断裂面缺损定量分析及其对连杆强度的影响

借助连杆裂解实验获得断裂接合面,利用逆向工程重构断裂面,建立带缺损的连杆模型,实现连杆断裂面缺损定量描述.探究不同尺寸、不同位置的缺损对连杆强度的影响,以此为依据制定加工中相关技术标准.通过模拟得出:随缺损尺寸增加,连杆承受的应力逐渐增加,连杆强度降低.缺损面积越大,其对连杆应力的影响越显著.同尺寸缺损当其位于接合面内部时,连杆的等效应力大于其位于接合面边缘,即内部缺损带来的危害高于边缘缺损.为保证连杆强度,缺损尺寸应满足:边缘缺损,当1.5mm＜b＜2.5mm时,a≤-1.125b+5.0875;面内缺损,当1.4mm＜b＜2.1mm时,a≤-1.143b+4.8.

Quantitative Analysis of Fracture Surface Defect and Its Effect on Strength of Connecting Rod

The fracture joint surface was obtained by the fracture-split test and the fracture surface was reconstructed by reverse engineering. The connecting rod model with defect was built. The quantitative description of the fracture surface defect was realized. The effects of fracture surface defect of different sizes and positions on the strength of the connecting rod were explored, and the control standard of the relevant dimension in the processing process was formulated. The rules were obtained: with the defect size increasing, the stress of the connecting rod increases gradually and the strength of the connecting rod decreases. When the defect area is larger, the influence on the stress of the connecting rod becomes more significant. The stress of the connecting rod is greater when defect is inside the joint surface than that at the edge of the joint surface. In order to ensure the strength of the connecting rod, the defect size should meet: defect on edge, when 1.5mm＜b＜2.5mm, a≤-1.125b+5.0875; in-plane defect, when 1.4mm＜b＜2.1mm, a≤-1.143b+4.8.