Zhiqiang Huang

The fatigue behavior and fatigue reliability analysis of vibroseis baseplates based on fracture mechanics

Due to harsh working conditions and complicated external load, fatigue crack and fracture failure of the vibroseis baseplate usually occur during load cycles. To improve the fatigue resistance and extend the service life of the baseplates, this article studies the fatigue behavior of the baseplate materials and analyzes its fatigue reliability using fracture mechanics. Initially, the baseplate fatigue life is predicted by the crack propagation model based on the Paris’ and Forman’s laws. Three welded characteristic specimens of the baseplate are designed and fatigue is tested under a three-point bending load. The strain value and the crack propagation loading cycles are recorded during the test. Meanwhile, the crack propagation, damage, and fracture region of all the specimens are observed and tracked by scanning electron microscopy, which determines the fatigue damage mechanism of the baseplate. The fatigue reliability and parameter sensitivity analysis have been the subjects of previous research due to the randomness of the fatigue parameters. Finally, the most important random parameters are optimized based on the reliability analysis. As a result, the fatigue life reaches its maximum, and the reliability increases by 1.8%, resulting in a significant improvement in the fatigue resistance ability.

Geometry and force modeling, and mechanical properties study of polycrystalline diamond compact bit under wearing condition based on numerical analysis

Polycrystalline diamond compact bit has been used in more than 90% drilling length all over the world. Tooth wear is the main factor reducing the service life and performance of the polycrystalline diamond compact bit. In this article, the mechanical properties of polycrystalline diamond compact bit under wearing conditions are studied. The geometric model of the worn and unworn cutters is built. A numerical method to address the cutting parameters of cutters is first proposed. Then the effects of wearing degrees and the penetration per revolution of polycrystalline diamond compact bit on cutting parameters, forces, and wear conditions are discussed. The result shows that the numerical method can be utilized to obtain the force conditions of cutters, predict the wear trends of polycrystalline diamond compact bit, and optimize the cutter layout design. The effect of penetration per revolution on the mechanical properties of polycrystalline diamond compact bit and cutters is very limited. Under a constant penetration per revolution, the cutting section area almost keeps a constant with the increase of wearing degree; the direction of the transverse force keeps unchanged. The force conditions are closely related to cutting arc length and the wear degree.

Advanced Design for Vibroseis Truck's ROPS and Its Secure and Protective Performance Analyses Based on Dynamics Simulation Research

This research develops a design methodology for the vibroseis truck rollover protective structure (ROPS) and analyses its safety and protective performance with dynamics simulations. A new ROPS with the vertical anti-rolling over property is designed. For the typical field working conditions, we perform the stability study on the vibroseis truck and find its threshold function by using rollover dynamics. With the proposed protection and performance evaluation criteria, we analyse the protection performance of the new and old ROPS with finite element (FE) dynamics simulation. Then, the stress to strain, impact deformation, impact acceleration and interior energy distribution law are obtained during the process of the truck rolling over. The effect of the structure on its protective performance is also found. These analyses result in an optimal design of ROPS. The results will improve the safety of vibroseis trucks and then enhance the technology of oil and gas exploration equipment.