Applied Mechanics and Materials Vol. 415

Abstract: The paper deals with the stabilization of low damped astatic systems. They show a low value of a relative damping and consequently a high resonance rise of amplitude frequency response. If astatism occurs in an automatic control system, the situation becomes complicated due to the exhaustion of a phase safety of astatic element. In order to achieve the stabilization, a filter with rejections has been designed. The filter is characterized by rapid rejections of logarithmic frequency characteristics that eliminate resonance rise of a low damped astatic system. A functional model of a discrete filter was created to attest the properties of the filter with a continuous low damped astatic system. Experiments have proved the suitability of the filter application. The method of the filter utilization, the stability of the low damped astatic system as well as the stability assessment by the operator W will be described in the paper.

Abstract: To improve dynamic properties of frame structure uses the method of sensitivity analysis of optimizing the thicknesses. And adopting the way of combining the partial sensitivity analysis with global sensitivity analysis finds out important design parameters, which can ensure the ideal dynamic performance of the frame structure and make the frame light in weight.

Abstract: Aiming at the limitation problem of constant dynamic parameters for classical vibration absorber, a new cantilever beam-type absorber device is designed which is composed of a continuous beam and mass block, a vibration isolation system model with a beam-type absorber is established, the absorption frequency of the mass block at different positions is calculated. And based on the software of ADAMS, the frequency response characteristics of the system are obtained. Finally, the good vibration absorption of the beam absorber is verified. The results show that the feasibility and effectiveness of cantilever beam-type absorber is confirmed, and the dynamic vibration absorber with continuous adjustable parameters is achieved.

Abstract: In this paper, the seal principle of high pressure gas is deeply analyzed. In addition, the thermal compatibility between a piston and a cylinder of the accumulator are simulated by finite element analysis. Furthermore, a new project of high pressure oil sealing high pressure gas is developed. The study and experimentation show that this project greatly improve the seal performance.

Abstract: Conventional arc surfaced cam curve fitting mostly used the least squares to realize, however, arc surfaced cam required to ensure the movement curve of the displacement, velocity and acceleration continuous smooth. Therefore, it needed multiple order correlation analysis of arc surfaced cam motion data, to get the correlation coefficient and its similar morphology category of arc surfaced cam actual movement in surface of position, velocity and acceleration, to provide a theoretical basis for further improving surface machining precision of arc surfaced cam motion.

Abstract: The vibrating modes of vibration screen box can be divided into single degree of freedom excitation and multiple degrees of freedom excitation. This paper puts forward the conception of multiple degrees of freedom excitation and sets up the dynamic equation of multiple degrees of freedom excitation vibration screen while the characteristics of one freedom vibration screen are summarized. Through the MATLAB programming language, using the four order Runge-Kutta method, we do a dynamics simulation research on an instance for this type of vibration screen, and analyze the characteristics of this type of vibration screen.

Abstract: Delicious food always attracts people. To choose a suitable baking pan to bake food in the oven is worth to be discussed. With reference to the relevant theory of communication networks, this paper established a regular polygon without node coverage model, and discussed the relationship between the placing mode of the pans and the utility rate of space in the oven. It concluded that the honeycomb coverage of regular hexagons in the oven has the best baking effect.

Abstract: For the heat distribution problem of the baking dish food in microwave oven, we established a partial differential equation model for the unsteady heat conduction problems, and solved this model by using the finite element method. Then, we drew the figures of temperature field distribution for the circular pan and the rectangular pan at a certain time respectively. Based on the conjecture that the part of their internal circular area for the graphics between the circle and rectangle are uniformly distributed, we verified the relationship between the pan evenly heated area and the shape of the pan, then we got the maximum heat distribution area for the circular pan and the rectangular pan, rectangular pan and regular hexagon pan.

Abstract: A multi-chip white-light modeling algorithm for high color rendering index and high color uniformity of surface mounted LED devices is demonstrated. The simulation of white-light LED model, according to the principle of additive color mixture by four color of red, amber, green, blue LEDs and using the commercial software program to perform Monte Carlo ray tracing has been developed. The simulation and experimental results show that the performance can be achieved with a number of LED chips.

Abstract: Because a uniform fragments field is needed for forward-firing warhead intercepting air targets, it is necessary to analyze quantitatively and improve fragments dispersion uniformity. The wave controller is added in the warhead to make fragments at marginal zone close to the dispersion center. The static explosion experiments are performed to obtain the fragments dispersion data before and after the warhead being improved. The results of data analysis indicate that the marginal fragments will close to the center after adding a suitable wave controller in the warhead. And at the same time the field density of fragments in the centre zone changes little. The fragments radial dispersion uniformity is much better than before. The effective fragments area is about 1.8 times larger than before, and the fragments quantity in effective fragments area increases 54.2%. But about 30% of total fragments are still not used effectively because of the sparse density, and the problem needs to be researched farther in the future.