(MLP)分类器,突破MLP因使用Sigmoid/Rectified Linear Unit(ReLU)等固定激活函数导致的非线性映射局限,可提高复杂岩性识别精度。利用仿真数据和实际数据进行模型测试,结果表明:BiLSTM-Att-KAN在仿真数据集上的识别准确率达91.64%,优于K近邻、随机森林等传统分类模型,提升幅度7.00%~22.08%;在实际训练钻孔数据测试集与独立测试数据上的准确率分别为86.81%和85.28%,验证了模型有效性,可为煤系地层岩性识别提供技术支撑。展开更多
A set of serf-developed apparatus for foundation physical model were utilized to conduct model tests of the multi-element composite foundation with a steel pipe pile and several gravel piles. Some load-bearing charact...A set of serf-developed apparatus for foundation physical model were utilized to conduct model tests of the multi-element composite foundation with a steel pipe pile and several gravel piles. Some load-bearing characteristics of the multi-element Composite foundation, including the curves of foundation settlement, stresses of piles, pile-soil stress ratio, and load-sharing ratio of piles and soil, were obtained to study its working performances in silty sand soil. The experimental results revealed that the multi-element composite foundation with steel pipe pile and gravel pile contributed more than the gravel pile composite foundation in improving the bearing capacity of the silty fine sand.展开更多
基金This researchis part of a project financially supported by the National Natural Science Goundation of China(GrantNo.50275152)National Deep-Sea Technology Project of Development and Research.(Grant No.DY105-3-2-2)
文摘The dynamic analysis of a pipe system is one of the most crucial problems for the entire mining system. A discrete element method （DEM） is proposed for the analysis of a deep-ocean mining pipe system, including the lift pipe, pump, buffer and flexible hose. By the discrete element method, the pipe is divided into some rigid elements that are linked by flexible connectors. First, two examples representing static analysis and dynamic analysis respectively are given to show that the DEM model is feasible. Then the three-dimensional DEM model is used for dynamic analysis of the mining pipe system. The dynamic motions of the entire mining pipe system under different work conditions are discussed. Some suggestions are made for the actual operation of deep-ocean mining systems.
文摘On the basis of the thermal-elastic-plastic theory, a three-dimensional finite element numerical simulation is performed on the girth welded residual stresses of the duplex stainless steel pipe with ANSYS nonlinear finite element program for the first time. Three-dimensional FEM using mobile heat source for analysis transient temperature field and welding stress field in circumferential joint of pipes is founded. Distributions of axial and hoop residual stresses of the joint are investigated. The axial and the hoop residual stresses at the weld and weld vicinity on inner surface of pipes are tensile, and they are gradually transferred into compressive with the increase of the departure from the weld. The axial residual stresses at the weld and weld vicinity on outer surface of pipes is compressive while the hoop one is tensile. The distributions of residual stresses compared positive-circle with negative-circle show distinct symmetry. These results provide theoretical knowledge for the optimization of process and the control of welding residual stresses.
基金Funded by Scientific Research Key Program of Beijing Municipal Commission of Education(KZ200610017010)Beijing Elitist Program Project(20041D0500517).
文摘Numerical simulation concerning the forming and welding process of spiral welded pipe was conducted, which included three steps ： the first step was the stress analysis when the spiral was formed, and then the stress was regarded as initial condition of melding during the temperature field analysis in the process of welding, the last step was the thermal stress analysis of the weld seam after the welding was over. Moreover, when the steel strip was pushed, the stress was also calculated by non-linearity contact technology using Abaqus Software. By finite element modeling and calculating of the forming and welding process of the spiral welded pipe, the key points of the multi-fields synthetic simulating were studied and discussed.
文摘煤矿井下复杂施工环境导致超前钻探中钻具响应与岩性映射关系通常难以直接建立,制约岩性识别精度。针对此问题,构建了聚晶金刚石复合片(PDC)钻头-钻杆破岩仿真模型,揭示了不同钻进条件下钻具对复合岩层的响应特征:固定钻速,提升转速会使钻头扭矩降低且波动减弱,而钻压波动相对稳定;固定转速,提升钻速会使钻压与扭矩同步升高。钻杆三轴向振动加速度随转速增大而增大,随钻速增大呈先减小后增大趋势。在岩性界面处,上述参数呈现突变特征,表明多参数联合可作为岩性识别特征。基于此,提出了一种融合双向长短期记忆网络(BiLSTM)、注意力机制与KAN(Kolmogorov-Arnold Network)的岩性识别模型——BiLSTM-Att-KAN,以KAN替代BiLSTM模型中多层感知机(MLP)分类器,突破MLP因使用Sigmoid/Rectified Linear Unit(ReLU)等固定激活函数导致的非线性映射局限,可提高复杂岩性识别精度。利用仿真数据和实际数据进行模型测试,结果表明:BiLSTM-Att-KAN在仿真数据集上的识别准确率达91.64%,优于K近邻、随机森林等传统分类模型,提升幅度7.00%~22.08%;在实际训练钻孔数据测试集与独立测试数据上的准确率分别为86.81%和85.28%,验证了模型有效性,可为煤系地层岩性识别提供技术支撑。
基金The National Natural Science Foundation of China (No.50478090)
文摘A set of serf-developed apparatus for foundation physical model were utilized to conduct model tests of the multi-element composite foundation with a steel pipe pile and several gravel piles. Some load-bearing characteristics of the multi-element Composite foundation, including the curves of foundation settlement, stresses of piles, pile-soil stress ratio, and load-sharing ratio of piles and soil, were obtained to study its working performances in silty sand soil. The experimental results revealed that the multi-element composite foundation with steel pipe pile and gravel pile contributed more than the gravel pile composite foundation in improving the bearing capacity of the silty fine sand.
