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# Mechanical Engineering - Science topic

Explore the latest questions and answers in Mechanical Engineering, and find Mechanical Engineering experts.

Questions related to Mechanical Engineering

Hi All,

I am trying to generate the 3D corneal surface from the Zernike Polynomials. I am using the following steps, can anyone please let me know whether they are accurate

Step 1: Converted the cartesian data (x, y, z) to polar data (rho, theta, z)

Step 2: Nomalised the rho values, so that they will be less than one

Step 3: Based on the order, calculated the Zernike polynomials (Zpoly), (for example: if the order is 6, the number of polynomials is 28 )

Step 4: Zfit = C1 * Z1 + C2 * Z2 + C3 * Z3 + ......... + C28 * Z28

Step 5: Using regression analysis, calculated the coefficient (C) values

Step 6: Calculated the error between the predicted value (Zfit) and the actual elevation value (Z)

Step 7: Finally, converted the polar data (rho, theta, Zfit) to Cartesian coordinates to get the approximated corneal surface

Thanks & Regards,

Nithin

For a regular Low Temperature Striling Engine, how much mechanical energy can I produce by using hot water at around 350K?

I want to calculate

**Rayleigh number**and**Nusselt number**of a**PCM-heatsink**to analyze the intensity of the**natural convection of PCM**. There are some**fins**inside my heatsink to enhance the heat transfer. Now I am having trouble calculating the**characteristic length**to use in Rayleigh and Nusselt dimensionless numbers.I would be grateful if you could help me.

I am encountering difficulties in employing Acusolve to simulate a basic landscape, whether it be from a raised or grounded source, which is proving to be a setback. In Acusolve, I am need to know how to include characteristics of H2S in the materials library. What is the suitable physics model in Acusolve for simulating H2S dispersion?

Hello,

I am a Master's student of Mechanical Engineering at Gwangju Institute of Science and Technology, South Korea. What can be a good thesis topic for mechanical students on AFM research?

I am working on AFM for the last six months. I have gained sufficient knowledge about the components of AFM, and their effect on the speed of AFM.

For my thesis, I want to work on the side of Signal Processing (to improve the resolution of the acquired images), I am more familiar with the control work and if the control doesn't take a long time I will be happy to work on the control side.

I have searched a lot about research trends on AFM and get to know we have two trends

1. High-Speed AFM

2. High-Resolution AFM

For High Resolution I didn't find any publication and ideas, almost every author say they use FFT and Gwyddion software for making images better. Please suggest me some topics for my MS thesis. I have AFM Device and my lab has almost all the necessary tools and components to work with it.

I'm currently facing negative cell volume detected error because of weird mesh deformation, ig I might have made mistake in the dynamic mesh setting but I'm unable to pin point my mistake. Also the simulation occurs for a few time steps with ridiculous values of lift and drag coefficients. I'm attaching below the pictures of deformed mesh, lift, drag coefficient curves, my smoothing and remeshing parameters too. Also I'm using a udf to give motion to the cylinder body. The frequency defined in the udf is 1. I had created a total thickness inflation mesh around my cylinder which is of 5 layers, growth rate of 1.2 and maximum thickness of 0.025. Hence, I first separate the cylinder along with the 5 layered inflation from the surface body, then I give the udf motion to both the cylinder and the 5 inflation layers that I had separated. Kindly help me regarding this issue as I've been trying to solve this issue since past 3 weeks, took reference of changing the time step from various articles but still I get the same error.

We need to provide a boundary heat source to a 2D element. The heat source is periodic with ON time 100ns and time period of 4 microseconds. How to use the inbuilt functions for the the same?

I'm trying to simulate VORTEX INDUCED VIBRATIONS in Flow Around A Rigid Cylinder. The diameter (D) and mass of the cylinder are 0.5 m and 35.78 g, respectively. The spring stiffness is 69.48 kN/m, the damping coefficient is 0.0039 Ns/m and Re=200. I've been trying various UDF since past 2 weeks but everytime m not able to simulate any oscillation so it would be of great help if you kindly provide the UDF.

Gostaria de me apresentar como Editor da RCE-UNITAU, Meu nome é Arcione Ferreira Viagi (http://lattes.cnpq.br/1546647518497478) e tenho a missão de reformular, retomar e fortalecer a revista, nacional e internacionalmente.

