Advanced Materials Research Vol. 544

Abstract: Combining the Maslow’s theory of the five hierarchy demands and the layering consume market diversity, explored the innovation opportunities and the methods from the levels of the different users’ demands, and analyzed the action type in product design, research and development (R&D) process. According to the action type of the layering demands in the process, depending on the product types described the action mechanism of the layering user demands. This mechanism plays the guiding and controlling role in the plan, innovation, design and design management stages of a product development. This research provided an important innovative method for different product design in the R&D process. The research results give a reference for the new product innovation and decisions especially, meanwhile it help us to find the trend of the next generation product.

Abstract: The logistics distribution under the electronic commerce is becoming the vanguard of innovation in circulation filed, representing the main direction of modern marketing. A large number reference about electronic commerce logistics distribution were studied. In this paper, effective countermeasures are proposed for the electronic commerce in Henan Province, through analyzing the impact of various factors in the efficiency of logistics such as information technology and analysis methods of logistics distribution. studies a large number of e-commerce logistics and distribution industry in Henan Province.

Abstract: The multi objective job shop scheduling problem is well known as one of the most complex optimization problems due to its very large search space and many constraint between machines and jobs. In this paper, an evolutionary approach of the memetic algorithm is used to solve the multi objective job shop scheduling problems. Memetic algorithm is a hybrid evolutionary algorithm that combines the global search strategy and local search strategy. The objectives of minimizing makespan and mean flow time are considered while satisfying a number of hard constraints. The computational results demonstrate the proposed MA is significantly superior to the other reported approaches in the literature.

Abstract: For the over-speed failure mode, the method for determining the reliable life parameter of turbine wheel of turbocharger is proposed in this paper. The shortage of design criteria based on conventional safety factor for turbine wheel with over-speed failure mode is analyzed. In order to embody the characteristics of structure and over-speed failure mode, the turbine wheel is taken as a series system consisting of several blade symmetrical components in the reliability modeling process. The time-reliability models of turbine wheel are derived and the relationship between the reliability and failure rate of turbine wheel and life parameter is studied. Then, the method for determining the reliable life parameter of turbine wheel of turbocharger with over-speed failure mode is proposed based on the reliability model and reliability curve. As long as the design parameters including the number of blades, speed, stress, and strength are given, the reliable life of turbine wheel of turbocharger with over-speed failure mode can be determined with the method proposed.

Abstract: The hybrid simulation method based on Multibody Simulation (MBS) and finite element method (FEM) were proposed here and applied to study the relation between carbody structure vibration behaviors and structure fatigue strength characteristic. The detailed steps include: Firstly, rigid-flexible couple vehicle multibody system dynamic model was created and performed to obtain the load time histories corresponded to the typical load cases. Secondly, the carbody structure stresses was calculated through Finite Element (FE) quasi-static stress method. Finally, with the material fatigue property and some uncertainty factors, carbody fatigue damage distribution and life was calculated and evaluated. And the conclusions can be understood that the mechanism between the full vehicle dynamic property and structure damage distribution. The results are also shown that the hybrid simulation technology could be applied into the carbody structure fatigue design.

Abstract: This note investigates the residual lives of the remaining components of an (n-k+1) out of n system with independent and identical components after the kth failure has been observed. Some aging properties and stochastic comparisons on the residual life are obtained.

Abstract: Line heating is the main method for forming compound curved shells of hull. The accuracy of final deformation and the productivity depend on the experience of the workers. To predict the plate deformation, the explicit mathematical model for deformation and the main influencing factors by FEA and GEP is established in this paper. The main influencing factors in line heating process were analyzed firstly. Then, 16 group deformation results of steel plate under the five main influencing factors were obtained by FEA. At last, the explicit mathematical model for deformation and the main influencing factors was established.

Abstract: Collective short fatigue behaviour nearby material micro-structural barrier threshold is experimentally observed for the smooth specimens of Chinese railway LZ50 axle steel. Effective micro-cracks which result in the specimens’ failure were initiated from the material ferrite particles on the surfaces of the specimens. Four elements i.e. crack size, orientation angle, and the two crack tip orientation angles should be contained for each micro-crack. The collective micro-crack behaviour should be described by an equivalent dominant effective short fatigue crack (ESFC) concept using an ESFC theory. And an equivalent method is then developed with an equivalent growth driving energy concept. A random modeling of the equivalent dominant ESFC growth rates is further constructed for describing the random behaviour of the collective ESFCs nearby the material micro-structure barrier threshold. And the kinetic threshold is subsequently conducted from the modeling.

Abstract: Long fatigue crack growth rate (FCGR) model covering the range from threshold to fracture toughness is investigated through a series of experiments on the fatigue crack growth behaviour during nearby the threshold district of stage I, steady growth stage II, and the toughness of railway LZ50 axle steel. It reveals that test data in stage II can be reasonably described by employing a statistical distribution for the FCGR data at a given stress intensity factor range level. While the test data nearby the threshold district can be appropriately characterized using a statistical distribution for the factor range data at a given FCGR level and the case is similarly for the test toughness data. Therefore, the model is constructed using the test data in stage II under a control of the statistical parameters of threshold and toughness data on a principle of concurrent probabilities. Availability is indicated by the modeled result for the present material.

Abstract: Causes are investigated on the earlier failures of the bearings for China railway freight cars with radial bogie. Through observing failure objects, checking manufacturing quality, and calculating rolling contact fatigue (RCF) stresses, it reveals that poor manufacturing quality of bearing outer ring plays a key role to the earlier failures and, in addition, mismatch design of RCF stresses between the outer ring and the inner ring acts as an aid actor. Checks verify that surface and core of the outer ring have lower hardness values than requirements; seldom micro-structures, i.e. black-white bands with thickness of around 0.6 to 1.3 mm, appear in the carburized layer of the bearing outer ring; the white part is needle like martensites with higher hardness values, while the black part is pearlites with lower hardness values; and more contingently, crack like manufacturing flaws may appear in the carburized layer with equiaxed grains of ferrites having lower hardness values are around the flaws. RCF values of the outer ring are much larger than that of the inner ring. But the equivalent RCF stress on the present car with radial bogie is lower than that on other cars. This indicates that main cases of the present earlier failures are due the bearings themselves other than the cars.