BUCKLE PROPAGATION OF SANDWICH PIPES UNDER EXTERNAL PRESSURE

Buckle propagation of local collapse appearing in the damaged pipes is one of the failure modes that are of particular interest for deepwater application. The local collapse can propagate along the pipeline for long distances in both directions when the external pressure magnitude is up to the propagation pressure. In this paper, the buckle propagation pressure of sandwich pipes (SP) with different material properties and geometric characteristics is investigated by numerical simulation using Python programming language based on general finite element code. The results of the pressure history data obtained are verified by comparing those published previously. The effect of material properties, geometric characteristics and adhesion conditions on the propagation pressure are analyzed.

Design and Development of a Commercial Hair Trimmer Cleaner Unit

A product design and development process has been adopted to study and improve the performance of unit cleaner system. A hair trimmer with liquid detergent in cartridge is fixed as a cleaner system to design and analyse. The 3D model of the system is designed with NX CAD software. The modification is cartridge unit is made on counter face to increase the turbulence of the fluid in the wash zone. The file has been extracted and imported in LS Dyna for meshing the model for detergent liquid flow analysis. The velocity vector and pressure magnitude of the fluid flow is analysed through a StarCCM+ higher fluid analysis software. The input process condition of the pump in cartridge assemble unit has a speed 2000 rpm and velocity of the liquid as 1 m/s. From the analysis, the suction pressure noticed at the pump zone is 950 Pa and the discharge of fluid in the pump is 850 – 900 Pa at wash zone. Difference in fluid velocity found decreased and it is in the range of 0.8 to 0.95 m/s. The predominant factor in the design is alternate openings in case baffle has increased the turbulence in pressure and the velocity of the fluid found same.

Computational Modeling of Ultrasound C-Scan Imaging Using Transmitted Signal Peak Density

Ultrasound measurement is a relatively inexpensive and commonly used imaging tool in the health sector. The through-transmission process of ultrasound measurement has been extensively evaluated for detecting abnormalities in tissue pathology. Compared to standard imaging parameters such as amplitude and time of flight, quantitative ultrasound parameters in the frequency domain can provide additional details regarding tissue microstructures. In this study, pressure magnitude or amplitude variation in the frequency spectrum of the received signal was evaluated as a potential imaging technique using the spectral peak density parameter. Computational C-scan imaging analysis was developed through a finite element model. The magnitude variation in the received signal showed different patterns while interacting with and without inclusions. Images were reconstructed based on peak density values that varied with the presence of solid structure. The computational results were verified with the experimental C-scan imaging results from the literature. It was found that magnitude variation can be an effective parameter for C-scan imaging of thin structures. The feasibility of the study was further extended to identify the structure’s relative position along with the sample depth during C-scan imaging. While moving the structure in the direction of the sample depth, the pressure magnitude variation strongly followed a second-degree polynomial trend.

DISCHARGE CHARACTERISTICS OF COMBINED LOW ENERGY ION SOURCE – MAGNETRON SPUTTERING SYSTEM

The discharge characteristics of a new combined low energy magnetron-ion-source sputtering system are presented. The ignition curves, current-voltage characteristics of the system in dependence on gas pressure, magnitude and topology of magnetic field have been researched both for autonomous operation of the planar magnetron discharge and Hall type ion source in plasma mode and for their combination. Spatial distributions of ion current are also presented.

Comparative assessment of the inline and branching design strategies based on the compound technique

The inline or branching water hammer control strategies, which are based on the insertion of compound plastic short-penstock or inline section at the transient-induced region of main pipes, illustrated a promising ability to upgrade steel pipe-based hydraulic systems concerning the extension of admissible pressure level. In this respect, prior results suggested that the specific layout utilizing an (HDPE–LDPE) compound short-penstock (where the (HDPE) sub-short-penstock is attached to the main steel pipe and the (LDPE) sub-short-penstock corresponds to the short-penstock dead-end side) provided significant attenuation of pressure magnitude. Concurrently, recent studies concluded that the (HDPE–LDPE) compound short-section-based inline strategy provided substantial attenuation of pressure magnitude. However, these strategies illustrated a drawback relying on the expansion of the period of pressure wave oscillations. Accordingly, this study assessed and compared the capacities of the compound technique concerning the trade-off between the magnitude-attenuation and the period-expansion of pressure wave oscillations. The findings of these analyses showed that the (HDPE–LDPE) compound short-penstock particular setup of the branching strategy allowed the best trade-off between the attenuation of magnitude and the period expansion of pressure wave oscillations. Furthermore, results showed the competitiveness of the latter upgrading strategy as compared to the (HDPE) or (LDPE) main pipe-based renewed hydraulic systems.

