Advanced Materials Research Vols. 1061-1062

Abstract: The composite beam is efficient and easy for construction. But shear connector is needed for the composite action. This research developed SPC beam in order to reduce the shear connector with utilization of mechanical bond by the cross sectional shape. The flexural behavior of SPC beam was evaluated through two point loading test.

Abstract: Asphalt mixture was simply treated as a two-phase composite, in which coarse aggregates are embedded into asphalt mastic matrix. According to the elastic-viscoelastic correspondence principle, an elastic micromechanical method is extended for predicting viscoelastic properties of asphalt mixture, which is simply treated as elastic coarse aggregate inclusions periodically and isotropically embedded into viscoelastic asphalt mastic matrix. The Burgers model is adopted for characterizing the matrix mechanical behavior, so that the homogenized relaxation modulus of asphalt mixture in compression creep is derived. After a series of uniaxial compression creep tests are performed on asphalt mastic in different stress conditions in order to determine the matrix constitutive parameters, the presented framework is validated by comparison with the experiment, and then some predictions to uniaxial compression creep behavior of asphalt mixture in different stress conditions are given.

Abstract: Converting the viscosity of an incompressible nonlinear viscous fluid to the proportional constant of the flow rule of Mises material, the melt, the mushy state, and the solidified in twin-roll casting were able to be regarded as an incompressible nonlinear thermo-viscous material. Recently, this thermo-mechanical process and the shrinkage fit of a roll have been numerically modelled. Some of these models are reviewed and discussed in the present study.

Abstract: The purposes of this research are to explore the baseplate and actuator arm deformation which effect to the gram load which occur in the ball swaging process, the main component determining quality of assembly the head stack assembly with the actuator arm. By shooting a ball though the base plate, the component located on the head stack assembly, the base plate plastic deformation takes place and it in expand in radial direction. The base plate then adjoins with the actuator arm. Using the finite element method to reproduce the ball swaging process, we repeated to study effect of the swage press clamp and velocity. The study done by creating the three dimensionals finite element model to analyze and explain characteristics of the baseplate and actuator arm deformation which effect to gram load which effect to the ball swaging process.

Abstract: High-speed cutting technology has become an important development direction of modern NC machining technology, but the existing equipments are often not suitable for high speed machining. An effective method is proposed in view of the cutting heat in cutting process, by introducing chiller to the existing cooling system, the coolant temperature decrease, tool and workpiece temperature can also reduce, so general machining center can achieve cutting speed as quickly as possible.

Abstract: An actual case of PTH fracture after soldering process was studied. By means of cross section analysis using metallography microscope and SEM, together with thermal analysis results, root cause of PTH fracture was concluded that a high density of twin copper weakened the mechanical strength so seriously that PTHs could not undergo thermal stress from soldering process, and higher CTE was attributed to an accelerative factor. Moreover, it is recommended to enhance current density properly and make sure the effectiveness of electroplating additives to prevent twin copper by theoretical analysis.

Abstract: GH169 superalloy steel was coated by hot-dipping in a molten aluminum bath, and then diffusing annealing at 950 °C for 2h. The cyclic oxidation behaviors of the hot-dipped aluminized steel and GH169 were tested at 900 °C for 24 cycles using resistance furnace. Morphology of surface and cross-section, element distribution of the oxide scale were characterized by SEM and EDS. The results showed that protective Cr₂O₃ and Al₂O₃ oxide scales were formed on GH169 and aluminized steel after 24 cycles, respectively. The inner oxidation was found on GH169 after 24 cycles. It was composed of surface Al₂O₃ oxide film, outer Al-rich layer scattered with NiAl phase, and inner NiAl layer on aluminized steel after 24 cycles at 900°C.

Abstract: The machine realized the function of positioning and calibration by using Siemens MM440 and absolute encoder. It accomplished the structured program and optimized HMI screen, the forming machine can produce all kinds of different diameter welded pipes without changing rollers.

Abstract: This paper conducted a theoretical study on the generation and transformation mechanism of α-Fe₂O₃ in the oxide film and an experimental verification of the presence of it. Firstly, the electrochemical process of the generation and transformation of α-Fe₂O₃ in the oxide film was analyzed, followed by the measurement of the content of it in the oxide film using X-ray diffractometer.

Abstract: The effect of the outer chamfered angle at the free end of adherend on the stress distribution in weld-bonded single lap aluminum joint was investigated using elasto-plastic finite element method (FEM). The results from the numerical simulation showed that the peak stress along the bondline at the end of lap zone decreases when the adherend is chamfered on the outside and it is decreased greatly as the chamfer angle decreased. Compared to the results from the normal joint, a 15 degree chamfer angle may be appropriate to optimize the stress distribution in the weld-bonded single lap aluminum joint.