This paper proposes an effective genetic algorithm for the job-shop scheduling problem (JSP) to minimize makespan time. An effective chromosome representation based on real coding is used to conveniently represent a solution of the JSP, and different strategies for selection, crossover and mutation are adopted. Simulation experimental results have shown that the scheduling model using the algorithm can allocate jobs efficiently and effectively.
Isometric modification, as a new modification method of spur bevel gear was proposed. Based on the gear geometry theory and the normal meshing motion equation of gear pairs, changes of meshing points and angles are analyzed and the effect of axial modification on gear pair meshing movement is discussed, and then dynamics emulation analysis was operated with FEA software, the results show that the stress distribution of gear surface was controlled by isometric modification, the load concentration, agglutination and pitting of the gear can be avoided effectively.
The Ni-P-Sn coatings were prepared by electroless plating. Crystallization fouling adhering experiments indicated that these electroless Ni-P-Sn coatings have better anti-fouling property than that of un-coated and Ni-P samples. The surface free energy of Ni-P-Sn deposit increases with the increase of the nanocrystalline phase. It’s considered that the degree of crystallization fouling adhesion is related to the surface free energy of the sample. The amorphous matrix with lower surface free energy can significantly improve the anti-fouling ability in comparison with that of un-coated samples.
Based on the gear geometry theory and the normal meshing motion equation of gear pairs, changes of meshing points and angles are analyzed and the effect of tooth trace modification on gear pair meshing movement is discussed. It is concluded that chemical milling can effect tooth trace involute modification of fine-forged spur bevel gear, improve its surface quality and dimensional precision and therefore prolong its service life.
By modifying the profile of spur bevel gear,the load fluctuation in transmission process can be effectively reduced, the contact area of the gear pair can be greatly improved, and the stress distribution of gear teeth also can be controlled. However, during the actual work, many factors may influence gear work performance. This paper considers the influence of assembly error on contact performance of gear in mesh, builds the assembly error mathematical model of modified spur bevel gear, and deduces the parameter equation of modified tooth profile curve. Then dynamic contact simulation analysis is carried out by applying ANSYS/ LS-DYNA software, the distribution of the stress and strain of bevel gear pair in different shaft angle deviations is accurately obtained.
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