Applied Mechanics and Materials Vols. 385-386

Abstract: Aimed at investigating efficient cutting method with a lower energy consumption, higher reliability and life, and researching the intrinsic relationships between ability of picks' breaking coal rock and related factors, this paper simulates the dynamic process of conical pick cutting coal rock by using ABAQUS/explicit, analyzes cutting load statistics, and evaluates the similarity of simulation results and test results quantitatively using Pearson correlation coefficient. The results indicate that the simulation results are in good agreement with the test and the theoretical results (the error is within 10%), the description of the variation law and influence degree of the cutting force, propelling and lateral force along with the pick cone angle and installation angle, the average gradient of three force variation, the ratio range of propelling force to cutting force (0.18~0.34) and variation tendency along with the installation angle and the cone angle. Positive or negative alternating direction of lateral force proves that cutting slots on both sides of coal rock existing non-simultaneous avalanche phenomenon in cutting process. The study provides the reference for the simulation of pick cutting and cutting mechanism broking coal and rock under considering the anisotropy of coal rock and beddings and joints.

Abstract: Coke pusher ram of coke pusher machine on 6 meters coke oven sometimes vibrates severely, even have strong resonance which can make the hole pusher machine vibrate. This vibration produce great harm on pusher ram and pusher machine and relevant equipment. This phenomenon is common, you can find it on many domestic pusher ram of pusher machine on coke oven. In order to improve the stability of pusher ram on the work, it is necessary to find some reasons which may lead to coke pusher ram’s vibratory.

Abstract: This article, combining the robot theory, applies the serial parallel manipulator to the configuration to design a flexible assembly tooling, which is used for aero-engines of different types and models. First, the inverse kinematics solution and workspace are analyzed, then a model in Adams is built to simulate the kinematic characteristics. Finally, the simulation result is used to contrast with the theoretical calculation to verify the correctness, and to solve forward kinematics. This work has outstanding theoretical and practical significance for assembly accuracy improvement, optimizing assembly performance and dimensional synthesis.

Abstract: Based on the geometric and kinematic relationship between the spiral guide rollers rib and the grinding wheel in the rib grinding with the special machine, the ribs shape surface after grinding was analysised, and the equations for the ground rib axial profile were established. Numerical analysis was conducted in an example, and the results show that the ground rib axial profile is approximately linear in most region, but seriously nonlinear in the root region of about 0.5mm height, and the profile inclination direction changes when the vertical angle of grinding wheel head is less than a value which is slightly less than the helix angle of the guide roller.

Abstract: To predict the working performance of the jet refrigeration system more precisely, including the condensing temperature and coefficients of performance, this paper presents a 1-D analysis model with the varying specific heat ratio. During the evaluation, the working process of the constant pressure ejector is divided into three sections with different specific heat ratios. By comparing the results from Eames experiment, the simulation results indicate that this model is more reasonable, and the error of the simulation is within 20%, which is significantly smaller than the error of Eames model at 40%.

Abstract: Based on the catenary equation, we deduced the gravity and rotation inertia formula of catenary, and obtained the tangent angle of each point on the rope , the tension of the rope and other mechanical parameters. Then we discussed two kinds of situation and calculated all of the corresponding parameters with the Mathematica, and analysis the trend of these mechanics parameters in detail and the numerical results demonstrated the properties obtained. The methods we employed in calculation and analysis can be applied in analyzing the properties of tension and stress of dangling cables in engineering.

Abstract: Connecting rod mechanism under the condition of high speed operation, organization, the elastic dynamic response of not only makes institutions of trajectory deviation, at the same time also can cause fatigue failure, the article from the perspective of more accurate nonlinear dynamic model is established, the analysis of linkage performance and characteristics of mechanical vibration, look for the causes of various kinds of vibration, and puts forward corresponding preventive measures and control strategy.

Abstract: In order to improve refrigeration system stability and efficiency of the low pressure difference between thermostatic expansion valve, it is researched that the refrigeration system is the refrigerate capacity of the HSN7471-75 compressors. The system performance is analyzed and compared in the case of with and without refrigerant pumps. The results indicate that the COP of the refrigeration system with a pump can increase 31%. The reliability of system is also improved.

Abstract: By process analyzing of the mobile phone cover, the overall mold structure and key design points for this product was introduced, the typical design methods for this kind of mold such as angle lift core-pulling mechanism and angle pin core-pulling mechanism were discussed. The part was ejected easily by adopting the angle lift mechanism and double ejection system. The working process of the injection mould was analyzed. Industrial practice proved that the action of the core-pulling mechanisms, ejector mechanisms and resetting mechanisms was stable and reliable.

Abstract: An 8-dof vehicle vibration model with four-wheeled random road inputs was established. The frequency-domain method was applied to researching the random response of linear vehicle dynamic system. The results show that the frequency error calculated by the 8-dof model is small, but the amplitude is slightly large. Hence, it has referential value to use a simple model to estimate the peak frequency of a practical system. The model of vehicle dynamics as well as the method and program of the calculation of its vibration can predict the ride comfort and safety of the vehicle, and can also provide the scientific basis of researching the stability of vehicle and its influential factors.