Applied Mechanics and Materials Vols. 184-185

Abstract: Torsion shaft is the important buffer and damping component of Self-Propelled Gun. Its main failure mode is fatigue fracture. In order to forecast the fatigue life of torsion shaft under stochastic loads, virtual prototyping of Self-Propelled Gun is established in Pro/E and ADAMS. A new kind of measurement method of load spectrums combining actual equipment experiment with virtual prototyping is firstly put forward in this paper and provides complete and accurate load spectrums of torsion shaft. Stress and strain spectrums can be obtained based on material’s S-N curve. The fatigue life of torsion shaft can be forecasted, which provide adequate reference for the maintenance cycle confirmation and mission reliability forecast.

Abstract: The vector and coordinate transformation method are applied to establish the constrain equations of the key points. Based on the existing data of suspension, applying the software CATIA, 3-D suspension model was established. The kinematic performance simulation of double-wishbone suspension model was calculated by setting the rational wheel-hop range. Based on the software MATLAB, the kinematics performance variation curves of the wheel alignment parameters were obtained, the variation laws were analyzed and the reasonableness of data were valuated.

Abstract: Calculation results are showing: There are basically specific relationships between loading machine’s weight and loading machines’ main parameters or other parameters’ combinations. So these specific relationships have certain similarity. And machine’s similarity criteria has invariance. The similarity equations derived from similarity theory basically coincide with quantitative analysis results from practical samples data. So, it is proved that there is a kind of similarity between loading machine’s practical design and development and similarity system’s design of structure size. So, the theory of simulation design is completely applied to practical design process.

Abstract: In this study, equations of the maximum bending stress (MBS) on the root of driving tine of the space-curve meshing-wheel (SCMW) are deduced. Four factors have an impact on stress concentration of the driving tines, the helix angle, the fillet, the diameter of driving tines and the radius of the spiral curve for driving tine. They have been studied by Finite Element Method (FEM). Results show the former two factors have great impact on stress concentration while the last two could be ignored. Then the method to gain the stress concentration factor is proposed. It makes the theoretical result of the MBS on the root of driving tine match the actual result.

Abstract: The paper established three-dimensional Computational fluid dynamic (CFD) model of the oil-air mixture in the gearbox after meshing by ICEM CFD simulated the turbulence model by the CFD. The method of calculate the windage power loss (WPL) of the spur gear were put forward. In order to reduced the WPL, compared the results between the CFD model with different modulus、clearance of the shroud and radius of the modification of gear top. The modulus is major parameter to WPL; the gear with shroud have lower WPL , WPL of the tooth flank and clearance of the tooth flank shroud do not show the proportional relationship, the gear with smallest clearance of gear side have lowest WPL，the modification of gear top can reduce the eddy scale which can reduce the WPL.

Abstract: The fluid flows and its related aerodynamic noise are very common in the nature and the engineering fieds. Lattice Boltzmann Method (LBM), which is based on the mesoscopic models, is a new CFD approach. It has the congenital superiority and the inestimable development potential in the simulation of complex fluid flow. Referring to the experimental results provided by NASA/CP 2004-212954, the aerodynamic noise produced by the flow through a cavity is simulated by the lattice Boltzmann method. The results had vividly demonstrated the shear layer oscillations, the couple between the shear layer oscillations and cavity resonance pattern. This simulation has discovered that the shear layer oscillation is the main reason for the production of cavity aerodynamic noise. The simulation results are consistent with the NASA experiment data.

Abstract: Abstract: In drilling process, drill pipes’ out surface always have lots of pits and scratches due to the corrosive and erosion of mud or wear of well wall in work environment. Through establishing drill pipe’s working model and constitutive equations with Finite Element Analysis Software, the paper have simulated stress distribution on drill pipe body under two different condition that without mechanical damage and with initial crack. Analysis results show that the maximum stress increases with the increasing of initial crack depth, and the maximum stress position turns to crack circumferential root from the crack radial root with the increasing of initial crack’s depth. The analysis result is completely consistent with the actual morphology of crack propagation, as a result, the simulation analysis provides a effective new methods and reference for remaining life assessment and failure analysis of drill pipe.

Abstract: Considering the large deformation of the hose pipe diameter caused by the pressure, this paper revises the hydraulic capacity on the basis of physical model of pipe-wall, establishes the mathematical model of the hose by lumped parameter model of pipe, builds the model of the system composed of the constant pressure oil source and flow valve using Simulink software and simulates the hydraulic impact by changing the pipe diameter and length. The established hose model and simulation results can provide reference for the related research.

Abstract: In this paper, the acoustic Helmholtz boundary integral equation is solved using Coiflet scaling functions with interpolation approximation property. The scaling functions are utilized as base and test functions in Galerkin method and the expanded coefficients are the values of the function in sampling points, so the number of numerical integral is reduced. Two numerical examples are given and the calculation results agree well with the theoretical results, which show the high accuracy of the estimation and demonstrate validity and applicability of the method.

Abstract: Based on a standard dual-equation turbulent flow model and coupled explicit solver,a wall function method was employed to closure the Reynolds averaged N-S equation .The mixing plane method was adopted to tranfer parameters between rotor and stator cascades. A approximate linear law is obtained in gas turbine cascade for supercharged marine boiler,which governs the variation of some parameters at the outlet of the turbine stage cascade along the blade height direction,such as pressure,velocity,as well as temperature and Ma.The results can provide guidelines for aerodynamic optimization design of the gas turbine stage cascade and the scientific management of this kind of set.