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# Electromechanics - Science topic

Explore the latest questions and answers in Electromechanics, and find Electromechanics experts.

Questions related to Electromechanics

Hello All, I simulated a resonator in comsol and I use electromechanical physics. I need displacement in result and I want cir physics at the same time to add resistance. Is it possible?

I mean, in articles, everyone refers to the piezoelectric charge constant d

_{31}or the electromechanical coupling factor k_{33}or the piezoelectric voltage constant g_{15}and so on, as if it is the most natural notation in piezoelectricity to state the constants in function of the axes, as described here:In my view, it is not such a trivial notation that one can understand naturally without studying it. However, very rarely is any explanation given about this notation and the vast majority of articles begin to present piezoelectric constants without the slightest clarification of what they refer to. Even review articles! I already saw the notation of d

_{11}and d_{33}in an article from 1934, therefore not recent at all:But I cannot find a reference source where the convention of this notation is defined.

In short, I want to write "the coefficient d

_{33}according to the notation by [citation X]." Is there any convention or standard that we can refer to?Is there anyone using an electrochemical working station CHI660E for characterisation of electromechanical performance of piezoresistive pressure sensor?

Could you suggest source, references or web sites about the using process?

I am working on an electro-mechanical system for which PID tuner gives best step regulation with settling time of about 80s. But as it is commonly observed, ILC leads to step regulation with negligible settling time after several iterations, Is is possible for delayed system too? If yes, what should be approach (P, PD, PID or anything else) in ILC update function? Please share your experience and some literature!

Thanks

Basically, I am doing M.tech project on damage detection using piezoelectric sensor by obtaining change in Electromechanical Impedance (EMI) plot for this I want plot between conductance/susceptance vs frequency.Can anyone Suggest how to do this .I am getting some result in my analysis which I have attached below which I have obtained through modal analysis but i feel this is right way to do it.Please anyone guide me

i am designing RF MEMS Switch, for that i need to solve two physics i.e. electromechanics and electromagnetics. And i need to use the results of the electromechanics to solve electromagnetic physics. i doing the entire project in COMSOL tool.

now my questions are:

1. In electromechanics::: I kept the gap between the cantilever the the base is 0.8um, but when i apply the actuation voltage i am getting the displacement more than o.8um, here base material is silicon dioxide in solid state. [shown in figure 1]

2. In electromagnetics::: the rf input signal is not propagating to output through displaced cantilever , here i tried to match the impedance but theree is no use. [Shown in Figure 2]

3. how to use the results of one physics as the initial values of other physics. [shown in figure 3]

To study the Dual Fed Induction Generator principle in closed loop arrangement, I want the least possible motor generator set, example I want 0.25 HP or less than that system. Any specific make is available, please suggest.

Thanks In Advance.

The specifications are in term of R, L, B, J, kv, kt

The max output force of electromechanical braking system is 3500N

Which method has the highest sensitivity for SHM evaluation using piezoelectrics: ultrasound or electromechanical impedance?

I want to find data about oil viscosity, water in oil, metallic wear debris particles for condition monitoring for electromechanical systems. The data should be monitored by online sensors because the sampling period of offline analysis is large. Let me know if you have any suggestion.

I did the simulation using electromechanics module in comsol but, ended up getting solution which shows variation (not a smooth curve) with parametric sweep (changing the dimensions of the plate with small iteration). I am a beginner in comsol and any help in this domain will be helpful !

is there any other software which could solve this problem ?

I have mostly seen composites made of piezoelectric ceramics layered with magnetostrictive alloys for the demonstration of the magneto-electric effect.

My understanding is that piezoceramics are typically softer (easier to deformation) and have a higher electromechanical coupling than piezoelectric single crystal materials like quartz and LiNbO3.

So they seem like a more obvious choice for magneto-electric devices.

But are there examples of magnetoelectric devices using a single crystal material layered with a magnetostrictive material? And would there be any benefits to this arrangement?

I am curious if any particular device structures might be beneficial, instead of just layering the materials.

