【摘要】 基于应力强度因子知识，借助Workbench软件采用子模型技术和奇异单元研究搬运机械臂的断裂强度问题。在搬运机械臂基座关节相贯线处建立椭圆形表面裂纹有限元模型，开展抓取载荷、裂纹相对尺寸对应力强度因子影响的研究并进行裂纹扩展寿命计算。分析结果表明：K_Ⅰ、K_Ⅲ随着抓取载荷的增加而增加，而K_Ⅱ随着抓取载荷的增加而减小；随着裂纹短半轴和长半轴的增加，Ⅰ型、Ⅲ型应力强度因子先增大后减小且相应的应力强度因子逐渐增大，Ⅱ型应力强度因子先减小后增大；裂纹两端与中间段的裂纹扩展速率不同，呈现两端快、中间慢的特点且裂纹长半轴尺寸比短半轴尺寸对裂纹扩展速率的影响更敏感，机械臂的剩余寿命富余。更多还原

【Abstract】 Based on the knowledge of stress intensity factors, the fracture strength of handling robotic arm by sub-modeling technique and singular unit with the help of Workbench were studied. An elliptical surface crack finite element model was established at the coherent line of the base joint of the handling robotic arm, and the research on the influence of the gripping load and relative size of the crack on the stress intensity factor was carried out and the crack extended life calculation was carried out. It was obtained that: K_Ⅰ and K_Ⅲ increased with the increase of the gripping load, while K_Ⅱ decreased with the increase of the gripping load. With the increase of the short and long semi-axes of the crack, the stress intensity factor of Type Ⅰ and Type Ⅲ increased and then decreased and the corresponding stress intensity factor gradually increased, while that of Type Ⅱ decreased and then increased. The crack expansion rate of the crack at the two ends and in the middle section was different showing fast at both ends and fast at both ends, and the crack expansion rate was different showing fast at the two ends and fast at the middle section. Expansion rate is different between the two ends of the crack and the middle section, which is characterized by fast at both ends and slow in the middle, and the long half-axis size of the crack is more sensitive than the short half-axis size to the influence of crack expansion rate and the residual life surplus of the robotic arm is obtained. The analyzing and calculating method of the handling robot arm in the paper lays a theoretical foundation for the safe working of the handling robot arm, which has important guiding significance.更多还原