Applied Mechanics and Materials Vols. 215-216

Abstract: This paper deals with the research on method for the optimum equipment preventive maintenance strategy based on equipment reliability and equipment residual life in indirect condition monitoring. We use the Markov chain to express the equipment deterioration condition and propose the equipment reliability function; besides, study on the equipment condition probability distribution and establish the equipment residual life model by using the Bayes rule and the hidden Markov model, based on the above research background, we obtain the optimum maintenance decision criteria by analyzing the equipment maintenance strategy based on equipment reliability and equipment residual life in indirect monitoring. Finally, a case study is given to illustrate the implementation of the optimum maintenance decision criteria in indirect monitoring.

Abstract: This study developed a fatigue reliability method for evaluating and improving the key parts on railway vehicles, which was applied to real structures. The study involved a type of single-arm current collector, while its contact shoe often collapsed in operation and needs improvements. The dynamic stress data from the actual line was tested and converted to load spectra based on damage consistency rule, and then the fatigue life of the contact shoe structure was achieved. The calculation result comes to correspond to its operation life. Based on the method, an improving plan for the structure was developed under optimizing algorithms.

Abstract: This paper analyses the measurement demands of the mechanical-press ram displacement waveform on the sample frequency and displacement resolution. A virtual instruction system was developed that contains a USB2069 data acquisition card and a software based LabVIEW, and a Hall sensor sensitizes the displacement especially at the ram bottom dead center (BDC). The paper describes and explains the characteristic behaviors of the ram displacement curve on the macro shape and the micro waveforms of BDC in various shutheights. The discussion indicates that a flat bottom region of BDC waveform is due to the clearance between the transmission devices and the elastic distortion of the press frame, and the position of the punch backward departure is a steady inflexion point, which is the best BDC bottommost position. Based the time of flat BDC region, the clearance values can be calculated.

Abstract: This paper first analyzes the structure of can coiler to estimate the load of the internal bearing structure and then uses the Pro/e software to calculate the mass and centroid of the can coiler, in the same coordinate system to determine the load of the bearing. Next, the intensity of bearing under different conditions will be analyzed by using the ANSYS contact analysis module, from which the distribution of stress and size of extreme value can be observed. At last, the impact of load changes on the stress will be analyzed based on the comparison of the results.

Abstract: In this paper we establish a model of DVG850 machining center, and analysis the influence of bolts layout in the model on static stiffness. We got one hundred groups of stiffness data about different sizes of bolts through Workbench. Then the paper creates a 3D-graghs of different bolts, flanges and displacements, it also created a profile between flange-thickness and column-displacement. Though the dates and graphs it can find that stiffness of the hole machine will be influenced by the size of bolts and flanges directly ,also some better groups will shown in profile. Besides, relevant function is simulated by numerical methods. The conclusion provides a basis for the choice of better structure and can guide the analysis connection stiffness.

Abstract: In the condition of alternating impact ,the nut-supports subassembly is analyzed according to uncertainty of design parameters. Firstly, a three-dimensional (3-D) finite element (FE) model of the nut-supports subassembly is built and is meshed,and the constraints and loads are imposed.Secondly,the model of nut-supports was assembled using the software ANSYS to understand the stress distribution and various parts of the deformation of the nut-supports and its weak links in the harmonic forces.Finally,socket head cap screw has not enough pre-load in the condition of alternating impact and will be simplified.It is analyzed and checked whether it is cut or not; which provides the reference data for design and optimization of the wave maker.

Abstract: In order to get a reasonable working condition, using lumped parameter method and (Finite element method)FEM, a coupling dynamic model of the wind turbine gearbox is established. Analyze the natural characteristics and dynamic response in different conditions, and experiment study using operational modal test is carried out. Comparing the experimental data with the FEM result, vibration of the gear box in the rated power condition is the most stable, while vibration becomes violent when overload, it matches well with the other one, it is verified that the model is reasonable. This paper provides theory support for wind turbine gearbox design and analyze.

Abstract: Aiming at the actual cold bending forming rolling process, in order to make more accurate analyses to stress and strain, the paper mentioned dynamic link model of rolling process, and based on the spline finite method , using the model to study the deformation analysis method of node and link in actual roll forming process, giving the holey stress and strain mathematics description type of link structure node, and on this basis intelligent node structure is given. Set up corresponding Agent for each node or link, establish knowledge rules for each Agent, realize a new method making use of link model to analysis cold bending forming. Provide the theoretical foundation of establishing a new complex profile groove design algorithm.

Abstract: Based on the practical working state and load conditions of a car, the stress-strain and its strength in static and dynamic state of a new torsional vibration damper were calculated and analyzed with the finite element theory and tools, providing reliable data and a simple and accurate research method of strength for its practical application.Through strength analysis, the maximum equivalent stress of main parts of damper under static load and the stress time curve under dynamic load were obtained. By comparing the analytical results under static and dynamic load, it shows that all parts of the damper meet the strength requirements under the dynamic load, and that the maximum stress value of main parts under idle speed conditions is higher than that of running conditions, which is consistent with the actual working condition; while under the static load, the rivets did not meet the strength requirement. In conclusion, two feasible methods were proposed to improve the strength of rivets. It is verified that this damper can meet working strength requirements at last.

Abstract: Based on reliability optimization design theory and sub step optimization method, the mathematical models of transmission ratio distribution and gears’ parameters are established, respectively. In the model, the normal module, pressure angle, the teeth width, teeth number and modification coefficient of the gears are taken as design variables, while the volumes of the yaw reducer and single stage transmission are taken as the objective functions. Then the complex optimal problems are solved using two heuristic optimization algorithms. Compared to the original design, the volume of the yaw reducer decreased by about 3.5% under the premise of maintaining the strength requirements and ensuring high reliability, which supplies an effective approach to further developing the reliability optimization design of multi-stage planetary gear systems.