Key Engineering Materials Vol. 667

Abstract: The traditional electric heating device mainly used resistance wire as the electric vehicle components. A novel semiconductor nanoelectrothermal film as a heating material was to study its feasibility. By analyzing the heating mechanism of electrothermal film and comparing the existing heating device, an energy-saving heater was designed based on semiconductor nanoelectrothermal film. In STC89C52 micro-controller core, a practical and stable temperature control system was devised by a variety of control methods - shock control, relay control, pressure control, and so on. The energy consumption experiments were done between new electric heating device and conventional heater, and the results showed that new electric heating device had more energy efficient. On the basis of this study, a series of electric heating products could be developed with low power and environmental protection, and it was a useful exploration for technology upgrades for the electric heating industry.

Abstract: Reverse design based on CMM (Coordinate Measuring Machine) measuring has been used in the engineering design widely because of its higher quality, shorter manufacturing cycle and lower cost. The flexible rod is widely used in tension mechanism because of its large adjustable range, high tensile strength and good flexibility. The reverse design of a flexible rod based on CMM measuring is researched in this paper. The structure of the flexible rod was analyzed. The CMM digital measuring of the part has been completed and the data of measuring results is processed. The reverse 3D modeling and design of the flexible rod have been accomplished.

Abstract: In order to obtain the pinion's natural frequencies and mode shapes of a new kind of spiral bevel gear (SBG) which is logarithmic spiral bevel gear (LSBG) in the unconstrained state for the purpose of dynamic characteristics study, select the low carbon alloy steel 20CrMnTi (China specification) with good mechanical properties, which the carbon content is 0.17%-0.23%, the elastic modulus E=2.06675×10¹¹Pa, the Poisson's ratio is 0.25, and the density is 7.85×10³kg/m³, the finite element model of LSBG pinion which consist of 35100 nodes, 19889 Solid187 tetrahedron FEM elements is established by using free meshing method based on LSBG pinion's physical model in this paper. Solve the modal parameters of the first 6 orders, draw the main vibration mode shape according to the first 6 orders natural frequencies respectively. The first 6 orders critical revolution speeds are calculated by the first 6 orders corresponding natural frequencies, and the LSBG pinion allowable work revolution speeds are 117074.16 revolutions per minute. The free modal analysis of the conventional SBG pinion with the same parameters is done for comparison with LSBG pinion. The results show the LSBG pinion's nature frequency and the critical revolution speed are both lower than that of conventional SBG. The conclusions reflect the vibration response characteristics of LSBG pinion, and provide theoretical basis for dynamic response, structure design and optimization of LSBG pinion.

Abstract: Partial load has great impact on both service life and security design of scissor transmission mechanism. A mechanical model has been established, on the assumption that the scissor units are rigid bodies and the connecting rods are elastic bodies, for the research on the scissor transmission mechanism considering partial load. The recursive matrix used to calculate the node force of multi-unit transmission mechanism has been obtained. And based on the recursive matrix, the method has been deduced to calculate the node force of the scissor transmission mechanism in the unbalanced loading condition after the connecting rods were replaced by equivalent models—the springs. The finite element model carried out with SAP84 was established to measure the accuracy of the equations obtained by theory derivation, and the results proved the correctness of the theoretical formula because of the little difference between theoretical results and simulation results. The conclusion obtained could serve as theoretical guidance for mechanical analysis and optimal design on scissor transmission mechanism in the unbalanced loading condition and reference for elastomeric scissor unit research.

Abstract: This paper takes the ultra-high pressure (103.5MPa) valve body as the research object and adopts the finite element method to perform simulation analysis on the three bearing conditions involved with the valve body, i.e., autofrettage pressure, discharge and working pressure. The simulation shows identical results with the theoretical calculation. The relationship between the maximum equivalent stress and autofrettage pressure during the operation of the valve is obtained from the simulation results; therefore the best autofrettage pressure is determined. When determining the maximum value of autofrettage pressure, the maximum pressure, at which reverse yield does not happen, and the complete yield pressure shall be taken into consideration, with the smaller value of the two taken after comparison and analysis. When the size of the valve body is fixed at certain value, the best autofrettage pressure is not a fixed value, but it varies with the change of working pressure.

