Applied Mechanics and Materials Vols. 80-81

Abstract: Numerical simulation was made on parameters like internal pressure and axial force as well as friction coefficient of tube that affect the formation of variable cross-section tube. Through numerical simulation and orthogonal optimization, the most thickness reduction ratio and thickness uniformity on different conditions were contrasted and analyzed. An optimum scheme was obtained and it could improve the formability of variable cross-section tube. The result indicates that the axial force plays the most important role on thickness reduction ratio. The result provides technical support for the variable cross-section tube hydroforming research.

Abstract: As one of the best ways to lightweight car-white-body, tailor rolling blanks (TRB) are affected by various factors when produced, such as friction, rotational speed of working rolls, adjusting speed of rollers gap, rolling force, roller stiffness, etc. In this paper, a three-level three factors orthogonal table was set up and various tests were simulated by using orthogonal design method and Deform-3D software. Take the comparison of simulated curve with the target curve as experimental index, one set of optimal rolling parameters was found by variance analysis to the experiment results. This researching results can provide technical support for production of TRB, and promote the TRB application in the car lightweight.

Abstract: Radial runout is a major performance parameter of running accuracy of bearings. In order to increase the running accuracy of cylindrical roller bearings, a new algorithm is presented. Firstly, the principle of program is researched under some suitable conditions. Secondly, the process and structure of program is described in detail. In the end, the influence of the size of roundness error on the radial runout of bearings is researched. The results show that the radial runout increases 7 times higher with the increase of roundness error size of outer ring.

Abstract: Compression experiments of spruce along axial, radial and tangential loading directions are implemented by INSTRON equipment. Mechanical properties of spruce along three directions are gained. Spruce microscopic cell failure modes under axial, radial and tangential compression condition are observed by scan electron microscope. Results show that failure modes of spruce are fiber buckling and wrinkle when loading direction is along the grain. When loading direction is along radial or tangential across to the grain, failure modes are wood fiber slippage and delamination. Theory analytic solution to single wood cell failure under different direction compression is done. The obtained expression shows that mean limit loading is relative to yield stress, cell structure dimension and wrinkle length for complete wrinkle cases.

Abstract: We analyses the instance that the retaining ring is near to the top, adopt the theory of the axis symmetry column thin shell, and construct a displacement function, then work out the analytical solution of the residual stress under this instance.

Abstract: Along with rapid development of high-speed railway in many countries, recently research on seismic response of high-speed railway bridge under train load has raised much concern among researchers. The whole bridge finite element model is establish to analysis the seismic responses of simply-supported girder railway bridge subjected to high-speed train in this paper, ICE series high speed vehicle is employed as train live load, the vehicle is simulated by moving spring-mass system, The track irregularities can be obtained by Simpack software, the birdge incluing superstructure and substructure is three-dimensional space beam element, the bottom of piers is proposed consolidated. elastic seismic responses of bridge system and elastic-plastic deformation of piers considering different train speeds are calculated. The calculation results indicate that, seismic responses of bridge system are increase with the increase of train speed and earthquake intensity, and the bottom of piers will step into elastic-plasticity stage under high-level earthquake, the plastic hinges occurred within 1.4 meters of bottom of pier. The numerical results can provide some references for design of high-speed railway bridge.

Abstract: Crack monitoring is thought to be a challenging problem for structural health monitoring. In previous study, a bionic crack monitoring method is proposed to monitor the crack initiation and propagation in a structure, and smart film is designed and fabricated. A novel design, based on smart film for monitoring crack width of concrete structures, is proposed in this paper. Experiment verifies the effectiveness of this design, and proves it is a good way for crack width monitoring of concrete structures.

Abstract: The continuum/discontinuum multiscale analytical system of the interaction between rigid wheel and lunar soil by coupling discrete elements and matrix module was established. The DEM parameter of lunar soil particles was confirmed by the biax-test. The mesoscopic dynamic behaviors of lunar soil simulant subjected to rigid lugged wheel with different structures were simulanted and analysized by the multiscale method. Comparing the simulation results with the soil-bin test results, the multiscale model not only satisfied the computation accuracy, but also had the much higher computation efficiency.

Abstract: The simulation system between smooth rigid wheel and lunar soil by Discrete Element Method (DEM) was established and validated. Three section structures of smooth rigid wheel, including flat, concave and convex structures were designed. The effects of these three different wheel section structures on dynamic mechanical behaviors of lunar soil simulant were simulated by PFC2D^®. The simulation results indicated that the concave section structure of smooth rigid wheel has the best anti-sinkage ability, the convex section structure has the good anti-sinkage ability, and the flat section structure has the worst anti-sinkage ability.

Abstract: The analytical solutions for the deformations of straight-ends in three-roll bending process of thin-plate were presented. Based on the theoretical analysis on the loading and unloading during roll-bending, the curvature equations governing the bending behavior of thin-plate were set up and then solved by integration. Numerical examples were given to illustrate the application of the solutions. The curvature and deflection distributions on straight-ends were shown in graphically and discussed.