Applied Mechanics and Materials Vols. 457-458

Abstract: Microstructure and material mechanical property in the fusion boundary (FB) region of dissimilar weld joints in light water reactors are quite complicated and different from the bulk material, which make it more susceptible to stress corrosion cracking (SCC) and produce high weld residual stress. To investigate SCC behavior in the FB region of an Alloy 182-A533B dissimilar weld joint, considering the mechanical heterogeneity, mechanical parameters ahead of crack tip with different sampling location are analyzed. It suggests that the stress near crack tip would be significantly higher in a high yield stress material while the strain would be much smaller, and the effect of the material properties around FB region on strain is smaller than that on stress. The result of J-integral indicates FB region would be a barrier when crack in Alloy 182 weld propagates towards LAS.

Abstract: This paper presents an overview and example using optimization techniques in casting numerical simulation. Most of the design work can fulfill with the software without human intervention. It really frees the engineer from the amount of trial-and-error that is necessary in traditional modeling.

Abstract: High-quality and high-performance gear research is a significant key technology research projects in energy, transportation, chemical industry, metallurgy common areas. The vibration and noise of gear transmission mostly come from the working gear transmission. The dynamic properties of gear transmission include the dynamic load of gear transmission system, the mechanism of vibration and noise, computing and control, which are the main directions of the future research.

Abstract: Tardiness scheduling problems in the lean production has received extensive attention recently, and in most tardiness scheduling problems job due dates are regarded as invariable and known in advance. The study deals with fuzzy tardiness scheduling for parallel machines with fuzzy job due dates, where the objective is to minimize the average penalty cost of jobs tardiness. To describe the tardy degree of job clearly, a novel tardiness measure index is introduced based on the possibility and necessity measures in the study. And further, the mixed integer programming scheduling model of parallel machines is constructed for jobs tardiness. Since this problem is NP-hard, an improved simulated annealing is proposed and designed to solve the model. Finally, a numerical experiment is presented to illustrate the feasibility and effectiveness of the proposed method.

Abstract: Printed Circuit Board Assembly (PCBA), is an important basic part of Electric and Electronic Equipment, which has lots of high-value components and toxic substances. Normally, when Electric and Electronic Equipment (EEE) is scraped, some components on waste PCBA still keep good performances. Therefore, it is feasible and economical to environment-friendly reuse the high-value components on waste PCBA. In order to guarantee the quality of the disassembled components, the components reuse-oriented disassembly process is proposed, in which the mechanical and physical characteristics of solder and the joint type of PCBA are considered comprehensively. In the process, through the analysis and measurement of the temperature distribution of PCBA, the optimized heating mode and heating temperature curve can be drawn up for the different joint type of PCBA. For getting the disassembly mode of PCBA, the disassembly force and separating displacement of components on PCBA are defined and the disassembly energy models for different kinds of components are set up. On the basis of the heating mode, heating temperature curve and disassembly energy, two kinds of disassembly apparatus and a performance testing procedure for certain kinds of old components are developed. In the end the components reuse-oriented disassembly process parameters are optimized to get a high separation ratio and reuse ration of components with orthogonal test.

Abstract: Through the study of regular polygon cross section continuous forming processing technology of rotary cutting machine, this article designed a profiled bar turning peeling machine. This machine is mainly composed of workpiece axis, cutter axis, feed device and pulling device, etc . Parallel mounted, workpiece axis and cutter axis rotate at a rotational speed ratio in the same direction so as to form complex turning motions, during which the cutting track of the knifepoint relative to workpiece axis forms a shape of approximate linear closed curve, at the same time, feed device and pulling device pull workpiece moving along the axis, through which this machine can complete a turning finish of a whole workpiece at a time. This article analyzed the turning peeling principle of profiled bar, established a motion trajectory equation for the knifepoint relative to the workpiece axis, analyzed the processing straightness error of turned profiled bar, and then derived the error calculation formula.

Abstract: Concrete pump truck plays an important role in national economic development and infrastructure construction. The boom system is one of the most critical parts of concrete pump truck, so it is important to analysis the strength. In this paper, the research is on the concrete pump truck of 37 meters. The three-dimensional model is established in PRO/E. Then the model is imported to MSC.PATRAN / NASTRAN and the strength is analyzed. The results show that the maximum stress on the boom is far less than the yield limit of the material, the structure meet the strength requirements.

Abstract: For CNC machine tool, reliability is the key to its quality. Load spectrum is a time-domain distribution of load, and is the key to reliability design and test of CNC machine tools. In order to obtain the load spectrum for reliability test, this paper researches the load spectrum of the typical CNC lathe and CNC milling machine through the analysis and calculation of the actual machining information, and presents the analysis and calculation method of load spectrum, and gives the CNC lathe and CNC milling machine load spectrum curves through actual data examples.

Abstract: The principle and design of the durable performance experiment test-bed for the pilot operated directional valve is introduced in this paper.

Abstract: Coolant for gundrill under MQL is impermissible to be high pressure, large quantity, or direct emission on the interface. These restricts would be seriously unfavorable to lubrication. Experiments reveal that poor lubricating always appear on the hole periphery with dark burns on the hole wall. A prospective solution is to regulate the pressure distribution by modifying the dub-off structure. Its derivation is detailed in this paper. Its validity is demonstrated by practical experiments.