Applied Mechanics and Materials Vols. 128-129

Abstract: Magnetically controlled shape memory alloy (MSMA) is widely concerned because of its superior characteristics in the field of functional materials. The application of MSMA materials base on experimental study, thus a comprehensive testing device of MSMA external characteristics is developed in this paper, which can simultaneously measure deformation, pressure, temperature and magnetic field. Experimental and testing device of the instrument are analyzed and designed. The curves between MSMA deformation rate and magnetic field, temperature are obtained with the testing device. The experimental results show the device can conveniently test the external characteristics of MSMA materials.

Abstract: In this research, the FEM models of sealing rings for welding bellows mechanical seals were established by applying both isolation and integral contact method, and the displacement and stress of sealing ring’s were calculated. The result shows that a wedge-shaped was appeared on the seal face under the medium pressure and spring force. It can be seen that the integral contact analysis effectively illustrated that the convergence and divergence of the wedge-shaped deformation will be occurred in the contact face. The researching results provide a theoretical basis for the furthermore analysis of the deformation and frictional wear and structure optimization of sealing rings for welding bellows mechanical seal.

Abstract: Ultrasonic attenuation capacity of porous Al alloy with high specific strength were studied .The results show that it is a light material that have good ultrasonic attenuation capacity between 1 and 8MHz. Ultrasonic attenuation coefficient α of porous Al alloy increases with decreasing pore diameter d ,with decreasing porosity Ps and with increasing specific surface Sv.

Abstract: In order to solve the problem of conversion from the finer level of granularity to the coarser level of granularity, this paper proposes a formal method for Granular structure merging based on category theory. Firstly, it takes the granular structure as the granular object and the granular structure mapping as the granular morphism, then the granular object and the granular morphism compose the granular structure category. Secondly, it uses the granular morphism and the granular pushout to achieve the granular structure merging , then gets the granular structure merging algorithm (GrSM). Finally, the author illustrates the method with the concrete examples, which solves the granular structure merging issue. This method has a solid mathematical foundation and methodology, which is worth further study.

Abstract: The formability of the magnesium alloy sheets is poor at room temperature even though the magnesium alloy sheets are attractive because of their excellent characteristics. Application of pulsating hydroforming is a new and effective method to improve the formability. The effects of the pressure amplitude on the maximum bulging height and minimum wall thickness of the formed parts of AZ31B magnesium alloy sheets are examined using finite element simulations. It is shown that the distribution of maximum bugling height and minimum wall thickness is similar for different pressure amplitude A, and a uniform expansion in bulging region is obtained, the cause of the uniform expansion obtained may be caused by the variation of stress components. The AZ31B sheet has an excellent performance in formability when the pressure amplitude and pulsating frequency are properly selected.

Abstract: Soil has elastic-plastic deformation under vibrating working condition. And the acting force between the soil and the vibrating subsoiler parts is of complication. In order to study the effect of the material acting force to the vibrating subsoiler system kinetics features, this paper establishes the vibrating subsoiler system mechanics model considering material acting force. It adopts numerical integral to answer and analyze this model and verify the correctness of the model through comparison of the simulation data and experimental data. The analysis shows that when the amplitude is between 0.01m-0.02m and the vibrating frequency is between 14Hz-16Hz, the vibrating subsoiler can have a comparatively good performance.

Abstract: Molecular imprinted polymers (MIPs) were synthesized in certain conditions in the experiment when tetracycline antibiotics (TCs), including Oxytetracycline, Chlortetracycline and Tetracycline were used as templates, methacrylic acid as functional monomer, and ethylene glycol dimethacrylate as cross-linker. Oxytetracycline and Chlortetracycline (1:1) were chosen as mixed-templates when the bonding property of the polymer was studied. The results showed that the mixed-templates MIPs had high selection for tetracycline, and were expected to be used as separation materials for the extraction and purification of TCs in animal food.

Abstract: 4H-SiC based semicircular electrode metal-semiconductor-metal (SEMSM), triangular electrode MSM (TEMSM) and conventional electrode MSM (CEMSM) ultraviolet (UV) sensors have been modeled, investigated and characterized with numerical simulator ISE-DESSIS. By comparing with relevant experimental data, the model correctness is verified. The electrical and optical features of these sensors are simulated and calculated to character the effect of the novel electrode on performance enhancement. In contrast to CEMSM device, the SEMSM and TEMSM sensors show an outstanding superiority in terms of higher photocurrent, comparable low dark current and excellent quantum efficiency. At a bias of 30 V, the dark currents of SEMSM and TEMSM sensors are below 3.5 pA and the photocurrents are 20.7 nA and 23.7 nA under 310 nm UV illumination, respectively. Furthermore, the peak responsivity is estimated to be larger than 0.135 A/W, 0.156 A/W at 290 nm and maximum quantum efficiency at 280 nm is 58.8% and 67.7% for semicircular and triangular electrode structure, respectively.

Abstract: In the foundry, it's difficult to measure the level of molten iron in pouring package and the flow of molten iron each pouring during casting control process, which will result in the control problem of over-pouring and under-pouring.So,a new measurement method about molten iron level and dynamic detection of vertical flow rate has been developed in this paper.The method is based on infrared radiation and time intervals under the state of vertical flow rate of molten iron. By analysing the flow rate of molten iron in the casting ladle taphole theoretically, building field experimental device and analysing experimental results, it shows that the proposed iron level measurement and dynamic detection of vertical flow rate based on infrared radiation and time intervals are feasible. And then it lays a foundation for controlling the flow of molten iron.

Abstract: A kind of hydro-pneumatic spring with adjustable stiffness was designed. The two-level stiffness converse each other when oil pressure reach a certain value. A complex nonlinear mathematic model of hydro-pneumatic spring was set up on the basis of comprehensive analysis of it s working principle and structure. Simulation results comparison and theoretical analysis with the test data of bench test showed that the mathematic model is authentic.