Advanced Materials Research Vols. 875-877

Abstract: Based on evolutionary structural optimization (Abbr. ESO) theory, the mathematical model using for topology optimal design of heat conductive structure is constructed by deleting the elements which temperature gradient is lower .Based on the selecting logic method, the numerical calculating program is developed by using APDL command in ANSYS. The feasibility and universality of this method have been well verified in the numerical calculating examples.

Abstract: Factor to energy of single cut abrasive grain at bar to abrasive processing - as generalized factor of cut, since takes into account and power of cutting, depth, length, and volume of single cut is considered in the article. Each of these factors characterizes the cut on the one hand, but factor to energy of single cut characterizes the nature of cut by abrasive grain as a whole.

Abstract: A multi-junction photovoltaic cell based on group II-VI Cadmium Selenide (CdSe) and Cadmium Telluride (CdTe) with a single layer anti-reflective coating of Silicon Di Oxide (SiO₂) has been introduced. In this paper we have performed a comparison of solar energy absorption of CdSe/CdTe cell with existing single and multi-junction cells. The cell has shown significant photon absorption in the spectral range of 300nm-2000nm with an efficiency of 34.6% under terrestrial AM1.5, 1 sun condition.

Abstract: The static and cyclic failure mechanisms of offshore pipe riser repaired with a designated laminate orientation of carbon/epoxy (C/E) system were studied. The finite element (FE) model takes into account failure mechanisms of the composite sleeve inter-layer delamination, debonding at the steel riser-composite surface interface, and the maximum permissible strain of the repaired riser. Design conditions of the combined static loads (coupled internal pressure, longitudinal tensile and transverse bending) were determined through a limit state analysis [1,2]. The limiting static bending load that causes catastrophic failure under a coupled internal pressure and tensile loadings was determined through Virtual Crack Closure Technique (VCCT). The effects of cyclic bending, mimicking the typical scenarios experienced in pipe riser exposed to dynamic subsea environment, were evaluated and compared against the static conditions. The low cycle fatigue of the composite repair system (CRS) is simulated using a direct cyclic analysis within a general purpose FE program, where the onset and fatigue delamination/disbonding growth are characterized through the Paris Law.

Abstract: There are various methods being used to model and study behavior of electromagnetic (EM) waves in controlled source electromagnetic (CSEM) environment. Sea Bed logging (SBL) is using CSEM technique in detecting and characterizing hydrocarbon bearing reservoirs in deep water areas. It uses a mobile horizontal electric dipole (HED) source called transmitter that transmits low frequency of 0.1Hz to 10Hz, 30m - 40m above sea bed and an array of seafloor electric field receivers. These signals depend on the resistivity structure beneath the sea bed as hydrocarbon is known to have high resistivity value of 30 500 Ωm in contrast to sea water layer of 0.5 2 Ωm and sediments of 1-2 Ωm. Array of seafloor receivers detect EM energy that propagates through the sea and subsurface. Data collected is used for processing and modeling purposes to predict depth of resistive bodies. In this paper, synthetics data generated from developed simulator that is able to replicate SBL environment is compared to synthetics data generated from Computer Simulation Software (CST) and COMSOL software with same parameter setting to study trends between them. Percentage differences between data with hydrocarbon and without hydrocarbon are calculated and comparisons are made. Overburden thickness is varied from 1000m to 3000m (incremented by 500m) at frequency of 0.125Hz. It was found that all the data generated either from simulator, CST software and COMSOL showing the same trends. From these findings it shall conclude that the simulator is a reliable tool to model any sea bed logging environment and predicting present of hydrocarbon reservoir in SBL environment.

Abstract: The fact that it is difficult to establish the mathematical model of metal materials by theoretical study method means that can be done by statistical methods. Happens to, the logistic model is more suitable for this work. This paper tries to establish the model of steel hardenability curve by transforming logistic model without a large number of specimens.

Abstract: This by ratiocinating the theoretical formations of the pressing time of Cylindrical fiberboard and analyzing the relationship between the pressing time and Temperature difference and wood-based radius.

Abstract: There are lots of distributed sources in the process of fatigue crack propagation of the lattice boom, static evaluation of the reliability indicators cannot be satisfied to solve practical engineering problems. The load and fatigue resistance regards as a random process, considers the fatigue failure of the randomness in a variety of factors, the concept of dynamic reliability of the weights index is proposed, models of dynamic reliability of the weights index are built based on the fatigue bearing capacity mode and limit damage degree mode. Fatigue stress experiments comparisons are doing during a crawler crane according to the actual operating conditions and a K-type welded joints prototype. The results show that the dynamic reliability evaluation assessment model is more accurately in the fatigue life evaluation and the method can provide a new assessment method for engineering applications.

Abstract: Porous copper fabricated by unidirectional solidification of metal-gas eutectic can be used to manufacture a special kind of micro-channel heat sink. A three dimensional model is developed to investigate the heat transfer in porous copper heat sink. However the experimental results of heat transfer performance are far less than the simulation results. That is mainly because some of the pores are nonpenetrative. When the simulation model is modified by taking the penetration ratio into account the experimental results are consistent with the simulation results.

Abstract: The technique of adhesively bonded composite patch repair has been successfully applied in pipeline of API X65 components repair and has recently been expanded to commercial pipeline industry. In the present paper, the crack growth behavior of cracked pipeline API X65 repaired with bonded composite patch was investigated. The finite element approach was applied in order to analyses the circumferential crack’s behavior repaired by a carbon-epoxy composite patch. The effects of the properties of the patch on the evolution of the stress intensity factor, according of angle crack tip, were discussed. The adhesive properties were optimized to increase the performance of the repair of structures by such reinforcement. Moreover, a relatively new method was developed to stop the external corrosion and the structurally reinforce steel pipes by external wrapping of damaged sections, using fibre reinforced polymer (FRP) materials. The results indicated that the defect width around the circumference had little impact on the ultimate rupture pressure of the repaired vessel. On the other hand, it was found that the defect width around the circumference was affected by the stress state in the underlying pipe substrate.