Advanced Materials Research Vol. 650

Abstract: This report is mainly performed to investigate finite element (FE) modeling and post-processing capacities for fracture mechanics analyses characterized by the stress intensity factor (SIF) at successively stationary crack tip positions. As part of a linear elastic fracture mechanics (LEFM) analysis, the determination of stress intensity factor distribution can also be adopted by J-integral approach. The aim of this report is to review three papers related to estimate J-integrals through FE study and represent the theoretical backgrounds. Furthermore, the technical details for both FE modeling and SIF evaluation will be described in this report based on complete understanding of three reference papers. These numerical approaches to deal with SIF evaluation of general cracks can be applied in 2D and 3D FE models.

Abstract: The Hybrid (hydrodynamic/ hydrostatic) journal bearing system has found wide spread application in high speed rotating machines such as compressors, gas turbines, steam turbines, etc. The present studies include solution of Reynolds equation for hydrodynamic journal bearing with infinitely long approximation (ILA), infinitely short bearing approximation (ISA) and finite journal bearing approximation. Further Finite Journal bearing approximation considers two dimensional solution of Reynolds equation with natural boundary condition, which cannot be solved by analytical method. So, here the solutions for finite journal bearing have been done with finite difference method (a MATLAB^® code is prepared for finite difference method) to get bearing performance parameters such as load capacity, Sommerfeld no., etc.

Abstract: ×Χ×We demonstrate here an optical triode from the principle of electrically induced quadratic cascading in single lithium niobate optical superlattice, predicted by the united theory of second-harmonic generation/parametric down conversion and electro-optic effect. In the optical superlattice, the e-polarized fundamental wave is first converted to double frequency one with the same polarization. At the “on” state, the PDC after SHG is triggered by a weak o-polarized fundamental wave (control wave) with the aid of applied electric field at the point where fundamental wave almost exhausted; finally, the double frequency wave is converted again to e-polarized fundamental one as high output. And when the control wave is absent, only the SHG takes place; fundamental output is at “off” state. The optical triode would have a response shorter than ps and a amplification ratio of 2*10³

Abstract: The automation level has a great influence on the consistency of batteries. By now, an improvement of formation process has proposed new requirements for the formation equipment. This paper brings forward the application of double plus chain mechanism to formation equipment. The chain running at a low speed, the batteries on it move quickly and smoothly. The stopper can stop them for some specific operations without blocking other battery packs. PLC cooperating with signal input and receiving units makes it easy to meet the control requirements. If process changes, we only need to adjust the location of detection devices and execution units. Thus, the control system is very flexible and adaptive.

Abstract: In recent years, the environmental and rechargeable Li-ion battery has become a hot spot in new energy technology field. The performance of Li-ion battery is in a large part affected by the advanced special equipment. The current and voltage needle is an important part in the special equipment. Based on the existing current and voltage needle, the paper designs a new current and voltage needle which is used for Li-ion battery formation. In this paper, we make a detailed analysis of mechanical structure and point out the superiority compared with the existing current and voltage needle. Cooperating with other formation equipment, it has achieved good economic benefits for the enterprise.

Abstract: Object Stress rates to predict the behavior of material have been researched based on numerically and theoretically for researchers who study continuum mechanics due to its complexity. This study focused on the various objective stress rates which assumed the finite deformation theory. Eight object stress rates (Oldroyd, Truesdell, Cotter–Rivlin, Jaumann, Green–Naghdi, Eulerian, grangian, and logarithmic object stress rates) were introduced using continuum mechanics and analyzed to derive the numerical solution to the simple shear problem. Numerical results from each object stress rate were analyzed and compared with the results of the other stress rates. Finally, the appropriate object stress rate for the simple shear problem was determined based on the numerical results from eight objects stress rates.

Abstract: To solve the problem of low lift to drag ratio of Magnus cylinder airfoil, the Computational Fluid Dynamics software Fluent was used to study the principle of a drop of the drag force of cylinder when rotating. And the principle was used to further reduce the drag of rotating cylinder. A traditional airfoil head and a triangle tail was used to study the effect of the aerodynamic performance change of the combined airfoil. A conclusion was made that with a suitable profile of the tail would reduce the drag force of the combined airfoil thus increase the lift to drag ratio of the airfoil. At last an orthogonal test was made to determine the size of the tail airfoil. The result show that the optimized airfoil reduce the drag force to 50% of the original cylinder and improve the lift to drag ratio to 50%.

Abstract: Based on the rigid-flexible coupling virtual prototyping technology, the entities model of wheel loaders structural system was established by using Pro/E, then it was imported into the ADAMS environment and constraints were added to create a rigid model, and the corresponding rigid body was replaced by the model neutral file generated by ANSYS, thereby the rigid-flexible coupling virtual prototype was established. The speed and acceleration curve of bucket in a work cycle, the dynamic stress of link and the rear frame was achieved, and the dynamic characteristics of the bucket was analyzed. This paper can provide a reference for similar models of rigid-flexible coupling dynamics simulation.

Abstract: The shortage of energy prompts Li-ion battery to become the new alternative energy. In order to master battery characteristics, solve the battery safety problems and prolong service life, it is necessary to research essentially the battery performance, cycle life and capacity, which can provide the basis for the development of battery management system. In this paper, we build a set of Li-ion power battery testing system of charging and discharging according to the existing equipment, test the battery pack through a combination of the hardware and software, and put forward a set of complete testing method. Then on the basis of the test data and the relation curve between Li-ion power battery capacity and cycle times, we have proved that the testing system and testing method are effective.

Abstract: This study developed a set of equipment that can measure the treadmill exercise energy consumption accurately, and apply the exercise energy consumption to refrigeration and heating devices, thus supplying hot water and chilled water for users. Exercise energy consumption is conventionally measured based on the amount of exercise, but this study used non-electric mode to drive refrigeration and heating devices. According to the measurement results, the heat energy generated by exercise energy is 65 kcal; as compared with the 70 kcal measured by calorie meter, the result is within 10% of error range, thus proving that the proposed measuring method is worth research and development. In addition, without conventional energy sources, 3,000c.c of hot water (45°C) and 1,500c.c of cold water (7°C) could be generated within 20min use of the treadmill. The proposed equipment can measure the exercise energy consumption, and support the refrigeration and heating system to produce free hot water and cold water. This is an environmentally-friendly and innovative multifunctional equipment worthy of further research and development .