I'm actually investigating the RFD proprieties in aging and so I need to describe alsothe electromechanical delay (EMD). Interestingly, with my current acquisition apparatus, the delay is really short (<40ms) while when I analyse the data from a different one (same software and hardware brand) the delay is consistenly higher (around 100-150 ms).

Excluding the EMG wave summation's effect and the variability within/between subjects, can it depends from the apparatus itself? Does someone have the same problem?

And more generally, could the EMD be so dipendent from the apparatus to invalidate every usefulness of absolute data?

I prepared PVDF-ceramic composite thick film (dimension is 1cm x 1cm x 0.45 mm)and I want to know, how can I determine the electromechanical coupling factor of this sample. what is the formula used for this and what is the experimental/measurement technique to determine the electromechanical coupling factor.

Kindly help me to resolve this problem.

The sample machine has been fabricated with 110N-m ....

I need to open a poppet valve which face a pressure up to 20 bar. The result is that there will be 7000 newton and I need a very fast opening (few milliseconds) for a 7.5 mm stroke.

The only actuator which go closer is this pneumatic one(http://www.smcpneumatics.com/pdfs/smc/70AMGP.pdf) but it could reach 400 mm/s. For my purpose I would need something around 3000 mm/s.

So, is there anybody who knows some different types of actuator, even electrical, piezo etc. with this features

-7000 N

-up to 3000 mm/s speed

-7.5 mm stroke

Thank you

i want to use the servomotors but i don't know that hoe much torque is required, so i can buy the appropriate motor..

We are working of six small hydropower projects each plant has two francis machines with capacity of 3.5 MW to 15MW and head 32m to 65m. What could be the reasonable E&M cost for those plants.

Several papers tend to bring in generator torque, and also electrical torque, which I think is the same thing as electromechanical torque. The issue is that all these terminologies get mixed up so I tend to be confused . Apart from the wind torque, every other torque in the WT system is confusing right now. So please help with an explanation and diagrams if possible. Thank you very much

Hi all

I would like to know, what is the dynamic range of gyroscope and how the dynamic range of a MEMS gyroscope is estimated during mechanical structure design.

Thank you

Jayaprakash Reddy

I know generally it contains a maze of channels and passages that direct hydraulic fluid to the numerous valves which then activate the appropriate clutch pack or band servo to smoothly shift to the appropriate gear for each driving situation. How exactly the process occur?

Hi,

I think that you have done excellent work in validating that the magnetic micropropellers can be used for medical purposes. In your IEEE 2017 article (Rubbing Against Blood Clots using Helical Robots: Modeling and In Vitro Experimental Validation) you reported a linear approach velocity and magnetic frequency relation while the removal rate started to drop beyond 35 Hz. Could it be that the decrease in the removal rate is due to a decrease in the step-out frequency of the propeller because of "wall effects", which is the blood clot in this case? My other question is, will multiple propellers simultaneously rubbing the blood clot improve the removal rate?

Thank you,

Michiko

The Best COMSOL module for Piezo electric Polymeric Substrtates which uses SAW, FPW etc., Acoustic modes. Kindly suggest the best out of 3 with explanation??

a) Structural Mechanics

b) Acoustic

c) MEMS modules

Dear colleges,

I am working on a parallel robot where the actuated joints are in one leg, i.e. q1 and q2 in the figure.

Then, I have problems with inverse geometry model (IGM) and kinematic model.

In terms of the IGM, I obtain the equations by suppressing the passive angles:

from the left leg: (x-q1)^2+(y-q2)^2=l^2

from the right leg: (x-d)^2+y^2 = l^2.

However, it seems to be impossible to solve q1 and q2. Is there another way to get IGM for this model?

Also, I differentiate the geometry model and get the kinematic model, which has a similar problem.

A[dx; dy]+B[dq1;dq2] = 0

But the B is a matrix [2(q1-x), 2(q2-y); 0 , 0];

I guess the main difficulty is because all the actuated joints are in the same leg.

Will it be a sine wave of very low amplitude....which is not effected by the change in resistance of a particular arm??