Tomei a iniciativa de divulgar no ResearchGate para obter novas submissões de artigos completos inéditos, artigos completos publicados em anais de congressos e relatórios técnicos na área de Ciências Exatas.

Segue uma breve descrição da RCE-UNITAU:

A

**Revista de Ciências Exatas (RCE)**, em versão exclusivamente eletrônica, é uma publicação semestral do programa de Pós-Graduação stricto e lato sensu em Engenharia Mecânica da**Universidade de Taubaté**(SP). Foi criada com os objetivos básicos de atender a demanda para a produção científica das universidades brasileiras e internacionais, visando estimular o debate acadêmico, divulgação, discussão, critica e referencial sobre a evolução e dinâmica das Ciências Exatas em suas diferentes dimensões no âmbito das atividades públicas ou privadas, focando nos aspectos Sociais, Ambientais e Econômicos para o desenvolvimento sustentável. A**Revista de Ciências Exatas (RCE)**é uma revista de orientação pluralista e publica trabalhos que apresentem contribuições originais, teóricas ou empíricas, relacionadas ao campo das Ciências Exatas a um programa de pós-graduação em Engenharia, valoriza o desenvolvimento do diálogo interdisciplinar, abrindo espaços para contribuições de outras áreas (saúde, engenharias, arquitetura, psicologia, história, ciências ambientais) que apresentem interface com o projeto central da revista. Encontra-se disponível para colaboradores nacionais e internacionais e possui um conselho editorial variado, distribuído por várias instituições e regiões do Brasil e de vários outros países.Examples of how to increase the contact surface area of the bottom area? Thank you.

Explicit scheme : By varying the mesh size, we see that for smaller sizes, the computation time for the usual mass matrix (not diagonal) exceeds that of the lumped mass matrix (diagonal). This I understand. But when the mesh size becomes large the computation time for the lumped mass matrix (diagonal) exceeds that of the usual mass matrix (not diagonal). Why ?

Hi :),

I currently am doing a project where I have to analyse the deformation of a circular plate on abaqus , as loads I have added a pressure load and a body force and as boundary condition I have fixed ( encastre). How can I define a deflection on abaqus or what expression can I use in order to input in the software?

thank you in advance

Do

**obstacles**in a channel change the regime from**laminar**to**turbulent**while the**Reynolds number is under 2300**(approximately 1000)?Please introduce related studies.

Hello,

I have several structures which is composed of an upper body and an under body. I want to compare different upper body with each other (therefore several different structures) with Finite element software. I also want to lower the stiffness of these under body to have the same stiffness on the different models and thus be able to compare upper body between them. For this the solution is to vary the Young's Modulus of these different under body. The problem is that some are longer than others in terms of length. How to take this parameter into account?

Method that used in most of automotive industries to detect cracks or damage

One of my friend completed his bachelor degree in mechanical engineering. But now likes to join in computer science engineering related master degree program.

Is it possible to do masters in computer science related courses. If yes, please suggest the courses. Thanking you...

Myself Nekin Joshua R, Research scholar from Vellore Institute of Technology(VIT), Vellore. I need a drop weight testing facility.

Please let me know where it is available in India ( Preferably nearer to Tamilnadu and also suggest the testing facility all over india).

Hi all

Sometimes the flashing process are calculated with mass and balance equations like the following link:

But sometime the flashing process are calculated with "non equilibrium allowance"(NEA) like MED or MSF desalination

Why?

I am simulating a solar powered absorption chiller. But I want to manipulate ots working time. For example, the system will run from 6 am to 10 am, then a break of 4 hours and then again run for four hours and then stop. How do I achieve this ?

Wake formation has been largely observed behind objects in real use e.g pillars, vehicles, buses, cars and building.

It has also been regions of large interest over decades.

So the question here is ? what are disadvantages of wake formation?

why they are so important?

I want to simulate mixing

**two fluids**with different**inlets and velocities**in**COMSOL**. I used "**Laminar Flow**" and "**Transport of Diluted Species**" physics to do it, and my problem is that I cannot select both fluids for my domain. I have two fluids and one domain for mixing. How can I do it? Should I use "**Multiphase Flow**" physic?I am looking to desigtn and simulate a vertical pressure vessel holding 10 m3 of pressurized Liquid Propane Gas (LPG) by following the American Society of Mechanical Engineers (ASME) standard for the design. The pressure vessel in this study is cylindrical with two elliptical heads, two nozzles, a manway and four legs support. I have seen different publications where is not clear about applying the pressure. In some publication is mentioned that they apply hydrostatic pressure and other normal pressure or both.

