A study is carried out which analyzes the machinability of polymer matrix composites under an abrasive waterjet (AWJ) and the associated erosive process or mechanism. It shows that AWJ cutting can produce good quality...A study is carried out which analyzes the machinability of polymer matrix composites under an abrasive waterjet (AWJ) and the associated erosive process or mechanism. It shows that AWJ cutting can produce good quality kerf at high production rate if the cutting parameters are properly selected. A scanning electron microscopy (SEM) analysis of the cut surfaces reveals that the erosive process for the matrix material (resin) involves shearing and ploughing as well as intergranular cracking, while shearing is a dominant process for cutting the fibres in the upper cutting region but the fibers are mostly pulled out in the lower region.展开更多
Submerged abrasive waterjet peening(SAWJP)is an effective anti-fatigue manufacturing technology that is widely used to strengthen aeroengine components.This study investigated the correlation of SAWJP process paramete...Submerged abrasive waterjet peening(SAWJP)is an effective anti-fatigue manufacturing technology that is widely used to strengthen aeroengine components.This study investigated the correlation of SAWJP process parameters on surface integrity and fatigue life of titanium alloy TA19.SAWJP with different water pressures and standoff distances(SoDs)was conducted on the TA19 specimens.The surface integrity of the specimens before and after SAWJP with different process parameters was experimentally studied,including microstructure,surface roughness,microhardness,and compressive residual stress(CRS).Finally,fatigue tests of the specimens before and after SAWJP treatment with different process parameters were carried out at room temperature.The results highlighted that the fatigue life of the TA19 specimen can be increased by 5.46,5.98,and 6.28 times under relatively optimal process parameters,which is mainly due to the improved surface integrity of the specimen after SAWJP treatment.However,the fatigue life of specimens treated with improper process parameters is decreased by 0.55 to 0.69 times owing to the terrible surface roughness caused by the material erosion.This work verifies that SAWJP can effectively improve the surface integrity and fatigue life of workpieces,and reveals the relationship between process parameters,surface integrity,and fatigue life,which provides support for the promotion of SAWJP in the manufacturing fields.展开更多
为兼顾固体火箭发动机水射流清理工艺的安全性、高效性、环保性,在水射流清理实验和废水收集实验的基础上,以清理作业中推进剂质量损失速率、废水产生速率为优化目标,以射流压力、靶距、喷嘴直径、单次清理时间为变量并加以约束条件,建...为兼顾固体火箭发动机水射流清理工艺的安全性、高效性、环保性,在水射流清理实验和废水收集实验的基础上,以清理作业中推进剂质量损失速率、废水产生速率为优化目标,以射流压力、靶距、喷嘴直径、单次清理时间为变量并加以约束条件,建立了固体火箭发动机水射流清理工艺的多目标优化方法。利用代理模型技术建立了推进剂质量损失速率的代理计算模型和废水产生速率的理论计算模型,使用非支配排序遗传算法(NSGA-Ⅱ)求得了Pareto优化解集。该优化解集可为不同情况下的水射流清理工艺设计中推进剂质量损失速率和废水产生速率的匹配提供多种方案。用推进剂质量损失速率和废水产生速率的最佳匹配,由HTPB推进剂单位质量损失所造成的废水产生量仅为14.25 m L·g-1。展开更多
文摘A study is carried out which analyzes the machinability of polymer matrix composites under an abrasive waterjet (AWJ) and the associated erosive process or mechanism. It shows that AWJ cutting can produce good quality kerf at high production rate if the cutting parameters are properly selected. A scanning electron microscopy (SEM) analysis of the cut surfaces reveals that the erosive process for the matrix material (resin) involves shearing and ploughing as well as intergranular cracking, while shearing is a dominant process for cutting the fibres in the upper cutting region but the fibers are mostly pulled out in the lower region.
基金supported financially by the National Natural Science Foundation of China(Nos.52275148 and U21B2077)Natural Science Foundation of Shanghai(20ZR1415300)+1 种基金Innovation Program of Shanghai Municipal Education Commission(2019-01-07-00-02-E00068)Innovation Program Phase II of AECC Commercial Aircraft Engine Co.Ltd.(Grant No.HT-3RJC1053-2020)。
文摘Submerged abrasive waterjet peening(SAWJP)is an effective anti-fatigue manufacturing technology that is widely used to strengthen aeroengine components.This study investigated the correlation of SAWJP process parameters on surface integrity and fatigue life of titanium alloy TA19.SAWJP with different water pressures and standoff distances(SoDs)was conducted on the TA19 specimens.The surface integrity of the specimens before and after SAWJP with different process parameters was experimentally studied,including microstructure,surface roughness,microhardness,and compressive residual stress(CRS).Finally,fatigue tests of the specimens before and after SAWJP treatment with different process parameters were carried out at room temperature.The results highlighted that the fatigue life of the TA19 specimen can be increased by 5.46,5.98,and 6.28 times under relatively optimal process parameters,which is mainly due to the improved surface integrity of the specimen after SAWJP treatment.However,the fatigue life of specimens treated with improper process parameters is decreased by 0.55 to 0.69 times owing to the terrible surface roughness caused by the material erosion.This work verifies that SAWJP can effectively improve the surface integrity and fatigue life of workpieces,and reveals the relationship between process parameters,surface integrity,and fatigue life,which provides support for the promotion of SAWJP in the manufacturing fields.
文摘为兼顾固体火箭发动机水射流清理工艺的安全性、高效性、环保性,在水射流清理实验和废水收集实验的基础上,以清理作业中推进剂质量损失速率、废水产生速率为优化目标,以射流压力、靶距、喷嘴直径、单次清理时间为变量并加以约束条件,建立了固体火箭发动机水射流清理工艺的多目标优化方法。利用代理模型技术建立了推进剂质量损失速率的代理计算模型和废水产生速率的理论计算模型,使用非支配排序遗传算法(NSGA-Ⅱ)求得了Pareto优化解集。该优化解集可为不同情况下的水射流清理工艺设计中推进剂质量损失速率和废水产生速率的匹配提供多种方案。用推进剂质量损失速率和废水产生速率的最佳匹配,由HTPB推进剂单位质量损失所造成的废水产生量仅为14.25 m L·g-1。