What piezoelectric coefficient is considered in stretching mode and how can we calculate it. Is there any specific equipment for this like d33 meter.

Regards,

I'm designing a log periodic toothed planner antenna for frequency range (400 MHz-5800 MHz). Anyone can help me out how can I calculate the exact no. of teeth that give resonance on specific frequencies.

We are performing micro machining with Electro Chemical Machining (ECM) process. We look forward for a mechanism to maintain constant gap between electrodes during machining

I want to measure the phase lag (time lag) between LDV vibrometer and other equipment such as voltage and current probes with accuracy of 1 degree (~nanoseconds). Unfortunately, the vibrometer has a "response delay" in micro second order, comparing to ns order "response delay" in current and voltage probes. For measuring with nanosecond accuracy I should get rid of sensors response delays.

I am using a Polytech OFV-3001 LVD using velocity decoder (based on doppler effect) for measuring displacement/velocity around 20kHz-50kHz frequencies.

If I apply a DC voltage on peltier element, will the source voltages changes or not?

Over the past few years, a number of handheld devices that report nanoparticle concentrations have become commercially available. Several of these devices rely on an electrometer detector, which measures the charge of deposited particles (incl. the Testo DiSCmini, Naneos Partector, and Aerasense NanoTracer). Several studies on the accuracy of these devices have been published by leading research groups e.g. BAUA, IDAEA-CSIC, IGF, IUTA, INRS, U of Iowa and TUT. These studies report that the measurement accuracy is mostly within ±30% for a particle size range from 20 nm to 300/400 nm. I would be interested in learning how vibrations and mechanical shocks impact that measurement accuracy during mobile aerosol measurements, e.g. in a moving vehicle.

I want to make a set up for micro-edm machine in which workpiece will vibrate with the help of PZT actuator. I want to understand how power amplifier connected with it? And also, how can i create different frequency and amplitude of vibration. I have heard function generator does this, but how?

Hi,

I am trying to find variation in capacitance between two plates with applied body load. I defined an air box around the plates. Now I'm trying with electromechanics physics for applying body load and finding capacitance. I defined the two plates as linear elastic material. Applied body load to the moving plate. I applied 1V to moving plate and fixed plate is grounded. I also gave parametric sweep for body load. But capacitance is not varying with body load.

What changes should I make to get a varying capacitance? Please Help.

Thank You,

Aswathi M Madhu

Why biaxial stretched dielectric elastomers have higher electromechanical actuation in comparison to uniaxially stretched samples even if we take same thickness strain?

Attempting to measure slew rates (of a large electromechanical assembly) as low as 0.1mrad/sec

While measuring D33 coefficient on piezoelectric ceramic pellets, that have been polled in DC electric field and silver electrode platted by D33 meter, a positive D33 coefficient is observed every time, no change of sign of coefficient occurs upon changing side of pellets. So my question is, should the sign of d33 coefficient be changed when reversing pellet or it is always positive? If not, then what might be reasons for this?

To make coding for arduino mega, we need to know the suitable angle to make the leg of a quadruped robot can move smoothly and from calculation we can enter the angle at coding to move the robot. Because when we know the equation, it will be easier to compare with trial and error to find the best angle that servo motor turn to move the legs.

While using EDM for different inputs Roughness is varying . What is the min roughness and range that can be attained by EDM Cutting

Is there any other method to measure piezoelectric coefficient besides using Piezo response force microscopy ( PFM) for thin film piezoelectric MEMS such as AIN?

I have a smart bean coupled with two piezoelectric patches and I want to control it using Simulink. In order to do so, the modal matrices that have the eletromechanical properties, are necessary.

Identification of the servo electromechanical actuator, held directly on the real loaded actuator experimentally is the most effective way for determining its structure and parameters. Thus obtained mathematical model can be used for both velocity/position closed loop design and verification of analytical modeling.

I I want to discuss this issue for preparing common research paper further.

hi

Are Mechanical and Electromechanical Time constants in any sense different and related to electric time constant?