Design and application of PneuNets bending actuator

Purpose The purpose of this study is to propose an improved design of PneuNets bending actuator which aims at obtaining larger deflection with the same magnitude of pressure. The PneuNets bending actuator shows potential application in the morphing trailing edge concept. Design/methodology/approach Finite element method is used to investigate the characteristics of the improved design bending actuator. Multiobjective optimal design of the PneuNets bending actuator is proposed based on the Gauss process regression models. Findings The maximum deflection is obtained when the height of the beams is smaller than half the height of the chambers. The spacing between chambers (beam length) has little effect on the deflection. Larger spacing could be used to reduce the actuator weight. Originality/value With the same pressure magnitude, the deflection of the improved design bending actuator is much larger than that of the baseline configuration. PneuNets bending actuator could increase the continuity of the aerodynamic surface compared to other actuators.

Decompression Analysis of Multi-Layered Barrier Flexible Pipes Under Catenary Configuration

Periodic shutdowns, which decompress service pressure down to atmospheric pressure, are common in offshore flexible pipe systems. In high pressure and high temperature operations, the use of multi-layer barrier flexible pipes is also common. A multi-layer barrier usually combines inner sacrificial and pressure sheaths and, under certain circumstances, the annular gap between these sheaths is filled with fluid. When this fluid is trapped in this gap, which may occur due to a rapid decompression on shutdown operations or an accidental opening of an upstream valve, the flexible pipe system may fail. The trapped fluid tends to be released slower than the fluid that transiently flows under the bore thus generating a differential pressure, which is function of the rate of decompression, and may induce the collapse of the inner carcass. Therefore, the assessment of the magnitude of this differential pressure is crucial to prevent safe decompression rates. This article describes a numerical model, based on finite differences, to predict the differential pressure magnitude for risers in catenary configurations. The model is developed considering fundamental fluid dynamics principles, such as the conservation equations, for a one-dimensional geometry. The results are compared to previously published literature data for a given 4” flexible pipes under two different geometric configurations (horizontal and catenary). The results from the proposed model agreed quite well with those from a previous proposed approach for horizontal configurations, while the catenary configuration analyses evidenced the impact of the gravity parcel on the differential pressure between the pressure sheath and the bore of the pipe.

Numerical Analysis of Innovative Wind Booster Configurations for Vertical Axis Wind Turbines

Vertical Axis Wind Turbines has been looked upon by researchers as a potential avenue for power generation at domestic level. The Coefficient of Power of Vertical Axis wind Turbine has its limitations mentioned by Betz theory. In this paper three configurations viz one stage, two stage and three stage Wind booster has been designed, modelled and numerically analyzed. A Multistage concept of flaps has been used in wind booster so that wind velocity may increase during each stage. The performance of turbine is assessed by wind booster for Flow velocity, Pressure. For Numerical analysis SST K-epsilon turbulence model has been used. From the analysis it is found that, the two stage wind booster velocity and pressure magnitude range is superior as compared to other two configurations.

A Comparison Study on the Effect of Various Layered Sandy Soil Deposited on Final Settlement under Dynamic Loading

The foundation is expansion in base of column, wall or other structure in order to transmit the loads from the structure to under footing with a suitable pressure with soil property. There are two conditions to design foundation: 1. The stress is applied by footing on soil is not exceeded allowable bearing capacity ( ). 2. The foundation settlement and differential settlement are due to applied loads are not exceeding the allowable settlement that based on the type and size of structure, the nature of soil. Rigid square machine footing with dimension 200*200 mm with two types of relative density (50 and 85)% medium and dense density respectively are using in this study in different 28 models to show the effect of layered sandy soil in two configuration, medium-dense MD and dense-medium DM on the final settlement in magnitudes and behaviors under dynamics loads applying with different amplitude of loads (0.25 and 2) tons at surface with amplitude-frequency 0.5 Hz with explain the effect of reinforcements material on reduction the magnitude of settlement. The final results appeared with respect to the specified continuous pressure and the number of loading cycles, the resulting settlement from the dynamic loading increases with the increase in the dynamic pressure magnitude, the variation on densities of layered soil effect on the amount of settlement due to different loads applied...

Buckle Propagation of Sandwich Pipes Under External Pressure

Buckle propagation of local collapse appearing in the damaged pipes is one of the failure modes that are of particular interest for deepwater application. The local collapse can propagate along the pipeline for long distances in both directions when the external pressure magnitude is up to the propagation pressure. In this paper, the buckle propagation pressure of sandwich pipes (SP) with different material properties and geometric characteristics is investigated by numerical simulation using Python programming language based on general finite element code. The results of the pressure history data obtained are verified by comparing those published previously. The effect of material properties, geometric characteristics and adhesion conditions on the propagation pressure are analyzed.