Advanced Materials Research Vol. 980

Abstract: The application of single front wheel brake can yield large deceleration on underbone motorcycle. However, the motorcycle motion potentially exposed to the nosedive effect during this application. Therefore, in order to avoid this issue, the application of concurrent brake are required. Hence, this research was carried out to understand the basic braking performance for underbone motorcycle and elucidate the influenced of concurrent braking application involving the front and rear brake component. A theoritical study was carried out in this work through the derivation of motion equation for underbone motorcycle. The preliminary results showed that the total brake force and the brake force component acting on the front wheel had increased linearly with its deceleration intensity. Further study showed that in order to achieve higher safety range, the brake force applied on the front wheel should be at least 70% higher than the rear brake force intensity. This is probably due to the weight transferred condition during the underbone motorcycle braking.

Abstract: The medium flow of control valve is a typical complex unsteady flow, the internal flow is very unstable which leads to trim or body with vibration of different amplitude, therefore, control valve has been a failure-prone components in the turbine inlet steam system. This paper take the new valve as the research object, by computational fluid dynamics (CFD) software, the numerical simulation of the internal steam steady state flow field of valve normal work a typical opening in the process of opening is made, and obtain the internal flow field visualization distribution and flow characteristics of control valve. Extract unstable place pressure pulsation of the flow field, get the pulse frequency, and provide the basis for the design, optimization and application of low vibration noise control valve.

Abstract: Flow assurances in deep water pipeline have received greater attention in oil and gas industry in order to meet the optimum production of hydrocarbons. However, existence of free water in the gas pipeline decreases production output and increases operational cost and time. Alternatively, anew supersonic subsea compact wet gas separator is design to remove free water from gas transmission pipeline. The key parts of the new design separators is the nozzle.The performanceof supersonic flow is highly related on the design of the nozzle. Therefore, the objective of this paper isto find correlation between the angle of the nozzle against separator flow performance, namely velocity. From the analysis done, it can be concluded thatat nozzle angle of 15°, maximum velocity is achievedthus producing supersonic flow.

Abstract: Identification of the mechanical properties of high-strength steel using digital image correlation. In this paper an experimental procedure to identify the plastic behaviour of sheet metals up to large strains using full field measurement is presented. The tests were conducted on notched specimens. This geometry generates a heterogeneous strain field which was measured during the test using a digital image correlation system. The advantage of using a heterogeneous strain field in the identification procedure is that a complex state of stress-strain can be analyzed at the same time and much more information can be obtained in a single test. On the other hand, the stress field cannot be directly computed from the test and a suitable identification procedure must be developed. Here, the virtual fields method (VFM) adapted for large strains and plasticity was used to identify the hardening behaviour and the anisotropy of the material. The values obtained with the VFM were compared with the results from a standard identification made using uniaxial tensile tests.

Abstract: This paper deals with FEM analysis of six models that represents human cortical bone, cast TiAl6V4 alloy and porous TiAl6V4 with different pore diameters. Reliable data for the simulations were achieved by meta-analysis that consisted from 53 scientific works. Strain value was chosen with a respect to the frequent daily activities such as walking. According to the FEM analysis of presented models von Mises stress values and stress concentration factors were similar for human cortical bone and porous TiAl6V4.

Abstract: This paper presents the test results of proposed grouted sleeve connections under increasing tensile load. The objective of this research was to investigate splice connections that could provide tensile strength similar to the full tensile strength of the connected rebars. The parameters varied were splice types, splice length and rebar embedment length. The performance of the splice connection was evaluated based on the load-displacement, ultimate load, displacements and failure modes. The results show that the strength of splice connection depends on the bond strength between sleeve-to-grout and grout-to-rebar; the tensile strength of spliced steel bars and also the tensile strength of sleeve. It is observed that when the grout compressive strength is more than 60N/mm² and bar embedded length is at least 10 bar diameter, the splice connection in BS series is able to provide full tensile strength of the connected rebars.

Abstract: UltraHigh Performance Fiber Reinforced Concrete (UHPFRC) exhibits remarkable mechanical performance, which can allow to reduce the cross-section of structural members. However,a problem involving UHPFRC isthe likely tendency to crack at early age, due to autogenous and plastic shrinkages, caused by the very low water-to-binder ratio adopted. Therefore, this experimental work intends to detect the effectiveness of a possible solution for reducing the risk of shrinkage cracks in UHPFRC, by adding to the mixture a suitable combination of expansive and shrinkage reducing agents.Compressionand bending testswere carried out up to28 days of curing. Free drying shrinkage strains were evaluated up to 56 days of exposure to 50% relative humidity. The experimental results obtained by using expansive and shrinkage reducing agents were extremely encouraging in termsof free dryingshrinkage reduction, and even surprising in terms of flexural behaviour.

Abstract: Self-leveling lightweight mortars were developed to attain good workability, sufficient compressive strength (at least 5 MPa after 28 days of wet curing), and low specific weight (less than 1100 kg/m³), as well as low thermal conductivity (lower than 0.3 W/m∙K). The attention was also focused on the sustainability of this construction material, which was improved by using in the mixture both glass reinforced plastic (GRP) industrial by-product as filler replacing limestone powder, and recycled aggregates replacing natural sand. GRP is a composite material made of glass fibres dispersed in a resin, usually polyester, widely used in several fields from building to furniture factory to boatyard. The recycled aggregates used were alternatively either wooden waste or polyurethane waste particles. Concerning wooden waste, they are produced by cutting, drilling and milling operations, where wood is removed from a finished product; they are sawdust and offcuts often collected in filter bags or dust collectors. On the other hand, the polyurethane waste particles were obtained as a rejection of a factory producing rubber soles for the footwear industry. The influence of GRP filler and waste particles on fresh mortar workability, compressive and flexural strength of hardened mortar, as well as on its thermal conductivity was examined. An optimization of the mortar mixture proportions was carried out by suitably varying the dosage of the ingredients. The experimental investigation showed that both the material unit weight and its thermal conductivity resulted strongly reduced, thus indicating a high and promising potential for future developments.

Abstract: This paper describes an experimental investigation for determining the damage modes under low energy impact-fatigue of sandwich panels consisting of aluminum skins supported by honeycomb core made of aluminum. Square samples of 125mm by 125mm sides and 10mm thickness (skin of 0.6mm and 8.8mm of core) were subjected to impact fatigue loading using a testing machine at four different energy levels (2J, 3J, 5J and 7J). The square plates are clamped in a fixture system over a 100mm diameter hole. Three different diameters of impactor head (15mm, 25mm and 35mm) are used to study their influence on life duration of the sandwich plates. Results showed that damage area at impacted face and propagation of multi-cracks at rear face are greatly affected by energy level and impactor diameter.

Abstract: In order to address the problem of stiffness and mechanical properties, a micromechanical approach for the prediction of the overall modulus of nanocomposites (Nylon-6/nanoclay/silica) using a self-consistent scheme based on the double-inclusion model and taking into account the different morphologies exfoliated or intercalated of the nanoparticles. Self-consistent approach that is used in our calculations was explained after reviewing the inclusion of Eshelby, in particular the double inclusion and while considering also the effect of constrained region, modeled as an interphase around reinforcements. Namely, polyamide 6 reinforced with clay platelets and silica particles. Several parameters on the Young's modulus of the composite were studied to see the effect of having mixed two or three reinforcements in polymer matrix. Finally, we demonstrated the process undertaken for the calculation of elastic constants of the material studied.