Any idea, suggestion or recommendation will be much appreciated.

Minimum Quantity Lubrication (MQL) is a theoretically and practically proven technic. When MQL is adopted in a production sector, for example (any machine tool-Lathe, Milling, Grinding, drilling), what are the challenges faced (Pros and Cons)?

In many cases, the experimental work was compared with the simulation or else similar experimental results from literature based on percentage increment or decrement. In most of the cases, we compare similar results as one had obtained.

Why don't they compare with results which differ from his/her results?

All the time results may not agree with the literature.

Is it good to defer the results in the publication?

What should do when you haven't gotten results which don't agree with existing?

Hi,

I'm conducting compressive mechanical tests on jello material on a rheometer HR20 by TA Instruments. The cross hatched top plate is 8mm in diameter and circular in shape.

I'm testing hockey puck shaped jello samples ( 8mm in diameter, 2mm in height) and calculated the area under the curve given by the software.

1. I'm getting results as Pa %. Don't the numbers seem too high for a small soft sample? (I triple checked my input dimensions and down speed).

2. I generated another graph from the same data with um on the x axis instead of %. The numbers make more sense this way but I need help equating between this value and the one from the first graph(as they should be the same when manipulating units).

3 To my understanding, area under the curve is toughness which should be provided in units as J/mm3. Does anyone know how to convert the values from the previous 2 questions to J/mm3?

Please help if you understand this problem, it is greatly appreciated!

How can I calculate

**ANOVA table**for the**quadratic**model by**Python**?I want to calculathe a table like the one I uploaded in the image.

Hello everyone,

I want to investigate the debonding behavior of the matrix-particle interface in a particulate composite with spherical particles in a two-dimensional matrix, using the Abaqus Dynamic Explicit solver.

I used General Contact (Explicit), with cohesive behavior and Johnson -cook damage formulation. However, stress concentration is occurred at matrix, and the stress is not transferred to the particles. Also, interface perpendicular to force direction is deboned very early. I think my interface definition is not correct, any help would be highly appreciated.

I am an undergraduate student. My major is naval architecture and offshore engineering.

My interested research area is shipbuilding, production/ field basis, structure.

I question is welding is a good topic for thesis ?

Or suggest me a good topic.

Thank you

I am struggling in finding the proper literature on the topic. please help me. Thank You.

Which software is best for making high-quality graphs? Origin or Excel? Thank you

I am having some project ideas. I like to convert into reserch proposal and apply for sponsored project.

Please tell me the way to apply for sponsored project like DST, DRDO sponsorship.

Anyone working with QFORM software please guide me to re-run the simulation process after modifying the input parameters. or please suggest some alternate solution to continue with the simulation without losing previous result

I like to pursue my Ph.D in Mechanical Engineering with Stipend.

Please suggest the university in india and other global universities.

Please help.

When I try to perform the following calculation, Python gives the wrong answer.

**2*(1.1-0.2)/(2-0.2)-1**

I have attached a photo of the answer.

Hi

I have a problem where I am trying to vary the stiffness spatially across a structured interface. The whole idea is to vary the stiffness vertically, with a bulk stiffness of 8GPa decreasing smoothly over 100 micrometres to 2GPa. To achieve this I have been using the USDFLD subroutine in Abaqus to create a functionally graded material. The base Fortran code Ive started with is attached as txt file.

To vary the stiffness I have created a field variable to relate Young's modulus to the y-coordinate system which would be really easy to get the desired result if it was just one part (as shown in the contour plot). The main issue I have with varying stiffness when both parts are present in the assembly is the area where these intersect each other vertically prevents my current code from working. Im very new to using subroutines, I think it should be fairly easy to create a code to enable the stiffness to vary for both identical parts.

The code I have works for one part, so would it be possible to take the functionally graded component and export it as a part and then assemble and add boundary conditions from there?

Any help would be greatly appreciated!

Alex

Are there any problems in Dental Science especially in the field of Dental Composites and Nanocomposites or Dental materials in general that a Mechanical Engineer or Material Science researcher can solve or research upon ?

Hello,

I'm trying to do a simulation on a simple 120mm piece. I defined a displacement of 1mm on one side and fixed the part on the other side. I have defined 50 substeps with large deflection on.

