To solve the contradiction between high quality and high efficiency of CFRP machining surface, the quadratic regression models of 3D surface roughness Sa and surface damage layer depth Dd were established by using the response surface method, and the genetic algorithm was used for multi-objective optimization to obtain small Sa, Dd and maximum material removal rate VMRR. The results show that the regression models of Sa and Dd are explicit and reliable, and the feed speed vf has the most significant influence on Sa and Dd, followed by the grinding depth ap, the spindle speed n and the ultrasonic amplitude A. The results of response surface analysis show that the interactions of n and A, vf and ap, vf and A have significant effects on Sa. The interactions of n and A, vf and A, vf and ap, ap and A have significant effects on Dd. When the weight ratios of Sa, Dd and VMRR are 1/5, 1/5 and 3/5 respectively, compared with the central point results, the optimized Sa decreases by 11.01%, Dd decreases by 10.08%, and VMRR increases by 62.02%. The absolute values of the relative errors between the experimental and the predicted values of Sa and Dd under the optimized process parameters are 8.25% and 9.41% respectively, indicating that the prediction model has high accuracy and can be used for the optimization and prediction of the process parameters of CRFP ultrasonic vibration grinding.

为分析碳纤维增强树脂基复合材料(CFRP)/钛合金(TC4)叠层材料低频振动制孔工艺下刀具磨损状态,开展基于切削力信号的制孔刀具磨损状态研究.通过采集CFRP/TC4叠层材料低频振动制孔过程中的切削力信号,进行时域和频域分析,探讨各信号特征量与刀具磨损状态之间的联系.研究结果表明:CFRP/TC4叠层材料低频振动制孔轴向力信号的均值、标准差、方均根和峰度系数都与刀具磨损状态关系密切.轴向力信号频率主要集中在0 Hz、主轴旋转频率33 Hz及振动刀柄振动频率38 Hz处,且频率分布不会随着刀具的磨损而改变.

碳纤维复合材料内部结构的健康程度将直接影响到零部件的整体性能.采用高频超声衰减法对碳纤维复合材料进行内部无损检测.在超声波频率为30 MHz、探头距离工件表面1 cm、等离子水介质条件下,通过超声C扫描、X扫描,分析和确定内部缺陷位置及形状,并通过剖切试样,采用光学显微形貌表征对内部缺陷进行确证.采用ABAQUS对层间缺陷的力学性能影响规律进行仿真.结果表明:不同缺陷尺寸、不同温度条件对材料断裂强度的影响规律不同.

为研究铣削参数对复合材料力学性能的影响,开展了以主轴转速与进给量2个变量为试验因素的全因素铣削加工试验,并统计分析了不同加工参数下复合材料试样的拉伸性能及压缩性能.试验结果表明:复合材料的拉伸性能和铣削加工参数无关,而压缩性能随着主轴转速的提高而降低,与进给量无关.同时,不同加工条件下的拉伸及压缩测试断口形貌表明,过高的主轴转速会造成加工区域基体的热损伤,分析认为这是造成材料压缩性能下降的原因.

Based on the concept of effective abrasive grain number and the calculation method of surface roughness, two indexes, namely effective dressing rate Nr and dressing dispersion degree H, were proposed to evaluate the grinding performance and surface topography of the grinding head. The variation of Nr and H during the dressing process were analyzed. The relationship between both indexes and the surface roughness and the grinding force of carbon fiber reinforced plastics(CFRP) after grinding was also established. The experimental results show that Nr can effectively characterize the dressing state of the abrasive particles on the grinding head and reflect the passivation degree of the grinding head. H can effectively characterize the contour of the abrasive grain, and predict the quality of CFRP surface. When H is 18~25 μm, the grinding head surface roughness is the best. The grinding head force has smaller growth amplitude, and the grinding head has better performance.