Advanced Materials Research Vols. 532-533

Abstract: The purpose of this paper is to study the effect of high temperature in injection molding process on mechanical properties of the warp-knitted and nonwoven composite fabrics (WNC)used in car interior. Tensile, tearing and peeling properties of WNC fabrics were tested after heat treatment under120, 140,160,180°C respectively. It was found that, after 140°C heat treatment, the breaking and tearing value of these WNC fabrics are lower than others. The results of this study show that this phenomenon is due to the material properties of fabrics. These high temperatures have no much effect on peeling properties of these WNC fabrics. It is concluded that in order to preserve the mechanical properties of these WNC fabrics, the temperature near 140°C should be avoided possibly during injection molding process.

Abstract: The paper presents a reliability-based approach to assess the structural integrality of tubular joints with cracks in aging offshore platforms. Two different fatigue failure models are established respectively according to crack propagation size and equivalent fatigue strength, and the corresponding computing methods of fatigue reliability are proposed. The fatigue stress of tubular joint suffering sea wave load is calculated by spectrum analysis. The numerical examples are given to show the difference between the two reliability models. Considered the influence of inspection and repair, the reliability is updated by two different maintenance schedules. The analysis results can help to work out the optimal inspection planning, so as to prolong the service life for aged offshore platforms.

Abstract: The measurement of blood-plasma absolute velocity distributions with spatial and temporal resolution in vivo is important for research on early stage embryo heart development. We introduce a novel method to measure absolute blood flow velocity based on high speed spectral domain Optical Coherence Tomography (OCT) and applied it to measure velocities on the heart outflow tract (OFT) of a chicken embryo (stage HH18).

Abstract: A novel groove guide mixer was proposed. The key features of this mixer are large dimension and good signal-to-noise performance. The shell of this mixer is made up of a novel waveguide, the groove guide. A planar logarithmically periodic antenna was installed in the guide. It received signals in the guide and transmitted them to the mixer diode. A compact multi-section coaxial filter was arranged to lead the intermediate frequency signal out of the shell. At the end of the mixer, a matched terminator is adopted to absorb millimeter wave signals. One model of this mixer was designed, fabricated and tested at 93.069GHz. It works well on millimeter wave band.

Abstract: Flutter derivative is a significant index of the structure flutter stability. Identifying flutter derivative precisely contributes to the bridge flutter stability analyzing. In this paper, we take a research on the Liujiaxia Bridge in Gansu Province, China. Different flutter derivatives, which were got via segment model vibration tests with different aerodynamic measures, were classified, and made comparison in order to get the law of how different aerodynamic measures effect on the flutter derivative. The results show that, setting central stabilized plate, Build-in deflector, flange plate all affect flutter derivative significantly, which leads to changes in the flutter critical wind velocity of the structure. Setting central stabilized plate above the deck contributes to identify the flutter derivative of the 0° and positive attack angle, while setting central stabilized plate will contribute to flutter derivative identification at negative angles. It will make it difficult to identify the flutter derivative at 0° and -3° if the built-in deflector was set. Wind plate contributes to the identification of the flutter derivative at +3°, however, it will make it harder to identify the flutter derivative at 0° and -3°.

Abstract: A numerical simulation has been performed for subcooled boiling process of high pressure liquid. On the basis of two-fluid model, the RPI model is used to calculate the mass transfer on the heating wall between gas-liquid two phases. The results show there is an obvious turning point on wall temperature along with flow direction，which demonstrates the onset point of subcooled boiling according to the variation of wall temperature. The fluid velocity isn’t in linear increase, which increases gradually at first and then increases sharply, which is the similar with that of void fraction. The gas-phase velocity is higher than that of liquid-phase and the difference increases gradually along with flow direction. The variation of two-phase pressure difference is similar with that of single-phase flow, which is mainly the gravity pressure difference. The study results better meet with experimental data, which verifies the accuracy of computational model.

Abstract: Burden in gas-based direct reduction process is iron ore oxide pellet, which has experienced oxide roasting and cooling before reduction. However, it would be heated again in the reduction process. This may cause much energy waste and adverse effects on reduction process. In this paper, roasted pellets with and without cooling were charged for gas-based reduction respectively. The reduction rate and compressive strength during reduction were studied to reveal the effects of charging methods. Results showed that there is little difference on reduction rate between the two. However, the compressive strength of reduced pellets via thermal charging improves obviously. And nucleation and growth mechanisms of iron crystal grain in gas-based reduction were investigated by optical microscope (Leica DMRXP). The iron crystal nucleuses firstly form at the interface of grains and edge of wustite, and then gradually grow from surface layer to inner core as reduction proceeds. Thermal charging can promote the migration and accumulation of iron crystal grain effectively.

Abstract: Many existing subsoilers in these days often suffer from problems such as insufficient tillage depth, large traction resistance, and high energy consumption. To address these problems, we conduct an analysis on, with the self-excited vibratory subsoiling technology, how to reduce resistance effectively. Based on the analysis, a detailed structural design of subsoiling equipments and experimental study is conducted, in order to increase tillage depth without a substantial addition of power, as required in modern agriculture.

Abstract: This article showed that the research of the process of drilling medical titanium sheet. Internal stress, strain and temperature distribution could not be seen, so based on Finite element analysis software, establishing finite element model of the process of drilling. On the basis of the inspection and studying existing drilling technology, three options were proposed .In view of stress, strain, temperature, and axial force, analyze the process of drilling titanium sheet. The results showed that penetration rate in 1000r/min and feed in 0.04mm/r, twist drill drilling medical titanium sheet is more reasonable.

Abstract: The umbilical tensioner is special equipment for laying pipeline offshore. Paper analyzes the research of umbilical tensioner, calculates the driving torque of the drive device, and designs the overall program of the tensioner structure based on four tracks structure, takes a mechanical check of key components in the actual operating environment. Analyzing the umbilical tensioner has a theoretical significance for the designing. The results show that the mechanical structure is reasonable.