In order to solve the problem of surrounding rock control in soft coal seam roadway, taking the centralized return airway of No. 2 coal seam in Liangdu Coal Industry as the research background, the mechanical con...In order to solve the problem of surrounding rock control in soft coal seam roadway, taking the centralized return airway of No. 2 coal seam in Liangdu Coal Industry as the research background, the mechanical conditions of roadway surrounding rock were analyzed by means of field investigation, rock mechanics experiment and numerical simulation. The design principles of roadway support in soft coal seam were put forward: high strength anchor cable support, high preload support and high stiffness support. The bearing capacity of surrounding rock was strengthened by anchor cable support, and the deformation and failure of surrounding rock were effectively controlled. Through the numerical simulation method, the deformation and plastic failure range of roadwaysunder different support schemes are compared and analyzed. The support scheme of centralized transportation roadway is studied and determined, and the field test is carried out, which effectively controls the deformation of surrounding rock of roadway in weak coal seam.展开更多
With the considerable applications of ceramic matrix composites(CMC) in aircraft engineering, the design of CMC bolted joint gains paramount attention because of its capacity to to improve load-bearing efficiency of a...With the considerable applications of ceramic matrix composites(CMC) in aircraft engineering, the design of CMC bolted joint gains paramount attention because of its capacity to to improve load-bearing efficiency of aircraft key structure. In this work, a 3 D finite element model was established to predict tensile performance and failure modes of single-lap, single-bolt 2 D C/SiC composite, and superalloy joint, which considers the progressive damage behavior of 2 D woven C/SiC composites. On the basis of the developed progressive damage model, a parametric study was carried out to illustrate the effects of bolt preload and bolt-hole clearance on mechanical behaviors of the hybrid bolted joint. It was found that the increase in the value of bolt preload made the failure load grow first and then drop, and the optimum value of bolt preload 5.00 kN generated 56.47% rise in the initial failure load and 22.83% rise in the final failure load for the bolted joint in comparison with zero preload case. As the clearance increased from 0 to 2.00%, the initial and final failure loads respectively declined by 45.88% and 24.02% for 2.00% bolt-hole clearance relative to the neat-fit case. The loss in failure loads can be reduced to compressive stress concentration around the fastening hole-edge area, leading to the appearance of earlier damages by the introduction of increasing bolt hole clearance.展开更多
本文研究了湿环境和预紧力对碳纤维增强复合材料单搭接螺栓连接结构拉伸性能的影响。通过吸湿试验、拉伸试验和有限元仿真,得到了以下主要结论:(1)施加预紧力对复合材料螺栓连接件的吸湿影响较小。(2)在预紧力从0 k N到2 kN的范围内,干...本文研究了湿环境和预紧力对碳纤维增强复合材料单搭接螺栓连接结构拉伸性能的影响。通过吸湿试验、拉伸试验和有限元仿真,得到了以下主要结论:(1)施加预紧力对复合材料螺栓连接件的吸湿影响较小。(2)在预紧力从0 k N到2 kN的范围内,干态和吸湿试件的结构强度均随预紧力增大而增大。(3)湿环境对结构应力分布影响较小。研究结果可为复合材料螺栓连接结构在湿环境中的应用提供支持。展开更多
文摘In order to solve the problem of surrounding rock control in soft coal seam roadway, taking the centralized return airway of No. 2 coal seam in Liangdu Coal Industry as the research background, the mechanical conditions of roadway surrounding rock were analyzed by means of field investigation, rock mechanics experiment and numerical simulation. The design principles of roadway support in soft coal seam were put forward: high strength anchor cable support, high preload support and high stiffness support. The bearing capacity of surrounding rock was strengthened by anchor cable support, and the deformation and failure of surrounding rock were effectively controlled. Through the numerical simulation method, the deformation and plastic failure range of roadwaysunder different support schemes are compared and analyzed. The support scheme of centralized transportation roadway is studied and determined, and the field test is carried out, which effectively controls the deformation of surrounding rock of roadway in weak coal seam.
基金Sponsored by the Pre-Research Foundation of Shenyang Aircraft Design and Research Institute,the Aviation Industry Corporation of China(Grant No.JH20128255)the National Defence Basic Research Program(Grant No.JZ20180032)the Pre-Research Foundation of Equipment Development Department of People’s Republic of China Central Military Commission(Grant No.ZJJSN20200001)。
文摘With the considerable applications of ceramic matrix composites(CMC) in aircraft engineering, the design of CMC bolted joint gains paramount attention because of its capacity to to improve load-bearing efficiency of aircraft key structure. In this work, a 3 D finite element model was established to predict tensile performance and failure modes of single-lap, single-bolt 2 D C/SiC composite, and superalloy joint, which considers the progressive damage behavior of 2 D woven C/SiC composites. On the basis of the developed progressive damage model, a parametric study was carried out to illustrate the effects of bolt preload and bolt-hole clearance on mechanical behaviors of the hybrid bolted joint. It was found that the increase in the value of bolt preload made the failure load grow first and then drop, and the optimum value of bolt preload 5.00 kN generated 56.47% rise in the initial failure load and 22.83% rise in the final failure load for the bolted joint in comparison with zero preload case. As the clearance increased from 0 to 2.00%, the initial and final failure loads respectively declined by 45.88% and 24.02% for 2.00% bolt-hole clearance relative to the neat-fit case. The loss in failure loads can be reduced to compressive stress concentration around the fastening hole-edge area, leading to the appearance of earlier damages by the introduction of increasing bolt hole clearance.
文摘本文研究了湿环境和预紧力对碳纤维增强复合材料单搭接螺栓连接结构拉伸性能的影响。通过吸湿试验、拉伸试验和有限元仿真,得到了以下主要结论:(1)施加预紧力对复合材料螺栓连接件的吸湿影响较小。(2)在预紧力从0 k N到2 kN的范围内,干态和吸湿试件的结构强度均随预紧力增大而增大。(3)湿环境对结构应力分布影响较小。研究结果可为复合材料螺栓连接结构在湿环境中的应用提供支持。