Abstract: For improving braking efficiency, the high friction composite brake shoe, instead of cast-iron shoe, is widely used in railway wagon. However, some flange and tread of the foundation brake rigging wear frequently in operation, leading to the over standard of wheel diameter difference, which affects the safety performance and the running efficiency of railway transport. This paper uses the normal pressure between wheels and shoes as the evaluation index of tread wear and the lateral shift of brake beam as the evaluation index of flange wear. With the multi-body dynamics simulation method, take a research on the influence of curve braking for flange and tread wear. Firstly, establish a multi-rigid body dynamics model of the foundation brake rigging in RecurDyn software. And then, take a research on the lateral shift of brake beam and the pressure distribution of shoes for empty and loaded wagon on four kinds of curves braking respectively. At last, to testify the simulation results theoretically, analytical method is used to derive lateral force of the brake beam. The results indicate that the lateral shift of rear brake beam which lead the shoe moving close to the flange is the cause of flange wear, and the positive pressure between wheel and shoe of one wheel-order bigger than others is the cause of tread wear. The research accomplishments above provide technical support for further improvement of the foundation brake rigging in railway wagons.

Abstract: Based on MSC. DYTRAN, the platform of virtual artillery experiment was developed to carry out the research on rubber waveform generator design using uniform experimental design. Through comparing with the firing data the design scheme of waveform generator and impact simulation experiment was made ,which meets the requirements of the technical indicators.The design scheme of waveform was used in a certain type of artillery impact simulation experiment. The rationality of the design scheme and the validity of the simulation experiment was proved by the result of artillery impact simulation experiment.

Abstract: The motor of traditional silicon material possesses the disadvantages of high iron loss, power consumption and a low efficiency. A new type of motor iron core made of amorphous alloy material is put forward in this paper. First, in order to research the stator characteristics of amorphous iron core and silicon steel core, the stator core of three-phase asynchronous motor is fabricated with silicon and amorphous materials. The magnetic performances and alternating loss of the iron cores made by two kinds of materials are tested with in the TD8120 test system. Then, the finite element analysis model of three-phase asynchronous motor is established. The motor of amorphous iron core and silicon steel core are simulated by finite element method. It is showed that the simulation and test results are in good condition within error range. It can be known that the performance and efficiency of motor made by amorphous alloy core are better than the performance and efficiency of motor made by silicon steel core. Results presented in this paper have important significance to carry out the study of amorphous motor.

Abstract: The double derrick as an important part of the drilling rig hoisting system in deep sea oil and gas development, its working environment is much more complex than land rigs working environment. Therefore, in order to ensure the quality of drilling, it is very important to analyze the reliability of the deep double derrick structure and its dynamic load characteristic. Based on the ANSYS software to establish finite element model of double derrick, through the static analyzing to the derrick, get the stress distribution of the derrick structure in static action and the derrick stress deformation trend, provided a reference for evaluation of derrick. Selected the calculation method of double derrick overall reliability index, and according to the results of the finite element calculation of static strength calculated the double derrick overall reliability index, compared with the general standard, know that double derrick with high reliability.

Abstract: Embryonics, a branch of bio-inspired hardware, is a circuit with self-healing capability. Aiming at solving the problems of low efficiency, complexity and etc. during cellular communicating in Embryonics, inspired by the transmission mechanism of hormone, a new type of four-layer Embryonics based on NoC and neighborhood connections is presented in the paper. Operational mechanism and hierarchical four-level self-healing capability of the Embryonics is also analyzed in detail. The proposed Embryonics provides a new approach for self-healing electronic systems design, which may be used in self-healing machine design.