Applied Mechanics and Materials Vols. 184-185

Abstract: For accurate simulation of the casting process with permanent mold, the correct Interfacial Heat Transfer Coefficient (IHTC) is highly important. However, its value is not easily obtained through the experimental or theoretical method in the complex solidification process. In this paper, an inverse conduction model is introduced to determine the IHTC at casting-mold during solidification of the cylindrical casting based on the temperature-measured data. The established inverse model is verified to be a feasible and effective tool for estimation of the metal-mold IHTC during solidification of cylindrical casting by the analysis of calculated results.

Abstract: Though air spring greatly improves the isolation efficiency of raft isolation system, the technological problem occurs as how to maintain raft attitude balance. This paper set up an analysis model of raft attitude disturbance, and analyzed the influence of various disturbance sources on raft attitude, including hull rolling, systematic load variation, and air spring leakage. It proposed to control raft attitude through adjusting the pressure of air spring isolator, and then studied the feasibility of this method. The results show that the influence of various disturbance sources could be canceled effectively by adjusting the pressure of air spring isolator, thus maintaining attitude balance.

Abstract: To establish accurate models for powertrain optimization of a Chinese sport utility vehicle Landwind X8, a powerful CAE tool GT-Drive was used to evaluate the vehicle drivability and fuel economy. Various proper models were established and vehicle performance was simulated, obtained results show that drivability of the vehicle is satisfactory in a macro sense, but fuel economy is moderate. Further comparison of simulated performance indices with field test data demonstrates that nearly 80% of the absolute relative errors are below 5%, the maximum absolute relative error is also less than 10%. Thus, the simulated data met well with the test data, it is confirmed that the established simulation models are validated and can be used as effective analysis tools in further powertrain optimization.

Abstract: In the process of strength and fatigue reliability research of breech, finite element model of breech was established with the finite element software ABAQUS. Then the maximum stress of breech in the recoil process was obtained through FEM dynamic analysis, and the calculated results indicated that the breech strength design met the requirement. Take dynamic stress course as the load spectrum for fatigue life prediction of breech in fatigue analysis software. The study provides a useful reference for breech design and optimization.

Abstract: Rotary Piston Engine is a new kind of rotary engine. To analyze the dynamic character of the valve system, kinematics equations are established using dynamical method. Dynamic response of the valve is studied by calculating the outcome using numerical method.FFT analysis is applied here to analyze the response curve. The result shows that the Valve Train covers the basic need, but the dynamic performance of the system still could be improved.

Abstract: In the process of automated riveting, the position between the riveting head and the holes distributed on the stringer and wing skin to be riveted will go beyond the design requirements currently. Using the edge distance determination technology to measure and compensate the deviation in time is one effective method to solve this problem. In the dissertation, after the characteristic of the edge distance determination technology is introduced, the working principle of the edge distance tracer apparatus is developed. Based on the mechanical design solution, a pressure sensor is selected to measure the position relationship between the riveting head and the stringer. Then an edge distance tracer apparatus is struck out to detect the deviation, which is an automatic positioning feedback device that can be fit for many kinds of stringers. And the riveting head is operated to meet the design deviation requirements. By using this technology, the drilling precision of the automated riveting system can be effectively improved.

Abstract: The three dimensional model was established for studying performance of spiral groove gas face seal. According to machining features of different surface area, the seal face can be divided into three parts, rotor ring grooved area, rotor ring non-grooved area and static ring area. The effect of roughness on seal performance was analyzed based on calculation of three dimensional flow field. The analysis results show that the surface roughness of rotor ring grooved area has great influence on the seal performance, but the influence is little when roughness on non-grooved rotor ring surface and static ring surface. The influence must be considered when surface roughness of rotor ring grooved area bigger than 0.2μm. Roughness of rotor ring surface can increase the loading force while it also can cause the increase of leakage. It is important to select rational roughness when designing gas face seal.

Abstract: A numerical model for conjugate heat transfer (CHT) simulation is established for a turbine blade with air cooling, and 3D heat transfer simulation is accomplished. Effects of different amount of cooling air on the surface temperature distribution, work, efficiency of turbine blade is studied. The results show that the surface temperature drops quickly with the increase of cooling air at beginning and then become mild, the blade work goes up, the efficiency goes down.

Abstract: Conventional drive wheel strength check is based on Hertz line contact theory to do the calculation, for security reasons, the design is more conservative,so that there is a certain margin in carrying capacity of the wheel. To address the above issues, this paper analyzes the wheel contact problem for a precise non-linear contact by the finite element method. By comparison of two methods, it verifies that using the finite element is reasonable to deal with these issues, while it provides a reference for the rational design of full load capacity wheels as well.

Abstract: The larger bending velocity is needed in practice to improve efficiency of tube bending, however, whether it has undesired effects on bending behavior has not been identified and clarified. In this study, taking thin-walled 6061-T4 Al-alloy tube of Φ50.8×0.889×101.6mm (out diameter D×wall thickness t×bending radius R) as the objective, the physical experiments are carried out to explore the influence rules of the bending velocity on tube bending in terms of major defects such as wall thinning, wrinkling and springback. The results show that: 1) both higher and lower bending velocities result in excessive wall thinning and wrinkling. 2) springback angle increases with increasing of bending velocity.