scholarly journals Torque for an Inertial Piezoelectric Rotary Motor

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Jichun Xing ◽  
Lizhong Xu
Keyword(s):  
Kinetic Energy ◽  
Dynamic Equation ◽  
Strain Energy ◽  
Operating Performance ◽  
Theory Analysis ◽  
Peak Voltage ◽  
Motor Torque ◽  
Excitation Signal ◽  
Driving Torque ◽  
Rotary Motor

For a novel inertial piezoelectric rotary motor, the equation of the strain energy in the piezoceramic bimorph and the equations of the strain energy and the kinetic energy in the rotor are given. Based on them, the dynamic equation of the motor is obtained. Using these equations, the inertial driving torque of the motor is investigated. The results show that the impulsive driving torque changes with changing peak voltage of the excitation signal, the piezoelectric stress constant, the thickness of the piezoceramic bimorph, and the rotor radius obviously. Tests about the motor torque are completed which verifies the theory analysis here in. The results can be used to design the operating performance of the motor.

scholarly journals Double-Deck Metal Solenoids 3D Integrated in Silicon Wafer for Kinetic Energy Harvester

Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 74
Author(s):  
Nianying Wang ◽  
Ruofeng Han ◽  
Changnan Chen ◽  
Jiebin Gu ◽  
Xinxin Li
Keyword(s):  
Kinetic Energy ◽  
Power Density ◽  
Energy Harvester ◽  
High Efficiency ◽  
Vibrational Energy ◽  
Average Power ◽  
Wafer Level ◽  
Peak Voltage ◽  
Silicon Mold ◽  
Casting Technique

A silicon-chip based double-deck three-dimensional (3D) solenoidal electromagnetic (EM) kinetic energy harvester is developed to convert low-frequency (<100 Hz) vibrational energy into electricity with high efficiency. With wafer-level micro electro mechanical systems (MEMS) fabrication to form a metal casting mold and the following casting technique to rapidly (within minutes) fill molten ZnAl alloy into the pre-micromachined silicon mold, the 300-turn solenoid coils (150 turns for either inner solenoid or outer solenoid) are fabricated in silicon wafers for saw dicing into chips. A cylindrical permanent magnet is inserted into a pre-etched channel for sliding upon external vibration, which is surrounded by the solenoids. The size of the harvester chip is as small as 10.58 mm × 2.06 mm × 2.55 mm. The internal resistance of the solenoids is about 17.9 Ω. The maximum peak-to-peak voltage and average power output are measured as 120.4 mV and 43.7 μW. The EM energy harvester shows great improvement in power density, which is 786 μW/cm3 and the normalized power density is 98.3 μW/cm3/g. The EM energy harvester is verified by experiment to be able to generate electricity through various human body movements of walking, running and jumping. The wafer-level fabricated chip-style solenoidal EM harvesters are advantageous in uniform performance, small size and volume applications.

scholarly journals Mathematical models of supersonic and intersonic crack propagation in linear elastodynamics

2021 ◽  
Author(s):  
Javier Bonet ◽  
Antonio J. Gil
Keyword(s):  
Kinetic Energy ◽  
Crack Propagation ◽  
Mathematical Models ◽  
Linear Elasticity ◽  
Strain Energy ◽  
Equations Of Motion ◽  
Two Dimensions ◽  
Discontinuous Solutions ◽  
Linear Elasticity Theory ◽  
Intersonic Crack Propagation

AbstractThis paper presents mathematical models of supersonic and intersonic crack propagation exhibiting Mach type of shock wave patterns that closely resemble the growing body of experimental and computational evidence reported in recent years. The models are developed in the form of weak discontinuous solutions of the equations of motion for isotropic linear elasticity in two dimensions. Instead of the classical second order elastodynamics equations in terms of the displacement field, equivalent first order equations in terms of the evolution of velocity and displacement gradient fields are used together with their associated jump conditions across solution discontinuities. The paper postulates supersonic and intersonic steady-state crack propagation solutions consisting of regions of constant deformation and velocity separated by pressure and shear shock waves converging at the crack tip and obtains the necessary requirements for their existence. It shows that such mathematical solutions exist for significant ranges of material properties both in plane stress and plane strain. Both mode I and mode II fracture configurations are considered. In line with the linear elasticity theory used, the solutions obtained satisfy exact energy conservation, which implies that strain energy in the unfractured material is converted in its entirety into kinetic energy as the crack propagates. This neglects dissipation phenomena both in the material and in the creation of the new crack surface. This leads to the conclusion that fast crack propagation beyond the classical limit of the Rayleigh wave speed is a phenomenon dominated by the transfer of strain energy into kinetic energy rather than by the transfer into surface energy, which is the basis of Griffiths theory.

Modeling Analysis and Experiment Research on Rotary Motor Buffer Overflow Valve

2014 ◽  
Vol 709 ◽  
pp. 68-73
Author(s):  
Yuan Shen Zhang ◽  
Xue Ping Xian ◽  
Jie Yin
Keyword(s):  
Service Life ◽  
Operating Performance ◽  
Computer Software ◽  
Buffer Overflow ◽  
Experiment Research ◽  
Maximum Displacement ◽  
Hydraulic Impact ◽  
Modeling Analysis ◽  
Pressure Impact ◽  
Rotary Motor

This paper studies a buffer overflow valve that is attached to a hydraulic rotary motor which could reduce high hydraulic impact when the hydraulic rotary motor starts, brakes or suddenly reverses. A rotary motor buffer overflow valve was modeled and simulated using a computer software, AMESim, and the relation of the buffer overflow valve to the hydraulic impact experienced by the motor was analyzed. The cushioning property of the buffer overflow valve of a rotary motor is verified by using an excavator. It is concluded that having a reasonable design of the buffer overflow valve’s maximum displacement for the buffer set and diameter size for the buffer damping hole, it can reduce the pressure impact experienced by the hydraulic rotary motor and improve its operating performance, which also improves the service life of the system or its hydraulic components.

Theory Analysis for Magnetic Fluid Inclination Sensor

2010 ◽  
Vol 168-170 ◽  
pp. 1295-1298
Author(s):  
Ming Li Sun ◽  
Hai Rong Cui ◽  
Bin Wang ◽  
Shuang Lu
Keyword(s):  
Magnetic Fluid ◽  
Linear Dependence ◽  
Output Voltage ◽  
Vertical Plane ◽  
Signal Frequency ◽  
Theory Analysis ◽  
Peak Voltage ◽  
Factors Affecting ◽  
Sensor Sensitivity ◽  
Inclination Angles

The paper presents an inclination transducer with magnetic fluid, being dedicated to measure little inclination angles in comparison with a horizontal or a vertical plane. The functioning principle is submitted. The results of theory analysis show that output voltage of sensor and inclination angles are linear dependence. The factors affecting the sensor sensitivity are inspected, which include the exciting signal frequency, the peak voltage and the susceptibility of magnetic fluid.

Modeling of three-dimensional beam nonlinear vibrations generalizing Hencky’s ideas

2022 ◽  
pp. 108128652110679
Author(s):  
Emilio Turco
Keyword(s):  
Kinetic Energy ◽  
Strain Energy ◽  
Nonlinear Vibrations ◽  
Three Dimensional ◽  
Integration Scheme ◽  
Beam Model ◽  
Model Formulation ◽  
Discrete Approach ◽  
Numerical Integration Scheme ◽  
Proposed Model

In this contribution, a novel nonlinear micropolar beam model suitable for metamaterials design in a dynamics framework is presented and discussed. The beam model is formulated following a completely discrete approach and it is fully defined by its Lagrangian, i.e., by the kinetic energy and by the potential of conservative forces. Differently from Hencky’s seminal work, which considers only flexibility to compute the buckling load for rectilinear and planar Euler–Bernoulli beams, the proposed model is fully three-dimensional and considers both the extensional and shear deformability contributions to the strain energy and translational and rotational kinetic energy terms. After having introduced the model formulation, some simulations obtained with a numerical integration scheme are presented to show the capabilities of the proposed beam model.