To plot the graph I've got the reaction force of the displacement and divide by the area of stress in y axis and I've got the dispacement divide by the lengh in x axis.

I only have the linear part of the graph and I don't know how to get the whole graph with the plastic region.

I appreciate any suggestion

Thank you for your help

In the filename.trace output file I find there are multiple cycles of temperature appearing say 50-800 with their corresponding output. I want to know how should i analyse this data and which of the cycles should i consider?

hello

I have problem with comsol multi physics. I have a model to simulate natural convection in air enclosure with hot pipes emended. First of all, I did not get convergence at all even though the model is an experimental model, it has been done before by FLUENT. I've tried many many things to get convergence, but i failed. Recently, I've tried on thing. I changed the value the value of the viscosity of the air into (0,001) ( it is obviously illogical because the viscosity of the air at the operating temperature in the tables is about 1.8e-05) at this value I get convergence with the results very close to those that have been done by FLUENT before!!! that is kinda of odd. have any one had same problem before??or does anyone have an explanation why I got convergence when I increased the value of the viscosity?????. Attached is the comsol file has been done by comsol 4.3

Is there an index that includes the

**mixing index**and**pressure drop**for**micromixers?**For example, for heat exchangers and heat sinks, there is an index that includes heat transfer performance and hydraulic performance, which is presented below:

**η**

*=(Nu/Nu*_{b})/(f/f_{b})^{1/3}The purpose of these indexes is to create a general criterion to check the devices' overall performance and investigate the parameters' impact.

Is there an index that includes

**mixing performance**and**hydraulic performance**for**micromixers?**I want to make two parts in abaqus that are on each other like two different cubic boxes. Think these two parts are linked in a way that when one box is rotating around a point (point not on the center of the cube) the second box is translating with the first box. This means the first box is rotating and the angles of the part with respect to the global coordinate system is changing however the second box angles are not changing with respect to the global system and is just translating according to it. I want to apply this by connectors but if you think of any other way please let me know.

Many thanks in advance.

Which is the most crack direction is studied in a metal cantilever beam? When the crack is vertical or horizontal? (I mean if the crack propagates vertically or horizontally?)

And how each type of excitation(Bending, Axial,..) is sensitive for each type of crack shape and orientation?

I am asking for test purposes .. So I can use the crack direction that is more sensitive for measurements in my experiment.

Yesterday night, I was working on some model in ABAQUS and all of a sudden it gets shut down. When I tried to reopen the model, it was not opening and since then every time I try to reopen it, it always creates new model on its own without showing any of the previous contents of the old model.

Although *.cae file is still of the same size (around 233 MB) and *.jnl file is also there. But I don't know how to run that *.cae file and recover the old model. I would really appreciate any kind of assistance in the above matter as it represents around 6 months of work.

Thanks in advance.

Is there any effect of damage shape on the damage severity? And which do you expect has more severity of damage the holes shape or longitudinal shape? And why?

The 2023 ranking is available through the following link:

QS ranking is relatively familiar in scientific circles. It ranks universities based on the following criteria:

1- Academic Reputation

2- Employer Reputation

3- Citations per Faculty

4- Faculty Student Ratio

5- International Students Ratio

6- International Faculty Ratio

7- International Research Network

8- Employment Outcomes

- Are these parameters enough to measure the superiority of a university?

- What other factors should also be taken into account?

Please share your personal experience with these criteria.

How can I import

**2D**sketches from**CATIA**into**COMSOL Multiphysics**?The formats that COMSOL reads in 2D geometry are not available in CATIA.

I am looking for useful proposals for doctoral research in the field of internal combustion engines (thermal engineering).

I have previously conducted laboratory experiments on a photovoltaic panel under the influence of artificial soiling in order to be able to obtain the short circuit current and the open-circuit voltage data, which I analyzed later using statistical methods to draw a performance coefficient specific to this panel that expresses the percentage of the decrease in the power produced from the panel with the increase of accumulating dust. Are there any similar studies that relied on statistical analysis to measure this dust effect?

I hope I can find researchers interested in this line of research and that we can do joint work together!

**Article link:**

when I tried to simulate a tesla valve with the compressible turbulent fluid flow for hydrogen (single-phase standard k-ε turbulent physic and heat transfer in fluid physic are used, and the study is stationary), I got the following error:

"Undefined value found.

- