Key Engineering Materials Vols. 426-427

Abstract: From the laser welding actual process, the welding heat source model of laser welding process was established, that is, superposition heat source. According to the knowledge of thermodynamics, the establishment of a welding process, the mathematical model of temperature distribution of laser welding process was obtained by laser welding heat source. Finally, the finite element simulation of welding temperature distribution was used. The simulated results were compared with the analytical results of mathematical model of temperature field, it was proved consistent between simulated results and analytical results, at the same time it can account for the correctness of the mathematical model of temperature field.

Abstract: This paper presents initial work with the application of basalt fiber (BF) in the field of reinforced cement composites. Effect of BF on mortar drying shrinkage, mechanical prosperities and bond performance were studied. The results showed that adding of BF reduced markedly dry shrinkage of mortar especially at early ages. BF mortar had a greater compressive and flexural strength at early hydration period，but had a little less strength at the age of 28-days than mortar without fiber. Four point bending tests shows that addition of BF increased effectively toughness of mortar specimen at 28-days at the same loading, but had not a remarkable effect on fracture strength. A good bond was observed between BF and mortar matrix interface zone by SEM in early ages and there was debonding phenomenon between BF and mortar matrix in the long-term ages.

Abstract: Based on the analysis of the belt misalignment of the metal V belt CVT, the reason of the belt misalignment has been discussed. In order to control the misalignment, an electro-hydraulic control system has been designed. After deeply analyzing the structure and principle of the electro-hydraulic control system, the mathematical model of the electro-hydraulic control system has been established. Being varieties of the working situation of car and the non-linearity of the electro-hydraulic control system, A Fuzzy PID algorithm has been designed. Then the simulation of the belt misalignment has been conducted, and the simulation results show that the electro-hydraulic control system and the fuzzy controller could not only control ratio, which had a higher accuracy of the stable state and a stronger robust of the driving condition, but also eliminated the belt misalignment, improved the dynamic performance of the metal V belt CVT.

Abstract: Cut-in disrepair of milling inserts are closely related to dynamic equation of cut-in contact. According to the problem of serious cut-in disrepair, dynamic equation of cut-in contact for the waved-edge milling insert with 3D complex groove is studied. Rake face function of 3D complex groove waved-edge milling inserts is founded. Rake face equation of 3D complex groove inserts is founded. Rake face motion equation of 3D complex groove inserts is deduced. Appearance equation of workpiece machining region is deduced. Contact line (LM) equation is deduced, which is the contact line between rake face and workpiece cut-in side surface when rake face moving. Intersection line (C1D1) equation is deduced, which is the intersection line of cutting surface and side surface of workpiece. All the production above are the theory foundation for further researching the relationship between the cut-in style and cut-in disrepair, cut-in style optimization, 3D complex groove insert optimization.

Abstract: Based on the analyses of the yarn tension and the mathematical model of the magnetic powder brake, the digital simulation of the yarn tension fuzzy control system was performed by using MATLAB Simulink. The relationship between the structure parameters and the system dynamic performance was then obtained, and the system scheme was justified.

Abstract: The surface of 304 stainless steel was processed by laser shock wave, its surface micro-structures were observed with SEM, and residual stresses on its surface were measured with X-ray diffraction (XRD) stress tester, and the production mechanism of residual stress was analyzed. The experiment of stress corrosion in 25% NaCl aqueous solution was finished, the crack sensitivity of stress corrosion in NaCl aqueous solution was researched, and the effects of LSP on stress corrosion resistance were analyzed. The results shown that the refined hardened-layer is acquired on the surface of 304 stainless steel by LSP, and compressive residual stress has greatly increased, which improve availably the performances of stress corrosion resistant. The time of appearing cracks is inverse ratio with compressive residual stress, and LSP decreases effectively its stress corrosion cracks.

Abstract: Single screw pump is a kind of inside engaged biased rotation volume pump, which is widely applied in a number of major fields of the national economy. The key components are the rotor and the stator with complex spiral surface, which are meshing with each other. The machining accuracy of them makes effect on the working performance of single screw pump directly. In this paper, the operation principle of the single screw pump with large lead and multiple heads was represented, and the mathematical model of the rotor and the stator was established. The three-dimensional models of rotor and stator of single screw pump were put into effect with three-dimensional modeling software UG. This study has laid a theoretical foundation to the research of new manufacturing technology of the spiral curved surface and the development of the corresponding machine.

Abstract: Attapulgite-zeolite composite nano-structure adsorbent was manufactured using natural attapulgite and zeolite. The obtained adsorbent was characterized by scanning electron microscope, energy dispersive X-ray spectrometer and mercury porosimeter. After elementary characterization of this adsorbent, batch tests were carried out to examine its removal mechanism of phenol. The influence of pH, contact time and initial phenol concentration were investigated. The pH variation studies showed that the optimum pH for adsorption of phenol was found to be 7. Adsorption equilibrium attained within 1 h time. The adsorption process followed pseudo-second-order kinetic model. Adsorption isotherm studies showed that Langmuir model fitted the experimental data better than Freundlich model. The attapulgite-zeolite composite nano-structure adsorbent in this study shows very good promise for practical applicability of phenol removal from aqueous solution.

Abstract: This paper is devoted to the static friction torque of electromagnetic clutch. The torque maximization is also investigated by optimizing the geometrical shape of armature. For the purpose of designing and optimizing electromagnetic clutch, torque prediction is a very important factor. We construct an axi-symmetric FEM model to analyze static friction torque and use a torque tester to evaluate real torque. In this work, analytically predicted torque is compared with the experimental one to discuss the rationality of numerical process. The analytical result agrees well with experimental data, which proves the validity of the mathematical process. Through optimization of the shape of armature, we also improve the static torque of electromagnetic clutch about 30%.

Abstract: People are in dire need of knowing whether the workpiece is satisfactory after laser forming while using the technology of laser forming with thermal stress. In order to solve the difficult problem of how to evaluate the quality of laser forming with thermal stress, surface quality evaluating indexes have been studied firstly; surface defects, surface roughness and surface association mechanical property (such as surface hardness, surface constitution, surface residual stress) are considered as primary measuring indexes of laser forming quality; the internal quality of laser forming is rested with the quality of forming area. Surface defects and their methods of calibration, surface roughness and its method of measurement, surface association mechanical property and its methods of measurement are introduced respectively. In the meantime, how to establish the quality evaluating system of laser induced thermal stress forming work pieces has been discussed, the work should be carried out after conforming to evaluation system, evaluation indexes and evaluation criterion.