Applied Mechanics and Materials Vol. 577

Abstract: In order to be convenient for engineering calculations, the relative experiment was designed after analyzing the reasons why the adhesion force on the front wheel of the single vibratory road roller changes in the process of vibratory compaction. According to the result of the experiment, a concept of effective adhesion coefficient is put forward and a calculation method of it is provided. Draw a conclusion that the utilization rate of adhesion coefficient is highest in two gear and hope that it has a positive effect on the parameter design of vibratory roller and engineering applications.

Abstract: The concept of semi-active torsional vibration damper based on combined positive and negative stiffness is derived and its working principle is discussed. Stiffness expression of parallel mechanism is established, and its elastic properties were analyzed. By establishing nonlinear dynamic model of the proposed damper, its dynamic characteristics are analyzed. The torsional vibration control effect of the proposed damper is better than the traditional dual mass flywheel type torsional vibration damper.

Abstract: In the working process of numerically-controlled machine tool, the generation of heat by friction between the guide rail and the workbench will cause the thermal deformation under the high temperature, which impacts on the machining accuracy of machine tool. Through the finite element modeling for the guide rail of machine tool by the ANSYS software, the thermal characteristics is simulated in the process of guide rail, then the main factors of thermal deformation is analyzed, finally the corresponding measures focusing on the error compensation is proposed.

Abstract: In order to establish a three-dimensional model of the crankshaft piston group, the paper puts forward the application of feature modeling method. This method is that the designers extracting the Boolean operation directly from the feature library formed the design and definition of the part model. The paper analyzes the contact between the crankshaft features and its expression, using the Pro-E to build the feature model of crankshaft and the piston-connecting rod group which based on the 4JB1 diesel engine, forming a three-dimensional assembly drawing which provides the new ideas for the design and manufacturing personnel.

Abstract: Aimed at investigating time-frequency spectrum characteristic laws of conical pick rotary crushing coal and rock, this paper determines the mapping relationship of load spectrum between energy distribution and cutting process, and achieves quantitative reconstruction of the cutting coal and rock load spectrum. The experimental load spectrum is used as the object of research, utilizing wavelet regularization method to establish load spectrum reconstruction model of the pick cutting coal and rock, which will achieve its reconstruction load spectrum, so that it will discuss the variation of reconstruction load spectrum. Finally, it determines energy distribution of the load spectrum in different frequency band. The results show that the experimental load spectrum energy increases with the increasing of the cutting cycle number, and then decreases, so the characteristics of energy can characterize the cutting process. Energy of reconstruction load spectrum is mainly distributed in the low frequency range, which focuses on 1Hz and 3Hz, the amplitude of the high frequency energy is smaller than others.

Abstract: In this paper, we carried out some experiments of different structures of spiral grooved tubes on fouling characters, experimental results show the varying curve of the fouling resistance of the spiral grooved tube with time. We also imitate and analyze the variation of the resistance of the spiral grooved tube with the geometric parameters. The conclusion shows that the geometric parameters of spirally grooved tube have great effect on fouling, with increase the groove depth and decrease the screw pitch, the fouling resistance of the spirally grooved tube decrease accordingly. Large groove depth and small groove pitch is the best designed structure of spirally grooved tube.

Abstract: The paper proposes an analytical-numerical method for damping forced vibration problem of the rectangular stiffened plates with elastic boundary restraints. By enforcing applicable continuity conditions between plate and beams, coupled equations of beams-plate system are established. The displacement function is expressed as a modified two-dimensional Fourier series, which converts the differential equations of plate-beam systems into linear algebraic equations. Furthermore, Rayleigh’s proportional damping is introduced into beams-plate system so that damping parameters of stiffened plate can be inserted into vibration equations. It is derived that the present method demonstrates good agreement with standard finite element analysis. In subsequent analysis, it can be found that the boundary damping can reduce vibration energy of stiffened plate to same extent.

Abstract: For a new type of saw-milling composite work-head, using the finite element method and modal analysis tests to get the dynamic characteristics analysis of the system. We have made dynamic parameters analyses which are mode shape, natural frequency and damping ratio of the whole machine and the piece structure of work-head, and identified the weak links of the machine. The research shows that: the composite work-head’ weaknesses are in the sliding saddle joint, and the vibration instability trend would drive the whole machine; the dynamic stiffness of spindle is lower in the low frequency band, and it causes a certain influence on the machining accuracy.

Abstract: Based on WN gear characteristics and considering system error, a multi-degree-freedom (Tangential-Radial-Axial) dynamics analysis model after coupling friction was established. In this article, we established the three-dimensional solid model by using PROE and then imported WN gear’ three-dimensional model into Ansys software through the data interface of Ansys software and PROE software and conducted a three-dimensional simulation anasys of the impact of dynamic contact. By applying load, the stress analysis of WN gear was conducted and the WN gear’s the effective stress clouds was gotten. Meanwhile, basing on ANSYS / LS-DYNA, it established the rigid-flexible body of gear dynamic contact model and analyzed the dynamic simulation anasys of WN gear. The results demonstrated that the tangential and axial vibration of double arc gear was significantly greater than the radial vibration.

Abstract: The lateral longitudinal beam is one of the most important mechanical parts in secondary protection equipment of electrical power system. Basing on the simulation analysis platform of ANSYS Workbench, the standardization of the modular hole of the lateral longitudinal beam is studied in this research. The static and dynamic finite element analysis of the lateral longitudinal beam are used to obtain Von-Mises equivalent stress, deformation data, the natural frequency and vibration mode of five orders. The contrastive analysis of the results of finite element analysis provides a kind of theoretical instruction for the dimension selection of the modular hole.