Applied Mechanics and Materials Vols. 278-280

Abstract: Aim to fulfill the design requirements of a pneumatic proportional directional valve, a novel bidirectional proportional electromagnet with integrated lineal Hall position sensor was proposed. Magnetic circuit model and finite element model were established separately. Both static force vs. armature stroke characteristic and Hall sensor output vs. armature position were tested on a newly designed test platform. The experimental result shows a good linear magnetic spring characteristic of the proportional electromagnet, which further ensures a unique spool auto reset capability for directional valves. The mass of the armature is considerably reduced, thus it will benefit the overall performance of high speed pneumatic proportional directional valves.

Abstract: The Compressed-air (CA) engine car is receiving increasingly worldwide attention because it takes advantages of renewable energy and has zero exhaust emissions. However it is limited by its low efficiency. This paper focuses on a systematic study on valve timing for optimizing its efficiency and performance. The requirements for the valve train were presented and an optimized polynomial cam profile was applied. Using the programme of Matlab, the influences of the half wrap angle and the maximum valve lift to the fullness coefficient were studied. The article proves that the designed cam profile should use the minimum maximum valve lift to receive the maximum fullness coefficient.

Abstract: In AC industry chilled water storage (CWS) systems are one form of cool thermal storage technology that can be used to time shift the electrical load of the system from the peak day periods to off peak night time periods. In this paper the data for the actual exported and generated electrical energy obtained for the power stations has been used to estimate the electrical energy consumption and the peak electrical load of AC systems. Since the chiller in an air cooled AC system represent more than 75% of the total electrical power consumed by an AC system during the peak demand period, the impact of using CWS systems with alternative operating strategies including partial(load leveling ),partial (demand limiting) and full load has been investigated. In our conclusions we estimate that approximately 45% of the total annual exported electrical energy is consumed solely by AC systems as a result of the very high ambient temperatures. Furthermore, it is estimated AC systems represent about 62% of the peak electrical load. The results demonstrate that CWS can reduce the peak electrical load of a chiller in an air cooled AC system by up to 100% and reduce the nominal chiller size by up to 33% depending up on the operating strategy adopted. This is achieved with only a 4% increase in power consumption of the chiller for all CWS strategies except for full storage where the energy consumption actually decreases by approximately 4%.

Abstract: Three-dimensional digital model of hot rolling-mill housing was built. The natural frequency and vibration mode shape of the first 10 order modes of hot rolling mill housing were calculated using ANSYS software. The vibration mode shape was studied in detail. The striking vibration signal and subsequently the natural frequencies were measured by placing two 3-Dimensional accelerators in the key points of the rolling mill horsing. Theoretical calculations and experimental results verified each other，high agreement was shown between the experimental results and the theoretical results. The first 10 mode frequency all appeared in the experiment signal with low error. The main mode frequency (117.3Hz) of the experimental signal has the lowest error down to 0.07%.

Abstract: A CA3GA2 lean combustion gasoline engine one dimensional model was built by AVL BOOST software. The relationship between air-to-fuel ratio (A/F) and emission characteristic and fuel economy was simulated. Simulation shows that: (1) CO emission decreases as the A/F ratio increases; (2) HC emission reaches its lowest point at A/F=16~18; (3) NOX emission reaches its highest point at A/F=16~18; (4) the engine lean combustion limit is A/F=22, the brake specific fuel consumption (BSFC) decreases as the A/F ratio increases within the lean combustion limit.

Abstract: This paper introduces the development of a tool for modeling and analysis of BTF toolholder-spindle system, based on ANSYS software. The tool is developed in parametric design method. Most parameters are defined automatically except a few parameters requiring users to input, which improves the modeling efficiency greatly. The interface joint of the BTF toolholder-spindle is established by adopting spring-damping model and defined by custom element unit Matrix27. The proposed model reflects the characters of the joint on the properties of BTF toolholder-spindle effectively. A case study is given to verify the efficiency and accuracy of the developed tool.

Abstract: In this paper, to solve the problems of tappet damaged seriously and mechanisms abnormal sound that existed in a high-speed gasoline engine, the valve train simulation software AVL-TYCON was applied to perform both kinematic and dynamic analysis. The results show that the original speed and acceleration curves of intake valve train are not smooth enough and the contact stress is excessive high. The intake cam was then redesign to improve the overall performance of the engine, and results are verified through experiments

Abstract: To improve the efficiency of the auxiliary transportation system in the coal mine, the monorail auxiliary transportation system was built with the analysis of monorail’s adaptability and road section, and calculation about locomotive selection. The key link of the system’s popularization and application were proposed. The system provides practical significance to improve environment, enhance efficiency and ensure safety in transportation.

Abstract: At present, a dozen of the wheel running machines being used in Japan. Through fatigue tests with wheel running machines developed, the failure mechanism and the fatigue strengths of reinforced concrete slabs were clarified. Our country needs the new technologies based on the theory from the wheel running machines. Those technologies should be carried out continuously and spread of the technologies to the world is strongly expected.

Abstract: In order to clear up the burrs on soft magnetic ferrite without damaging the work-pieces, complex Gauss ultrasonic horns was designed. The complex Gauss horn was consisted of two cylinder sections with a Gauss section in the middle. Its profile and parameters were calculated by the theories. The design was verified by comparing the results of theoretical calculating with the result of finite element analyzing. The shape factor of complex Gauss horn is 47% higher than stepped horn with Cone transition section