scholarly journals Controllable biomimetic birdsong

2017 ◽  
Vol 14 (133) ◽  
pp. 20170002 ◽  
Author(s):  
Aryesh Mukherjee ◽  
Shreyas Mandre ◽  
L. Mahadevan
Keyword(s):  
Static Load ◽  
Dynamic Loads ◽  
Linear Actuator ◽  
Quiescent State ◽  
Rubber Tube ◽  
Static Tension ◽  
Wave State ◽  
Dynamic Variations ◽  
Periodic State ◽  
Neuromotor System

Birdsong is the product of the controlled generation of sound embodied in a neuromotor system. From a biophysical perspective, a natural question is that of the difficulty of producing birdsong. To address this, we built a biomimetic syrinx consisting of a stretched simple rubber tube through which air is blown, subject to localized mechanical squeezing with a linear actuator. A large static tension on the tube and small dynamic variations in the localized squeezing allow us to control transitions between three states: a quiescent state, a periodic state and a solitary wave state. The static load brings the system close to threshold for spontaneous oscillations, while small dynamic loads allow for rapid transitions between the states. We use this to mimic a variety of birdsongs via the slow–fast modulated nonlinear dynamics of the physical substrate, the syrinx, regulated by a simple controller. Finally, a minimal mathematical model of the system inspired by our observations allows us to address the problem of song mimicry in an excitable oscillator for tonal songs.

The Specific Characteristics of Shock and Blast Impacts on Construction Sites

2021 ◽  
pp. 81-88
Author(s):  
A.A. Komarov ◽  
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Dynamic Loads ◽  
Potential Hazard ◽  
Construction Sites ◽  
Static Loads ◽  
Equivalent Static Loads ◽  
Plane Crash ◽  
Nuclear Plants ◽  
The Impact

The practices of hazardous and unique facilities’ construction imply that specific attention is paid to the issues of safety. Threats associated with crash impacts caused by moving cars or planes are considered. To ensure safety of these construction sites it is required to know the potential dynamic loads and their destructive capacity. This article considers the methodology of reducing dynamic loads associated with impacts caused by moving collapsing solids and blast loads to equivalent static loads. It is demonstrated that practically used methods of reduction of dynamic loads to static loads are based in schematization only of the positive phase of a dynamic load in a triangle forms are not always correct and true. The historical roots of this approach which is not correct nowadays are shown; such approach considered a detonation explosion as a source of dynamic load, including TNT and even a nuclear weapon. Application of the existing practices of reduction of dynamic load to static load for accidental explosions in the atmosphere that occur in deflagration mode with a significant vacuumization phase may cause crucial distortion of predicted loads for the construction sites. This circumstance may become a matter of specific importance at calculations of potential hazard of impacts and explosions in unique units — for instance, in the nuclear plants. The article considers a situation with a plane crash, the building structure load parameters generated at the impact caused by a plane impact and the following deflagration explosion of fuel vapors are determined.

scholarly journals Effect of Vibrating Footing on a Nearby Static – Load Footing

2019 ◽  
Vol 5 (8) ◽  
pp. 1738-1752 ◽  
Author(s):  
Saif Khalil Ibrahim ◽  
Waad A. Zakaria
Keyword(s):  
Dynamic Response ◽  
Static Load ◽  
Dynamic Loads ◽  
Experimental Program ◽  
Vibration Source ◽  
Mechanical Oscillator ◽  
Collapsible Soil ◽  
Dynamic Motion ◽  
Steel Container ◽  
Mass Type

This paper presents an experimental study on the dynamic response of square footings under effect of dynamic load comes from adjacent footing called the (source of vibration (which is excited by a known vibration source placed on the top of it, the objective is to study the effect of dynamic motion of the source of vibration on a nearby footing, called second footing, both footings rest on collapsible soil (gypseouse soil) with gypseouse content (60%). The study is performed through wide experimental program in dry and soaked condition. The first footing (source vibration) and the second footing have dimensions (80 80 40), (100 100 40) mm respectively and are manufactured from steel, then the two footings placed centrally over soil after prepared it in layers’ form in steel container with (1000 500 500) mm. The first footing exposed to vertical harmonic loading by using a rotating mass type mechanical oscillator to gives a similar effect of the dynamic loads, the second footing loaded with static weight only, under the dynamic excitation. The tests are conducted under dynamic response for three frequencies (10, 20, 30) Hz, the movement (displacement amplitude, velocity, and acceleration) of the second footing studied by varying spacing between the footings. The results showed that the amplitude of displacement, velocity, and acceleration for the second footing decreases when the spacing between footing increase. In addition, the value of these parameters at dry state is greater than its value at soaked state.

scholarly journals Behavior of normal strength concrete slabs under static and dynamic loads

2021 ◽  
Author(s):  
Turky Sami Jeddawi
Keyword(s):  
Impact Loading ◽  
Static Load ◽  
Dynamic Loads ◽  
Concrete Slabs ◽  
Normal Strength Concrete ◽  
Deformation And Failure ◽  
Absorption Energy ◽  
Static And Dynamic Loads ◽  
Normal Strength ◽  
The Impact