The Rockburst Experiment Usage of Similar Material and the Mechanism of the Energy Releasing

2011 ◽  
Vol 295-297 ◽  
pp. 378-382 ◽  
Author(s):  
Jie Li ◽  
Yue Hong Qian ◽  
Da Peng Li
Keyword(s):  
Kinetic Energy ◽  
Strain Energy ◽  
Peak Velocity ◽  
Hydrostatic Stress ◽  
Similar Material ◽  
Simulation Test ◽  
Underground Engineering ◽  
Recovery Strain ◽  
High Geostress ◽  
Unloading Time

As one of the geological disasters, rockburst is often generated in underground engineering under excavation unloading conditions in high geostress areas. Taking advantage of the simulation test especially for the rock mass under high hydrostatic stress, the dynamic failure rockburst style resulted from instantaneous unloading in one direction was studied, whose peak velocity and acting time are analyzed. The results indicate that the formula for calculating peak velocity and the kinetic energy is proper and the kinetic energy is little portion of the recovery strain energy, most of which is dissipation in different ways; the unloading time at different positions apart from the free surface is nearly the same and more larger than the unloading wave’s disturbance time.

scholarly journals Study on Evolutionary Characteristics of Toppling Deformation of Anti-Dip Bank Slope Based on Energy Field

2020 ◽  
Vol 12 (18) ◽  
pp. 7544
Author(s):  
Liangfu Xie ◽  
Qingyang Zhu ◽  
Yongjun Qin ◽  
Jianhu Wang ◽  
Jiangu Qian
Keyword(s):  
Numerical Model ◽  
Kinetic Energy ◽  
Fracture Surface ◽  
Shear Deformation ◽  
Strain Energy ◽  
Energy Field ◽  
Bank Slope ◽  
Shallow Layer ◽  
Friction Energy ◽  
Toppling Deformation

The evolution of toppling deformation of anti-dip slope is essentially a process of energy dissipation and transformation. Aiming to study the characteristics of energy evolution in different stages, the DEM (discrete element method) software PFC (Particle Flow Code) was utilized to establish a two-dimensional numerical model for a bank slope in Chongqing based on geological background data and field investigation. The DEM model was proven to be reliable not only because the deformation discrepancy between the numerical model and actual bank slope was not large but also because some obvious fractures in the actual bank slope can readily be found in the numerical model as well. In this article, content about displacement in the shallow layer was analyzed briefly. Special effort was made to analyze the energy field and divide the toppling deformation process into three stages. (1) Shear deformation stage: this is an energy accumulating stage in which the strain energy, friction energy, and kinetic energy are all small and the deformation is mainly shear deformation in the slope toe. (2) Stage of main toppling fracture surface hole-through: all three kinds of energy present the increasing trend. The shear deformation in the slope toe expands further, and the toppling deformation also appears in the middle and rear parts of the bank slope. (3) Stage of secondary toppling and fracture surface development: strain energy and friction energy increase steadily but kinetic energy remains constant. Deformation consists mainly of secondary shearing and a fracture surface in the shallow layer. Secondary toppling and fracture surface develop densely.

scholarly journals On Dynamic Extension of a Local Material Symmetry Group for Micropolar Media

Symmetry ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1632
Author(s):  
Victor A. Eremeyev ◽  
Violetta Konopińska-Zmysłowska
Keyword(s):  
Energy Density ◽  
Kinetic Energy ◽  
Symmetry Group ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Constitutive Relations ◽  
Kinetic Energy Density ◽  
Material Symmetry ◽  
Local Material ◽  
Micropolar Media

