Advanced Materials Research Vols. 562-564

Abstract: In order to analysis the torsional vibration of crankshaft train in various assembly conditions, a 5S60 diesel model is presented based on AVL-EXCITE. A torsional vibration model is established by using the lumped mass method. And the deformation of main bearing is calculated under the bolt preload and outbreak of combustion. In addition to rated conditions, a state of one cylinder out of service is considered in this project. According to the calculation of the critical speed, torsion modes, angular displacement, shear stress in crankpin and minimum oil film thickness, the torsional vibration characteristics are analyzed. The study revealed that this system performs in good condition and the resonance is not obvious.

Abstract: To treat gear pair vibration due to internal excitation, an active internal gearbox structure near the gear pair is developed based on an active shaft transverse vibration control concept in the effort to tackle the gear excitation problem more directly. A controller of the FxLMS algorithm combined with frequency estimation technique is designed. And it is evaluated based on the experimental setup of the active gearbox vibration control system in contrast to fuzzy-PD controller. The experimental results show that 9.94dB attenuation in the gearbox housing vibration response can be achieved at the first gear mesh frequency by FxLMS controller, but only 5.62dB attenuation by fuzzy-PD controller. Besides, the insufficient effect at 210.8Hz and 216.2Hz is caused by typical out-of-band overshoot.

Abstract: In this paper, a model to simulate the dynamic behavior of the toroidal drive is developed. The three-dimensional dynamic model includes all six rigid body motions of the stator, worm, rotor and the planets. Using the model, the natural frequencies and vibration modes of the drive system are investigated. The vibration modes are classified into single modes and coupled modes. The single modes include planet mode, worm mode and stator mode. The vibration and frequency characteristics of different modes are obtained. The relation between modes and half cone angle of the planet tooth is discussed. The relation between vibrations and bearing stiffness is also discussed. When the bearing stiffness is about 10 times of the mesh stiffness, some vibration displacements of the drive system are quite small and can be neglected. Meanwhile, the dynamic equations for the drive system can be simplified.

Abstract: In the paper the process of a rigid particle penetrating into thermal refining steel and sliding on the surface is simulated by finite element method, the plough effect of sliding on contact surface and the adhesion effect of adhering to contact surface have be investigated. The apparent plastic flow and the material deposit are observed in the contact region, and the surface shape and the contact pressure distribution are obviously changed, the result of simulation is that surface deformation, contact pressure and friction shearing stress of contact surface depend on material mechanical properties, surface geometrical shapes and surface contact states. The mechanisms of plough effect and adhesion effect in friction are also studied, it is show that the mechanisms of adhesion effect and plough effect are different, plough effect is mainly crushing the surface layer in contact region, affected by material mechanical properties and surface shapes, and adhesion effect is mainly tearing the surface layer, affected by surface contact states.

Abstract: Assessment of spatial straightness error is one of the most difficult tasks in form error evaluation, especially when the minimum zone three-dimensional (3D) straightness is decided by four datapoints. This paper develops a solution that can transform the non-linear system into a linear system. To solve the linear indeterminate system of equations, a method of factor fixed is proposed. Given adequate initial conditions, this solution will be the exact solution. The effectiveness and efficiency of the novel approach are illustrated by two examples.

Abstract: In the analysis of the low speed diesel engine under bolts pre-tightening force, maximum explosion pressure, and piston group of reciprocating inertia force condition, the block main bearing hole values of stress and deformation, for the Mechanical stress analysis of the low speed diesel engine block. First, in the Hypermesh, use the hexahedral mesh near the main bearing hole, use the tetrahedral mesh in other parts. By setting up the grid unit density, control the mesh quality, densify the grid of key parts. And then calculated the stress and deformation of the block by use Abaqus. According the engine performance test data to set the boundary conditions. In the calculation of stress field, analyze the stress distribution and deformation of block under the bolt pre-tightening force, explosion pressure and reciprocating inertia force condition.

Abstract: Indirect inverse substructuring dynamic analysis has been developed recently by the author of this paper and provides a new simple approach to determine the coupling dynamic stiffness, which is one of important characteristics estimating dynamic quality of a mechanical product assembly. Based on a physical model consisting of “8-mass plus 16-spring and 8-damping” elements, this paper provides a set of validation on the completeness and effectiveness of the approach. Experimental verification is also carried out by use of eighty testing data of frequency response functions (FRFs).

Abstract: Indirect inverse substructuring dynamic analysis has been developed recently by the author of this paper and provides a new simple approach to identify the coupling dynamic stiffness of mechanical assemblies. To analyze the error effects of measuring frequency response fuctions (FRFs) on the identification, this study implements a set of parametric studies on basis of a lamped mass model to deal with parametric studies which result in some guidance for applications of the approach.

Abstract: In order to analyze the phenomenon of bolt preload when piston of low speed diesel engine is assembled and maximum explosion pressure and temperature during piston working impact on piston’s strength and fatigue life, Coupled analysis of mechanical stress and thermal stress on the piston of 5S60 low-speed diesel engine have been done, and the fatigue life of the piston on the alternating load condition was calculated. Firstly, the FEM-model which consists of 10-node tetrahedral meshes was built for the piston by using Hypermesh software with arranging different density of element quality which was guaranteed with the mesh parameters. Secondly, after setting the boundary conditions, the thermal stress, the mechanical stress and the coupling stress of the piston were calculated by using Abaqus software. Finally, the fatigue life of the piston on the alternating load condition was calculated by using nSoft software. The results indicate that the fatigue damage is easily occurred on the side of the surrounding area of the threaded holes, and that position should be made an especially consideration for design.

Abstract: Lemniscate floating crane is a patent product. There are great differences in outward appearance, geometric shape, luffing performance between lemniscate floating crane and ordinary double-link type crane. Lemniscate floating crane has some advantages, i.e. lower centre of weight, practical and reasonable structure, strongly anti-wind and easy operation. Based on inverse design principle, kinematics analysis of luffing mechanism of lemniscate floating crane is solved. The equations of kinematics are obtained. Luffing character of lemniscate floating crane is more better than ordinary double-link type crane.