An experimental investigation has been conducted to determine the deformation and failure characteristic of slab under static and dynamic loads. Two identical reinforced concrete (RC) of dimensions 1950 x 1950 x 100 mm are tested under same boundary conditions. All top and bottom reinforcement are 10 M doubly plates reinforcement with total 1.0 % steel ratio. The static load is applied at the midpoint of the slab by using load cell 400 x 400 mm with a capacity of 250 kN. The static load increment used in this investigation is 5 kN. The dynamic load is applied at the midpoint of the slab by using a drop-weight of 475 kg from a height of 4.15 m generating an impact energy of 19.24 kJ with impact velocity of 9 m/s. The experimental results revealed that the absorption energy of the impact loading is about 1.4 times the static loading. The maximum deflection is found to be slightly higher for impact loading.

scholarly journals Numerical Study on the Elastic Deformation and the Stress Field of Brittle Rocks under Harmonic Dynamic Load

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 851
Author(s):  
Siqi Li ◽  
Shenglei Tian ◽  
Wei Li ◽  
Xin Ling ◽  
Marcin Kapitaniak ◽  
...  
Keyword(s):  
Stress Field ◽  
Numerical Simulations ◽  
Elastic Deformation ◽  
Fatigue Damage ◽  
Dynamic Load ◽  
Static Load ◽  
Numerical Study ◽  
Rock Fracture ◽  
Dynamic Loads ◽  
Brittle Rocks

In order to study the deformation displacement and the stress field of brittle rocks under harmonic dynamic loading, a series of systematic numerical simulations are conducted in this paper. A 3D uniaxial compression simulation is carried out to calibrate and determine the property parameters of sandstone and a model of the cylindrical indenter intruding the rock is proposed to analyze the process of elastic deformation. Four main parameters are taken into account, namely the position on the rock, the frequency and the amplitude of dynamic load, the type of indenter and the loading conditions (static and static-dynamic). Based on the analysis undertaken, it can be concluded that both of the deformation displacement and stress field of the rock change in a harmonic manner under the static-dynamic loads. The frequency and the amplitude of harmonic dynamic load determine the period and the magnitude of the rock response, respectively. In addition, the existence of harmonic dynamic load can aggravate the fatigue damage of the rock and allow a reduction in static load. Our investigations confirm that the static-dynamic loads are more conducive to rock fracture than static load.

Effects of Impact on the Behavior of a Flexible Multiple Disk Clutch and Brake

1987 ◽  
Vol 109 (4) ◽  
pp. 416-421 ◽  
Author(s):  
Kosuke Nagaya
Keyword(s):  
Dynamic Response ◽  
Laplace Transform ◽  
Dynamic Behavior ◽  
Circular Plate ◽  
Static Load ◽  
Equation Of Motion ◽  
Dynamic Loads ◽  
The Laplace Transform ◽  
The Impact

This paper discusses the dynamic behavior of a flexible multiple disk clutch subjected to dynamic loads. The expressions for obtaining the dynamic response and the transmission torque of the clutch have been derived from the equation of motion of a circular plate by applying the Laplace transform procedure. The results for the clutch subjected to a static load have also been obtained. The comparison between both static and dynamic results has been made to clarify the effect of the impact of the load on the behavior of the clutch.

Resilient Railpads: Their Dynamic Behaviour in the Laboratory and on Track

1989 ◽  
Vol 203 (1) ◽  
pp. 25-32 ◽  
Author(s):  
S L Grassie
Keyword(s):  
Impact Test ◽  
Dynamic Behaviour ◽  
Static Load ◽  
Dynamic Stiffness ◽  
Dynamic Loads ◽  
Dynamic Strain ◽  
Deflection Curve ◽  
Surface Profiling ◽  
Effective Dynamic ◽  
Load Deflection Curve

Resilient railpads in a variety of materials and with different surface profiling have been tested in the laboratory and in track. A laboratory impact test based on that initially developed at the Battelle Columbus Laboratories provides a reliable ranking of the extent to which railpads attenuate dynamic strain in concrete sleepers in track. The test is also a good indication of the average attenuation provided by a pad in track. If dynamic loads in track are particularly severe the fractional attenuation provided by a pad is greater than that indicated by the laboratory impact test. Laboratory resonance apparatus, in which the pad is the principal resilient element in a simple dynamic system, has been made to find the railpad's effective dynamic stiffness. There is good correlation between the stiffness measured in track and that measured in this apparatus. A pad's dynamic stiffness is consistently at least as great as its tangent stiffness found from the static load/deflection curve. The load/deflection behaviour of a pad in track can be found from measurements in an assembly of rail and sleeper in the laboratory.

