Advanced Materials Research Vol. 842

Abstract: An estimation method to predict creep performances of high temperature structural materials has been proposed. A Stress relaxation equation is obtained by fitting stress relaxation testing curves and modifying Tanaka-Ohba reloading stress relaxation constitutive equation. Based on the relationship between stress relaxation and creep, a unified prediction equation of creep is deduced. The method is to use the unified equation to derive creep strain rates or creep strain vs. time curves from stress relaxation measurements through some specified time increments. In order to validate the approach, the predicted results are compared to the experimental results of uni-axial isothermal creep tests conducted on 1Cr10NiMoW2VNbN steel. Good agreement between results of creep tests and the predicted results indicates that the developed method can be recommended in the creep behavior evaluation of high temperature materials.

Abstract: In order to analyze the vibration performance of partially-filled liquid tank of ships, this paper takes the integration of measures including numerical simulation with finite element method and experimental verification with LMS vibration test and model analysis system of steel liquid tank under different liquid level conditions to study the fluid-structure interaction phenomenon. With the software of ADINA, the FEM model of the tank is developed and the model analysis which indicates the vibration modes and natural frequencies is completed. The simulation is compared with the experimental results which shows the natural frequency of the structure decreases with the level increases.

Abstract: This paper established a general mathematical modeling method based on stress analysis of the angular contact ball bearing under high rotation speed. The influence of the centrifugal force and gyroscopic moment generated in the rotation process is taken into account in this mathematical model. This paper conducted in-depth research for these aspects: the stiffness characteristics of angular contact ball bearings under different load conditions and different rotational speed, internal contact deformation and the change of bearing parameters.

Abstract: The influence of structure parameters on mechanical properties of honeycomb sandwich mirror was investigated. Gibson hexagon equivalent theory, sandwich plate theory and Hoff theory were modified based on the theoretical analysis. The results were shown that structure parameters had non-linear influence on dimensionless structure tensile specific stiffness, shearing specific stiffness and bending stiffness in different direction while the honeycomb core was equivalent as solid material with modified material properties. The honeycomb mirror and equivalent model was modeled by using finite element method. The root mean square (RMS) and peak-to-valley (PV) values of mirror surface were determined under gravity with the optical axis pointed to the zenith. Compared with the actual modeling data, the relative error of equivalent results was less than 5%. And the optimal structure parameter range was obtained by these analyses.

Abstract: In this paper, a ball mill gear reducer was regarded as the research object. Based on the HMM pattern recognition theory, DHMM methods that were used in fault diagnosis had been researched. The vibration signal was required a series transformations which are feature extraction, normalization, scalarization and quantization to get the sequence collections. Then the quantified sequence collections were trained to get the DHMM parameter, or the Viterbi Algorithm which was used for the quantified sequence collections to calculate the maximum probability, thereby the DHMM fault models library was established or the type of fault was recognized. Experiments of five kinds of fault model diagnosis were carried out in this article.

Abstract: Underground lifting compression processing station is the core equipment for domestic waste disposal. Compression equipment is the elementary equipment of underground lifting compression processing station and its mechanical properties will affect on compression effect of domestic waste. In order to analyze mechanical properties of compression equipment, the garbage curved surface shape function is established base on Eggshell theory, the load distribution of domestic waste inside compression box is studied, the density and load models of compressed domestic waste are established, and the load distribution function of compressed domestic waste for underground lifting compression processing station is deduced. Base on finite element method, the mechanical properties for compression equipment of underground lifting compression processing station is studied, which provides the basis for structure lightweight design.

Abstract: In the paper, a new transmission error design method for helical gears is presented. According to transition point position of the contact area in one meshing cycle, the proposed four-order transmission curve is able to diminish contact stress and edge contact, decrease transmission error as well. Tooth contact analysis is used to simulate contact conditions of helical gear driver with four-order parabolic modification curve. The results show that the meshing area is non-sensitive to the alignment errors.

Abstract: In order to get the optimal design scheme of a directly buried heating bent pipeline with many fold angles in a certain practical engineering, this paper simulated the pipeline by the ANSYS finite element analysis software.Through applying different boundary conditions to the model, the stress was analyzed, the destroy forms of the pipeline and the positions of stress danger points were determined,and the fatigue life was checked according to BS EN. Compared with the current design method,adopting numerical simulation analysis method has greatly reduced the number of the usage of compensators and fixed piers, broke through the restrictions for larger fold angle in the standard,and at the same time, it has reduced the construction difficulties and the engineering investment,improved the reliability of the network,this paper has guiding significance to the engineering practice.

Abstract: To make machining surface smoothing, a smoothing interpolation algorithm based on small line segments is proposed to meet the special requirements of smoothing machining. The algorithm takes the approach of s-curve acceleration and deceleration control for single tool path, yet between adjacent parallel trajectory adopts linear acceleration and deceleration control. This method enables feed rate between adjacent tool paths to transit continuously and meets the requirement of flexible and smooth machining. The article constructs a mathematical model of relationship among machining precision, maximum feed rate, acceleration, jerk and maximum allowable instantaneous feed rate to assure machining precision and machining efficiency. The model ensures that acceleration of single tool path and feed rate between parallel tool paths is continuous and simultaneously tries its best to enhance machining efficiency. In the end, the experiment result shows that the algorithm can meet the requirement of smoothing machining with an assurance of machining precision.

Abstract: In this paper, the sapphire crystal furnace is taken as the object of research. Based on the finite element analysis software ANSYS Workbench, static and modal analysis of the key parts of the crystal furnace are completed, the static and dynamic characteristics of the parts are studied, and the natural frequencies and the mode shapes of the key parts are obtained. According to the analysis of each mode type of the vibration, the weaknesses of the structure are identified, which provides theory reference for the structure optimization design of crystal furnace.