For micropolar media we present a new definition of the local material symmetry group considering invariant properties of the both kinetic energy and strain energy density under changes of a reference placement. Unlike simple (Cauchy) materials, micropolar media can be characterized through two kinematically independent fields, that are translation vector and orthogonal microrotation tensor. In other words, in micropolar continua we have six degrees of freedom (DOF) that are three DOFs for translations and three DOFs for rotations. So the corresponding kinetic energy density nontrivially depends on linear and angular velocity. Here we define the local material symmetry group as a set of ordered triples of tensors which keep both kinetic energy density and strain energy density unchanged during the related change of a reference placement. The triples were obtained using transformation rules of strain measures and microinertia tensors under replacement of a reference placement. From the physical point of view, the local material symmetry group consists of such density-preserving transformations of a reference placement, that cannot be experimentally detected. So the constitutive relations become invariant under such transformations. Knowing a priori a material’s symmetry, one can establish a simplified form of constitutive relations. In particular, the number of independent arguments in constitutive relations could be significantly reduced.

scholarly journals Experimental Study of Influence of Support Failures on Rockbursts under True-Triaxial Condition

2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Guoshao Su ◽  
Tianbin Li ◽  
Jianqing Jiang ◽  
Guoqing Chen ◽  
Jinghai Mo
Keyword(s):  
Kinetic Energy ◽  
Elastic Strain ◽  
Strain Energy ◽  
Elastic Strain Energy ◽  
Test System ◽  
Surrounding Rock ◽  
Underground Engineering ◽  
True Triaxial ◽  
Static Failure ◽  
Rock Specimens

Supports can effectively reinforce the surrounding rock after excavation in underground engineering. However, a support failure may cause an extremely intense rockburst. Hence, the influences of support failures, including support forces, support failure timings, and support failure rates, on rockbursts were systematically investigated in the present study. Unloading tests on rock specimens, using a true-triaxial rockburst test system, were performed to simulate rockbursts induced by support failure. The experimental results indicate that increasing support forces increased the prepeak accumulated elastic strain energy, the kinetic energy of the ejection fragment, and the ratio between the kinetic energy and release strain energy, whereas the damage to the rock specimens declined. During the testing process, the longer it took to unload the minimum stresses was, which means that the later the support failed, the greater the prepeak accumulated elastic strain energy was, the kinetic energies of the ejection fragments were, and the ratio of the kinetic energy and release strain energy was. Furthermore, as the support failure rate incremented, the kinetic energies of the ejection fragments of the rockbursts linearly increased, the failure mode of the rock changed from static failure to dynamic rockbursts, and the intensities of the rockbursts increased.

scholarly journals On Torque and Tumbling in Swimming Escherichia coli

2006 ◽  
Vol 189 (5) ◽  
pp. 1756-1764 ◽  
Author(s):  
Nicholas C. Darnton ◽  
Linda Turner ◽  
Svetlana Rojevsky ◽  
Howard C. Berg
Keyword(s):  
Escherichia Coli ◽  
High Speed ◽  
Polymorphic Transformations ◽  
Charge Coupled Device ◽  
Motor Torque ◽  
Rotation Rates ◽  
Applied Torque ◽  
Resistive Force Theory ◽  
Rotary Motor ◽  
Single Flagellum

ABSTRACT Bacteria swim by rotating long thin helical filaments, each driven at its base by a reversible rotary motor. When the motors of peritrichous cells turn counterclockwise (CCW), their filaments form bundles that drive the cells forward. We imaged fluorescently labeled cells of Escherichia coli with a high-speed charge-coupled-device camera (500 frames/s) and measured swimming speeds, rotation rates of cell bodies, and rotation rates of flagellar bundles. Using cells stuck to glass, we studied individual filaments, stopping their rotation by exposing the cells to high-intensity light. From these measurements we calculated approximate values for bundle torque and thrust and body torque and drag, and we estimated the filament stiffness. For both immobilized and swimming cells, the motor torque, as estimated using resistive force theory, was significantly lower than the motor torque reported previously. Also, a bundle of several flagella produced little more torque than a single flagellum produced. Motors driving individual filaments frequently changed directions of rotation. Usually, but not always, this led to a change in the handedness of the filament, which went through a sequence of polymorphic transformations, from normal to semicoiled to curly 1 and then, when the motor again spun CCW, back to normal. Motor reversals were necessary, although not always sufficient, to cause changes in filament chirality. Polymorphic transformations among helices having the same handedness occurred without changes in the sign of the applied torque.

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