Applied Mechanics and Materials Vol. 159

Abstract: An improvement ant colony optimization(ACO) is proposed to solve the simple assembly line balancing problem of type-1 (SALBP-1) which aims to minimize the number of workstations for a given cycle time of assembly line. In the algorithm, three heuristic factors and two pheromones: (1) the pheromone between task and station, (2) the pheromone among tasks, are introduced to design the selection mechanism which is used to select task for station. The task assignment mechanism is proposed to assign suitable tasks to station. Ants select task based on selection mechanism, and then assign suitable one to station according to assignment mechanism. The result of literature test problems indicates the effectiveness of the proposed algorithm.

Abstract: Titanium is present in the earth’s crust at a level about 0.6% and is therefore the fourth most abundant structural metal after aluminum, iron, and magnesium. High strength, low density, and excellent corrosion resistance are the main properties that make titanium attractive for a variety of applications. The major application of the material is in the aerospace industry, both in airframes,engine components,steam turbine blades, superconductors, missiles etc. or corrosion resistance, for example marine services, chemical, petrochemical, electronics industry, biomedical instruments etc.In this study, wire electrical discharge machining (WEDM) is adopted in machining of commercially pure titanium (Grade-2). During experiments, parameters such as Pulse on time, Pulse off time, Peak current, Spark Gap set Voltage, Wire Feed and Wire Tension were changed to explore their effect on the cutting rate, gap current and surface roughness of the machined specimens. The ranges of process parameters for the experiments were decided on the basis of literature survey and the pilot experiments conducted using one factor at a time approach(OFTA). It is found that the intensity of the process energy does affect the cutting rate, gap current and surface roughness as well as, the wire speed, wire tension and dielectric fluid pressure not seeming to have much of an influence.

Abstract: This research is aimed to achieve TPU-based TPU/PA6 blends which is equipped with both considerable mechanical properties and antistatic performance by blending with different portions of compatibilizer EVA-g-MAH and conductive carbon black with twin screw extruder. Results indicate that, the EVA-g-MAH not only improves the blend’s compatibility but also the mechanical properties. DSC results show that the gap between the glass transition temperatures of TPU and PA6 got shorten after adding EVA-g-MAH. The 70TPU/30PA6/15 EVA-g-MAH has better mechanical properties which are congruent with the findings of the SEM, and when this ratio was blended with different portions of conductive carbon black, their mechanical properties almost retain the same, but the blends obtain the antistatic property eventually. While lowering the production costs, the industrial application scope of TPU is widened especially the fields which have high requirement for antistatic property, such as electronic, medical, automotive, packaging, etc.

Abstract: Drive as the high-speed elevator's power input device, its function is to drag car and counterweight running in the hatchway. Drive's working status has significant impact to elevator's safety, dependability and comfort. Through the FEA on high-speed elevator's drive machine, and basis theoretical is used to provide reason for stress calculating and theoretical analyses. First, treat the drive device's stress with reasonable structure simplifying. Second, by the Plug-in SolidWorks COSMOS exert 3D modeling on load and constrain. The last, executing the FEA gets stress and strain cloud. Contrast the FEA analysis on the drive device with actual observation outcome, it shows that they are similarity, the analysis outcomes demonstrate the method of research to be reasonable, it has great meaning for high-speed and great capacity elevator's research. Provide directions for in-depth development.

Abstract: Those ultimate reasons of over-cladding and under-cladding are indicated through analyzing between the existing parallel scan mode and the characteristic of metal laser deposition shaping. A kind of scan path generating method is presented, firstly, scan path is generated base on grouping internal parallel filling scan according to the set scan space in the same layer, then, scan direction is changed base on matching different scan space in different layer. Practical application shows that the scan path can effectively enhance the flatness of shaping layer and the fabrication quality, ensure to shape successfully.

