Applied Mechanics and Materials Vols. 365-366

Abstract: A chamfering algorithm was put forward to achieve automatic NC programming for chamfering addendum of spiral bevel gears and a NC programming module was developed based on UG/Open through secondary development. Furthermore, a practical example was used to demonstrate the automatic NC code generation process for chamfering addendum according to the preset chamfer surface and its permissible error.

Abstract: Thermoelectric energy harvesting is emerging as a promising alternative energy source for drive wireless sensors in mechanical structure monitoring. Typically, the waste heat from spindle units of machine tools creates obvious potential for thermoelectric generation. However, the problem of power gap between the power level needed by wireless sensor and what thermoelectric generators (TEGs) can provide is likely to arise in the application of thermoelectric generation. Therefore, a power management system (PMS) is needed to accumulate TEG energy first and then drive the load intermittently. This study proposes a power management system to enhance the energy harvesting and usage efficiency using three capacitors. A rotating spindle platform is set up to test the PMS, and the experimental result shows that the proposed PMS worked well when the spindle speed is 3000 rpm.

Abstract: In Shanghai Beihong Vehicular Undercrossing Tunnel project, a new type of hydraulic speed-regulating system, which is variable-frequency pump controlled piston system, was used. It uses variable-frequency technology to adjust rotary speed of driving motor. It can fulfill stepless speed-regulating and has good characteristic of power adaptation and energy-saving. The composition of system and working principle are stated, and mathematical model is derived. Digital simulation results show that the system has good controllability.

Abstract: Simulation method to optimize logistics system was studied. The process of this method were pointed out, which main process were DOE and AVONA. Analysis of automatic sorting system based on this method, the significant factors influencing were renovated, including scheduling strategy and equipment technology, so the system was optimized. Thus draw the conclusion: (1)Simulation modeling showed the operation data of logistics system without conditions in physical testing; (2) Method of DOE and mathematical statistics could be selected optimal schemes and pointed out the significant factors that influence efficiency of the system; (3)Reasonable logistics scheduling strategy and renovating equipment technology of significant factors were the fundamental method to optimize logistics system.

Abstract: Visual landmarks are extensively used in contemporary robotics. There are a large number of different systems of visual landmarks. In particular, fingerprints give us unique identifiers for visually distinct locations by recovering statistically significant features. Therefore, fingerprints can be used as visual landmarks for mobile robot navigation. To create fingerprints we need one-dimensional color panoramas of high quality. In this paper, we consider a method for building the panoramic image using string matching algorithms. In particular, we propose the shortest common ordered supersequence problem.

Abstract: PCD is the combination of diamond particles that are sintered together under high temperature and high pressure conditions in the presence of catalytic metal. Due to its superior properties, this material has been widely used for cutting tool. However, magnitude and direction of residual stress obtained from the fabrication process believe to affect the tool performance during application. Furthermore, high temperature generated by the process might also contribute to the structure alteration that finally reduces the strength of PCD. This paper revealed that the residual stress due to EDL is more dominant in tensile direction which is vice versa to the conventional process. Analysis on the spectrum indicated that there is a relationship between the tensile stress value and the composition of graphite on the Raman laser spot location.

Abstract: The softening point of modified asphalt is an extremely important indicator to evaluate the high-temperature performance; its the temperature of modified asphalt sample emerging shear deformation under the action of certain shear stress according to the specific heating rate. Its found that in the actual construction and testing, different temperature conditions has a larger impact on the softening point of the modified asphalt, which has adverse affect on road construction. This paper studied and researched the influence of temperature on modified asphalt softening point indicators from the different test temperature, including packing compact temperature, scraper temperature in removal of asphalt that above test mode, standing temperature, curing temperature and initial heating temperature before test.

Abstract: Sucrose evaporation technique was applied to prepare porous ceramic scaffolds with multiphasic calcium phosphates. Compositions with Ca/P molar ratios of 1.67 with MgO were synthesized and subjected to a thermal treatment of up to 1050 °C to 1400 °C. The results show that various adjustable biphasic and multiphasic calcium phosphates can be prepared through vaporized filler amounts and controlled sintering temperature. The size of the pores in the final fabricated scaffolds with an interconnected network of pores ranged from several micro- to hundred micrometers of open pores. The phase amount of hydroxyapatite (HA) in the sintering process declined with elevated sintering temperature. The permeability of three-dimensional scaffolds used for tissue engineering was significant because it controlled the rate of cell migration and the diffusion of nutrients and waste products in and out of the scaffold.

Abstract: The oxidation behavior of porous Cu-Ni-Cr alloys containing approximately 5,10 and 15 wt.%Cr, but with a similar Ni content of 35 wt.%, was studied at 650°C in air. The results showed that the oxidation of alloys follows linear law at initial stage and then the parabolic rate law. Continuous external scales of CuO and Cu₂O formed on the alloys. Some internal oxide of were observed. In addition, with increase of Cr content, the oxidation rate decreased slightly.

Abstract: The strain change characteristics of multiaxial fatigue are analyzed under the condition of the combined tension and torsion loading for thin-tube specimen. Based on the principle of multiaxial critical plane approach, a multiaxial fatigue damage parameter is established, which takes account of the effect of not only the maximum shear strain amplitude and normal strain amplitude on the critical plane but also the parameter of non-proportionality. The non-proportionality is the function of loading parameters which is closely contact with the strain change characteristics of multiaxial fatigue and it can indicate the whole material damage. The experiments under the tension-torsion proportional and non-proportional loading were conducted to verify the multiaxial fatigue life model proposed in this paper. The life prediction has a good correlation with the experimental results.