Applied Mechanics and Materials Vol. 344

Abstract: To meet the demand of wear-life calculation of spherical plain bearing (SPB), the wear-life models for angular contact spherical plain bearing (ACSPB) under different types of load were created based on the joint wear calculation method (JWCM). By integrating the friction wear laws of materials, specific configuration & mating characteristics of the SPB, and function requirement, the new models were more theoretical and had a good applicability and pertinence compared to the empirical models used at present.

Abstract: There is very important practical significance for borehole stability to oil and gas drilling and production. When the mud density is too large (mud column pressure too high),the formation will be fractured. When the the mud density is too low (mud column pressure too low), the borehole wall will be collapsed, and hole will be enlarged. In this paper, the fracture pressures of the formations were determined by using the maximum tensile stress theory. The formation collapse pressures were determined by using the Coulomb - Moore intensity criteria. According to the fracture pressure and collapse pressure to evaluate the borehole stability. The two wells stability evaluation examples were given, and the borehole security mud window were calculated.

Abstract: Due to the special hull shape of the catamaran planing vessel, the shiplines optimization design and the hydrodynamic performance prediction of the catamaran planing vessel are mainly carried out by model tank tests and the empirical formula at present. The numerical prediction method of the hydrodynamic performance of catamaran planing vessel has been a big difficulty for a long time. In this paper, the influence of the key channel design parameters on the catamaran planing vessel hydrodynamic performance is studied based on the CFD technology. Some beneficial conclusions are obtained which is helpful for the optimization design of catamaran planing vessel. The work of this paper provides a numerical research method for the optimization design of the catamaran planing vessels hull.

Abstract: The classical approaches using CFD software to calculate the hydrodynamic performance of catamaran planing vessel still need to rely on the model test or empirical formula to make sure of the running attitude. So a theoretical calculate method of resistance performance of catamaran planing vessel is proposed in this paper based on RANS equations and the VOF method to couple six degrees of freedom equation of the catamaran planing vessel. Numerical simulation results indicate that using RANS equations can better forecast hydrodynamic performance of catamaran planing vessel at high speed, which provides a practicable numerical method for optimization design of the catamaran planing vessels hull.

Abstract: The forming behavior of Al-Si coating on magnesium alloy fabricated by supersonic particles deposition was investigated by numerical stimulation. The results indicated that the later deposited particles generated horizontal spread effect at interface and interlocked mechanically with metal jet produced by the former deposited particles, which promoted the formation of mechanical bonding of Al-Si coating. Temperature of deposited particles at bottom of Al-Si coating was higher obviously than that on the top layer, the maximum value was about 498°C at the collision contacting points among deposited particles at bottom of the coating, which would promote metallic bonding and physical bonding, proved that magnesium alloy and Al-Si particles were matched pair suited for supersonic particles deposition.

Abstract: In order to easy use Green function on cloud computation, the author consider control equation of point source with free surface, and discuss the representation of Green function on cloud computation, and then propose the discrete calculation expression as well as the calculation procedure. Finally, the two-dimensional graphics of the Green functions real and imaginary parts are plotted.

Abstract: Liquid nitrogen engine is a new type of cryogenic engine with zero discharge. In order to gain a better understanding of the cylinder flow field, we simulate the velocity field and turbulent kinetic energy field of the cylinder, and the relationship between pressure and the crank angle in different intake pressure by using STAR-CD in this paper. The simulation results are compared with experimental results.

Abstract: On the basis of Coordinate transformation analysis of the inertia parameters in three-dimensional space, according to the characteristic that the coordinate direction is existed and unique which the product of inertia is 0 when rotating the coordinate system, a new method to judge and calculate the particle information by searching for the intersection of the two lines that lead from two different coordinate origin is proposed. The processes and procedures to calculate the internal mass of rigid body are deduced theoretically. A special numerical example is given to verify the correctness of the theory. The error factors are analyzed qualitatively as well.

Abstract: A method is put forward that is to use anisotropic virtual material to simulate the characteristic of combined parts to analyze the dynamic features of crank connecting rod mechanism, that is when entering material parameters, different directions have different value, so it can simulate combined stiffness of every directions, and it will also simulate the relative movement relationship of components effectively. Through the analysis of three group of different value of anisotropic virtual material, drawing the conclusion that it is feasible that use anisotropic virtual material to simulate the characteristic of combined structures. The method is a breakthrough in analysis of dynamic characteristic of combined structure. The virtual material method is different from traditional virtual material method in this paper.