Abstract: CuO microspheres are successfully synthesized with CuCl2 as copper source and Na2CO3 as auxiliary salt at 240 °C for 24 h via the easy hydrothermal method. The phase and the morphologies of the samples have been characterized and analyzed by XRD (X-ray diffraction) and SEM (Scanning electron microscope), respectively. XRD analysis shows that the phase of as obtained samples is CuO. SEM analysis confirms that the increase of the reaction time, the reaction temperature and the auxiliary salt is propitious to synthesize CuO microspheres.

Abstract: A customer involved digital NPD method is addressed. This study extends new product development (NPD) to a new field; Customer Involved Digital New Product Development Method addressed in this paper is based on integrated application of customer interaction, customer needs elicitation, CAD, CAM, CAE technology. It makes RD process more quickly and more effectively compared with the traditional NPD method. This study finds that the more effort on pre-NDP process, the less likely it might encounter risk of failure. Thus, a better NPD performance can be achieved by customer involved digital NPD method (CIDNPD). A case study of scooter NDP is used to illustrate the new method. We believe that the proposed methodology will have a positive impact on the future new product development.

Abstract: Three forms of animals’ adhesion were analyzed: hairy adhesive pads, smooth adhesive pads and claw. Scanning electron microscope (SEM) was used to observe the surface of friction plate with different particle diameters. It’s found that the particle could be seen as conical shape. The self-designed lever-like testing equipment was also used to measure the adhesive force of drosophila melanogaster contacting 6 substrates with different roughness. It was shown that adhesive force decreased first and finally rose with the increase of surface roughness. When the roughness (R value) was about 68.5nm, it showed that the lowest adhesive force was 0.0085mN. Then model of the Van der Waals force was established. In this model, contact form between seta and the substrate was divided into five states, and the theoretical adhesive force at each state was calculated, which successfully simulated with the actual value. However, when surface roughness reached the situation that the gap between adjacent particles was greater than 2μm, the gripping function of the claw made the actual value greater than theoretical one. It was concluded that adhesive force was a compound function of the Van der Waals force generated by hairy adhesive force and the gripping force generated by claw. So it was also speculated that the fibrous fine pads of insects were the basic form adhesion on smooth surface of the substrate.

Abstract: Titanium alloy (TC18) is new style alloy (α+β). It possesses better performances than common titanium alloy. However, Titanium alloy (TC18) is still classified as difficult-to-machine materials for their poor machinability, which is attributed to relatively low modulus of elasticity, strong alloying tendency or chemical reactivity with cutting materials at higher temperatures and low conductivity of heat generated by the cutting action. Due to the poor machinability of the alloys, selecting of insert style is crucial for tool life and material removal rate. In this work, milling tests, using three kinds of inserts (KC522M, YD201 and SANDVIK 4240), were carried out on this kind of titanium alloy (TC18). The results of tests show that the material removal rate of insert KC522M is the highest, but its tool life is shorter compared with insert SANDVIK 4240. The material removal rate and tool life of insert YD201 do not draw the attention because both of them are relatively low. The abrasion speed of insert SANDVIK 4240 is slow and the efficiency is high, so it is ideal for machining titanium alloy (TC18). In addition, the optimal machining parameters of insert SANDVIK 4240 for milling titanium alloy (TC18) were also given in this paper.

Abstract: In a product structure composed of different parts, sub-assemblies and/or assemblies, different constituents have their particular role in overall product function. Modular product design enables designing instances of a product suitable for different applications with minor design changes in certain parts or systems and plays an important role in product customization. On the other hand, product geometry and functional parameters are related with each other and appropriate selection of the former can ensure fulfillment of the latter. In this research, a micro-level methodology for product customization by designing part instances in a modular design is presented. The approach emphasizes on achieving product functional parameters while controlling respective critical geometric parameters. In this regard, product geometric and functional parameters relationships are established using regression analysis of results from finite element analysis (FEA) simulations of product process model. The research is applied on a machine structure from industry and the results show success and effectiveness of the proposed methodology.