Applied Mechanics and Materials Vols. 148-149

Abstract: Thin film lubrication (TFL) and elasto-hydrodynamic lubrication (EHL) are different lubrication states, their lubrication mechanisms are different, but the transition from EHL to TFL is a continuous process at the aspect of film thickness change, it is important to establish a physical-numerical model that can be suited for both EHL and TFL. Based on rheological, the change of micro thickness is expressed by the change of viscosity, then the micro problem of TFL can be turn to macro problem. The adsorption layer is divided into two parts formatted by static contact and shear force in the calculation. In a given static adsorption film, other oil film parts will be comprehensive consideration, modified formula of the overall average equivalent viscosity is gained by the method of combining numerical calculation and experiment, then numerical model is established for both EHL and TFL. TFL and EHL typical characteristics and the effectiveness of the model can be obviously shown by the results.

Abstract: Cast aluminium alloys often contain microstructural defects resulting from the casting process such as porosity. Developments of Lost foam casting (LFC) process is considered as one of the most rapid in casting technology owing to its unique advantages on energy savings and capabilities to produce castings with thin sections. In the present research, experimental investigations in lost foam casting of aluminium-silicon cast alloy, LM6, were conducted. The main objective of the study was to evaluate the effect of different pouring temperatures, slurry viscosities, vibration times and sand sizes on the porosity of castings. A stepped pattern was used in the study and the focus of the investigations was at the thinnest 3 mm section. A full 2-level factorial design experimental technique was employed to plan the experiment and subsequently identify the significant factors which affect the casting porosity. The result shows that increasing in the pouring temperature decreases the porosity in the thin-wall section and finer sand size is more favourable than coarse size for LFC mould making process.

Abstract: Adopting a three-dimensional contact finite element method, with complex connecting rod group assembled body model of computation, the fatigue strength of the connecting rod of a certain type of diesel engine was verified. A transient stress analysis was conducted on the connecting rod. Compared with the connecting rod static stretching and compression test, the three-dimensional contact finite element method, which was used to analyze the strength of the connecting rod subassembly, was feasible. Based on the three-dimensional contact finite element method, the connecting rod transient stress analysis results showed that the maximum stress of the connecting rod did not occur under the highest pressure of the cylinder, and the dynamic stress value was less than the static stress value.

Abstract: Basic performance test was performed on a newly-developed compound antifreeze and experiment was carried out to study the basic performance, mechanical property and durability of the concrete mixtures containing 0%, 4% and 5% antifreeze. The result shows the antifreeze may be used for the concrete construction at 20°C below zero and it has favorable performance for winter construction. When the amount to be added is 4% and 5%, the ratio of compressive strength of 28 days shall be 105% and 107% respectively; the ratio of compressive strength of 56 days shall be 114% and 112% respectively. In freeze-thaw cycle experiment, 50 times of freeze-thaw strength loss rate is 45.3% and 44.8% of the strength loss rate of the concrete without the antifreeze. The water-reducing ratio of the antifreeze, ratio of bleeding rate, air content, difference in setting time, strength ratio, ratio of shrinkage, permeated height ratio and other performance indexes all satisfy specification requirements.

Abstract: For those underwater vehiclees always stored in underwater vehicles-boxes which are filled in nitrogen annoys,the paper provides a formula of calculating storage reliability and relevant cases.Based on this,according to actual launching frequency of trial mission and storage time.It sets up the formulas of each underwater vehicle on launching frequency、maintenance frequency and the frequency of shore-based ohmic exercises.The results of calculation indicate that they are of high practicability and applicability,and can be applied in theoretical analysis on current storage reliability of underwater vehiclees in commission.

Abstract: Multi-plate wet friction clutch is one of key components of duty truck hydrodynamic-mechanical transmission. Super-heated burn and warping deformation are main invalidation forms of wet friction clutch. It is one of effectual methods to augment friction coefficient and prolong natural life of wet friction clutch that friction disks’ surface temperature and radial temperature are reduced. Compute method of friction disk surface temperature is obtained using theory analysis and confirmed correctness using finite element analysis. It is salience character of wet friction clutch that there are some oil grooves in friction disk surface. These oil grooves can increase friction coefficient and emanate heat quantity. Confirming conformable friction disk’s surface oil groove configuration by experiment research is received. It confirmed that the appropriate surface oil groove configuration of friction disk should be double-arc groove.

Abstract: Singlet oxygen generator is the heart of chemical oxygen iodine lasers and has been the focus of research for many years. In this paper, a novel singlet oxygen generator with rapid separation technology is briefly put forward. To ensure short residence time, the design of reaction and separation processes happening simultaneously in through-flow reactors is dumpy shaped. By means of computational fluid dynamics, the calculations indicate that the residence time of O2(1Δ) in the new structure is about 15ms and the new SOG has excellent anti-entrainment and defoaming separation performance. The analytical results show the new structure is a feasible and promising technology in singlet oxygen generation cases.

Abstract: The combined heat and power plant furnish heat and electric, which are two different quality energy. And benefit returns to electric, benefit returns to heat and their trade off compose three methods to share the cost of the combined heat and power plant. Theory of energy grade is the thermodynamic viewpoint, which is not only considering the energy conservation, but also the energy matching. It takes into account all the quality and quantity of the utilized energy. In the present article, theory of energy grade is applied to analyze the heat usage of heat consumer. That takes the price of electric as basis. This method simplifies the calculation, has the reasonable theory foundation and meets the practice condition. It also reflects the idea of using energy according to the quality and high quality, high price

Abstract: As one of the key technologies of Hybrid Electronic Bus, regenerative braking technology can recover energy without changing the traditional bus braking habit. This is of vital importance in the research of regenerative braking system. Because the braking force distribution relationship between the front and rear axle of the vehicle has a remarkable influence in the braking stability,especially adding the regenerative braking force, the influence is even larger. So the anti-lock braking control strategy for the hybrid electronic vehicle is updated in this paper according to the condition of regenerative braking. The anti-lock braking control and regenerative braking control were integrated in one ECU (Electronic Control Unit) of braking control system, collecting signals of wheel rotate speed, vehicle speed, SOC and brake pedal position by CAN bus. And the output control commands are sent to the execution unit of anti-lock braking system and regenerative braking system. The effectiveness of energy regeneration and the braking stability of this strategy are tested on the off-line simulation platform.

Abstract: A new type of aluminum lithium alloy Al-Li-S-4 was investigated in this paper. Process of phosphoric acid anodization and method of making bonding joint sample was introduced. Micrographs of plate surface were study by scanning electron microscopy. The pattern of aluminum alloy was modified after anodization. Plates were bonded with FM94 film adhesive and cured at 121°Cin the special clamping fixture. Morphology of bonding sample cross-section interface was investigated after bonding and curing process.