Papers by Author: Shen Hua Yang

Abstract: The effect of starting notch machining methods on fracture splitting of connecting rod was studied by axial tensile tests with single edge notch. The axial tensile specimens were made of the high carbon microalloyed steel (C70S6) which is now most widely used by the connecting rod of fracture splitting. The single edge notch of axial tensile specimens were respectively machined by laser notch、wire cut electrical discharge and broaching. The notch tip plastic deformation of specimens was compared by the fractography. The experimental results indicate that the specimens with laser notch can be fractured by the smallest axial tensile load which is respectively about 20% and 30% smaller than the fracture load of the specimens by wire cut electrical discharge and broaching. Considering the rich micro-local crack transformation hardened zones around the notch by laser the paper present the equivalent critical stress intensity factor KIcL which can be used to calculate the fracture load with laser notch.

Abstract: The fracture splitting (FS) method is a bran-new processing technique in the automobile engine connecting rod manufacturing industry, FS is one of three pivotal working procedures, and press speed is one of the key influence factors of FS process. In order to realize parameters of press speed and pull cylinder working pressure, dynamic simulation of hydraulic system has been carried out. Simulation results indicated that press speed of pull cylinder was about 130mm/s, which was between 120mm/s and 150mm/s that was not only good for controlling FS quality, but also not leading irrational design of hydraulic system. The working pressure of pull cylinder was between 10MPa and 14MPa, which was suitable for FS processing. The hydraulic system of FS machine can satisfy the basic requirements of connecting rods FS process. This paper has provided reliable theoretic basis for the design of FS machine for connecting rods.

Abstract: Splitting force is the key to the process of fracture splitting connecting rod. In this paper, numerical simulation is made in the process of fracture splitting Jetta car connecting rod by using software MSC.MARC. Through analysis, the curve between J integral and splitting force is established. According to the experiential formula of impact toughness and fracture toughness, critical J integral ( JIC ) can be achieved. After getting JIC , the splitting force can be determined by linear interpolation method and verified by tensile experiment and the error is below 1%. It is proved that this method can also used to analyze other kinds of connecting rods with different materials.