Modification of a Heavy Vehicle Suspension to Reduce Road Damage

1995 ◽  
Vol 209 (3) ◽  
pp. 183-194 ◽  
Author(s):  
D J Cole ◽  
D Cebon
Keyword(s):  
Static Load ◽  
Dynamic Loads ◽  
Vehicle Suspension ◽  
Leaf Spring ◽  
Test Rig ◽  
Test Vehicle ◽  
Vehicle Simulation ◽  
Spring Suspension ◽  
Articulated Vehicle ◽  
Static Performance

A test rig for measuring the quasi-static performance of tandem suspensions in the laboratory is described. Measurements on a standard tandem leaf-spring suspension show it to have high effective stiffness in bounce and poor static load equalization. A method for eliminating the spring-end friction is investigated, and found to improve the performance significantly. A two-dimensional articulated vehicle simulation is validated with measurements from a test vehicle. The simulation is then used to study the effect on dynamic tyre forces of three modifications to the trailer suspension: softer springs; elimination of spring-end friction; and hydraulic dampers. The r.m.s. dynamic loads generated by the trailer axles are predicted to decrease by approximately 31 per cent and the theoretical road damage is predicted to decrease by about 13 per cent. The trailer suspension of the test vehicle is adapted to incorporate the three modifications and the measured reductions in dynamic tyre forces are found to be about half those predicted by the simulation.

scholarly journals Numerical Analysis of Roadway Rock-Burst Hazard Under Superposed Dynamic and Static Loads

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3761 ◽  
Author(s):  
Kong ◽  
Jiang ◽  
Jiang ◽  
Wu ◽  
Chen ◽  
...  
Keyword(s):  
Energy Density ◽  
Rock Burst ◽  
Elastic Energy ◽  
Dynamic Load ◽  
Static Loading ◽  
Static Load ◽  
Dynamic Loads ◽  
Loading Conditions ◽  
Static Loads ◽  
Elastic Energy Density

Microseismic events commonly occur during the excavation of long wall panels and often cause rock-burst accidents when the roadway is influenced by dynamic loads. In this paper, the Fast Lagrangian Analysis of Continua in 3-Dimensions (FLAC3D) software is used to study the deformation and rock-burst potential of roadways under different dynamic and static loads. The results show that the larger the dynamic load is, the greater the increase in the deformation of the roadway under the same static loading conditions. A roadway under a high static load is more susceptible to deformation and instability when affected by dynamic loads. Under different static loading conditions, the dynamic responses of the roadway abutment stress distribution are different. When the roadway is shallow buried and the dynamic load is small, the stress and elastic energy density of the coal body in the area of the peak abutment stress after the dynamic load are greater than the static calculations. The dynamic load provides energy storage for the coal body in the area of the peak abutment stress. When the roadway is deep, a small dynamic load can still cause the stress in the coal body and the elastic energy density to decrease in the area of the peak abutment stress, and a rock-burst is more likely to occur in a deep mine roadway with a combination of a high static load and a weak dynamic load. When the dynamic load is large, the peak abutment stress decreases greatly after the dynamic loading, and under the same dynamic loading conditions, the greater the depth the roadway is, the greater the elastic energy released by the dynamic load. Control measures are discussed for different dynamic and static load sources of rock-burst accidents. The results provide a reference for the control of rock-burst disasters under dynamic loads.

Behaviour in Track of Concrete Sleepers with Resilient Railpads

1989 ◽  
Vol 203 (2) ◽  
pp. 97-101 ◽  
Author(s):  
S L Grassie
Keyword(s):  
Dynamic Loading ◽  
Short Wavelength ◽  
Field Experiments ◽  
Static Load ◽  
Dynamic Loads ◽  
Track Geometry ◽  
Using Data

Loading under traffic of concrete sleepers with a variety of resilient railpads is examined using data from several field experiments. In all cases dynamic loads on sleepers were significantly reduced using the pads. Quasi-static load reduces the ability of railpads to attenuate dynamic loads by a small but consistent amount. Dynamic loads are appreciably greater with poorly packed ballast. Short wavelength irregularities which most significantly affect dynamic loading of track are not detected by conventional track geometry cars.

Stiffness of Magnetic Bearings Subjected to Combined Static and Dynamic Loads

1992 ◽  
Vol 114 (4) ◽  
pp. 785-789 ◽  
Author(s):  
D. K. Rao ◽  
G. V. Brown ◽  
P. Lewis ◽  
J. Hurley
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Dynamic Stiffness ◽  
Load Ratio ◽  
Magnetic Bearing ◽  
Dynamic Loads ◽  
Approximate Design ◽  
Critical Gap ◽  
Gap Fraction ◽  
Static And Dynamic Loads

This paper investigates the stiffness of a magnetic bearing that is subjected to the combined action of static and dynamic loads. Since their sum cannot exceed the saturation load, a large static load will imply that the bearing can carry only a small dynamic load. This smaller dynamic load together with the practical vibration amplitude define a practical upper bound to the dynamic stiffness. This paper also presents approximate design formulas and curves for this stiffness capacity as a function of the ratio of dynamic and static loads. In addition, it indicates that vibrations larger than a certain gap fraction can destabilize the magnetic bearing. This gap fraction, called the critical gap fraction, depends on the dynamic and static load ratio. For example, if the dynamic load is half of the static load, the use of more than 25 percent of gap can destabilize the bearing.

Sign in / Sign up

Export Citation Format

Share Document