Thanks

Hi, i want to simulate the thermal stress effect (e.g. temperature and heat flux) on prestressed eigen frequency analysis of a MEMS model which has built in "Electromechanics" and has input voltage, but i haven't seen any changes in results in natural frequencies, like COMSOL ignoring the thermal stress physics for eigen frequency analysis. can anyone help?

Thanks in advance

Hi all

I have read an example in the electric machinery book by Professor Bimbhara in the chapter related to electromechanical energy conversion. There, he calculates the force exerted to the rotor due to an increase of airgap by x in one side and a decrease by x in the other side. His calculations show that if the airgap is not unifirm, then there will be a radial force on the rotor, in the direction with the lesser gap length. My question is regard his calculations. As we know, the force can be calculated using: F=B^2/(2mu0)*surface area that the flux passes. It seems to me that using this equation, there are still equal forces on the rotor if the airgap length on one side increases by x and decreases by x in the other side. This is because the airgap flux density (B in the equation) is equal on both sides.

How could you justify that book's derivation?

Please find attached the file.

Can anyone help about using the PID controller based in PLC devices to control reactor temp.? Thank you

What type of actuator(s) is/are suitable for simultaneous axial and torsional fatigue loading on a cantilever round bar with frequency of 5 Hz in load control range of 0-8000 N and 0-25 N.m respectively? I have found Direct Drive actuators both for linear and rotary. I have also choices of linear servomotors and piezo actuators as linear actuators. Concerns are:

- No backlash.
- achieving the loads with no motion as it is a cantilever beam
- 1 million cycle of loading (regular maintenance can be considered during the test)

Thank you for your assist.

I am studying the mechanical properties of the inhibitory jaw reflex evoked by the electrical stimulation of the upper lip in man (I record bite force by using an isometric force transducer between the anterior teeth, and I record bilateral EMG from both masseter muscles). In the course of my study, I found that the reflex relaxation had a slower onset and lasted longer than the corresponding period of suppression of electromyographic (EMG) activity. While the latter finding is exactly as one would expect, the former is, arguably, more surprising.

The mean latencies of onset of this response were: biting force, 52.7ms (SD:9.5ms); right masseter EMG, 37.9ms (SD:4.3ms); left masseter EMG, 38.5ms (SD:4.7ms). The latency of the bite force response was significantly longer than those for either EMG (Repeated Measures ANOVA with Bonferroni corrected paired t tests: P<0.0001). The onset of the force reduction was delayed comparing to the EMG inhibition by about 14.5ms. This was not due to any inertia in the force transducer.

When trying to find an explanation for this delay, I came across the Poggesi et al. paper (see below). Do you think this delay could be explained by the feedback mechanism between attached cross-bridges and thin filament activation? Or this mechanism couldn't last for 14ms and therefore it might be something else? Could it be due to more than one factor?

I am interested in any Ideas in improving the classical solutions known for bimetal actuators .

Mihail AIGNATOAIE

Tech. Uni. Iasi, Romania

I am trying to model a position control problem with simulink simscape components. The following components are used. 1. PI(s),H Bridge , controlled PWM , a comparator to generate a direction for H bridge, DC motor, Gear box, and spring representing gear box stiffness and a load as inertia ,inertia of the order of 10e6 kg*m^2, and suitable PS-S and S-PS blocks and a ideal rotational reference sensor.

2. When i try to simulate the system the system works and tracks the input with few SS error and with small oscillation. Now i am required to tune the system using PID tunning.

As i understood prior to tuning of the plant I am required to linearize the plant and the only i can apply automated PID Tuning.

I tried the linearization of the plant with system identification using simulutated I/O in the PID tunning tool box. During this i observed the instead of tracking step command the output continuously increase like a ramp. Can any one help to solve the issue ?

Also I attached two plots one with simulation result with P=1 and I=1 and running simulation for 40 sec( tried upto 200 sec) , the observation is that output is trying to track the input value of 0.01 degree , but during the system identification the output looks like a ramp and not settling , the figure pid.png show system identification GUI. Any clue for solving the issue?

Please Help!

Thanks & regards

Prima.R