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Showing 1 to 20 of 25 for “"Thrust force"”.
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Modeling and experimental investigations of drilling carbon fiber reinforced composites
… model is proposed to predict the critical thrust force at which delamination starts. The model takes into account the thermo-mechanical loads with considering a mixed-mode of fracture that takes place in the delamination area for unidirectional composites. The proposed model has been …
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Force control in flapping foils using in-line motion and passive pitch
… propulsion at the cost of parasitic oscillatory forces. The addition of in-line motion to a flapping foil trajectory can improve the control of the fluid force. Previous work has shown that by actuating the heave, surge, and pitch motions of a foil and iteratively optimizing the results, the lift …
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An experimental and theoretical investigation of the reaming operation
… has revealed that there are three components of force and torque which are developed in a reaming operation. Thrust force and cutting torque which both are constant during a reaming operation are generated as the result of material removal by the chamfer of the reamer. The chamfer section of the …
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Forces generated in high velocity, low amplitude manipulations of both the dominant and non-dominant rib 1 costotransverse joints: a pilot study
Objective: To determine the force/time characteristics of prone rib 1 High Velocity, Low Amplitude (HVLA) manipulations. Conclusions: Preload and peak thrust force closely related to each other and the production of a joint cavitation. No significant differences between the force/time …
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Design and Development of a Novel Soft Valve and Energy-Storage Mechanism for High-Power Underwater Robotic Pulse-Jet Propulsion
… deforming and buckling principles and applying force via a pinch thruster mechanism to achieve a controlled opening. Experimental testing was conducted on the novel valve to evaluate different characteristics of the valve such as shape, material, thickness, and size. Valve characterization …
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Guidance and Control of Autonomous Unmanned Aerial Systems for Maritime Operations
… on the trajectory tracking error are enforced using barrier Lyapunov functions, and a user-defined rate of convergence of the trajectory tracking error is guaranteed by employing a reference model for the trajectory tracking error's transient dynamics. In this control system, the …
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Review of flapping foil actuation and testing of impulsive motions for large, transient lift and thrust profiles
… foils were tested to produce large, transient forces in still water. These swift, onetime strokes take advantage of added mass/inertial effects and large, stably attached vortices to avoid delay due to the realization of a jet wake for propulsion [1]. Previous work has produced trajectories, …
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Dedução do incremento das forças de corte dinâmico ortogonal e sua aplicação para previsão da carta de estabilidade, num modelo simplificado de máquina operatriz
… the theoretical deduction of increment in the thrust and main cutting forces during dynamic orthogonal cutting process for continuous chip, taking iinto account that these forces are functions of two variables, namely the chip thickness and the shear angle. The dynsmic variation of the shear …
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Reduction of unsteady underwater propeller forces via active tail articulation
… as a means to reduce unsteady propeller forces and by extension, noise due to stator wake blade interaction. This study is experimental in nature and testing was completed in a closed-channel water tunnel at the Naval Undersea Warfare Center in Newport, RI. A propeller-force measurement …
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Simultaneous machining of aerospace structural materials using poly-drills
… drilling output parameters, such as the thrust force, chips formation, post-drilling tool conditions and hole metrics including surface roughness, deviation of hole from the nominal size, circularity, cylindricity, perpendicularity, and burrs formation under dry conditions. Moreover, the …
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Unsteady Aerodynamic/Hydrodynamic Analysis of Bio-inspired Flapping Elements at Low Reynolds Number
… which makes it challenging to generate lift and thrust. Overcoming these challenges means utilizing non-conventional lifting and flow control mechanisms generated by unsteady flapping body motion. Understanding and characterizing the aerodynamic phenomena associated with the unsteady motion is …
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Examination of excavation chamber pressure behavior on a 17.5 m diameter earth pressure balance tunnel boring machine
… inputs, and key operating parameters such as thrust, cutterhead and screw conveyor torque, cutterhead and screw conveyor rotation speeds, etc., were studied in great detail to determine what parameters influenced chamber pressures and how. The results of detailed EPBM data analysis supported …
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The Design and Experimental Optimization of a Wingtip Vortex Turbine for General Aviation Use
… drag and wake turbulence) and also produces a thrust force component. The WVT also has the advantage of extracting the rotational energy of the vortex to turn a generator, which could be used to power onboard applications during normal or emergency flight operations. A 1/4-scale model of a …
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Extended Momentum Model for Single and Multiple Hydrokinetic Turbines in Subcritical Flows
… Free Surface Actuator Disc Theory to yield drag forces and interference factors from a series of two porous discs in open channel flows. The new model includes blockage ratio and Froude number as independent variables, which are inferred in advance to yield a single solution in the prescribed …
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Aero-propulsive characteristics of an overwing distributed electric propulsion system with vectored thrust
… ducted fan system was tested with varied thrust angles achieved by deflecting the fan exit flow direction. The DEP system was comprised of five electric fans mounted on the upper surface of the airfoil trailing edge. The electric ducted fans were sized with a diameter-to-chord ratio of …
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Experiments in electroaerodynamic propulsion
… (EAD) propulsion, which produces a thrust force by electrokinetic acceleration of ions in air, is a proposed method of electric airplane propulsion that is solid-state, nearly silent, and produces no direct combustion emissions Recent work suggested that EAD-propelled aircraft are …
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Construction and performance of an inverted pendulum thrust balance
… thesis was to devise a means of profiling the thrust of the MIT Space Propulsion Lab's (SPL) Diverging Cusped Field (DCF) thruster and, more generally, other thrusters of similar size and thrust levels. The former SPL thrust stand, which had been used to characterize the BHT-200 engine, was not …
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Design and assessment of a super high speed, hybrid hydrofoil/SWATH crew boat
… due to the trim moment produced by the turbo-jet thrust force. The feasibility assessment phase in foil borne mode confirmed the static stability of the vessel and good seaworthiness in waves. It is recommended that future work be conducted with CFD simulations in unsteady conditions, to obtain a …
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Millipede-Inspired Locomotion for Rumen Monitoring through Remotely Operated Vehicle
… ability to handle large frictional and viscous forces in the direction of motion performing submerged burrowing-like action. The rumen environment consists of varying stiffness content with different fluidic concentration across the layers, reaching high viscosity and densities similar to wet …
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Development of Hardware and Efficient, Robust Control Algorithms for a Nanosatellite Reaction Control System
… actuators which generate external control forces and torques, such as reaction control thrusters, are required. Such actuators are also required when performing precise orbit adjustments in missions involving rendezvous and docking operations. This study addresses the relative lack of …
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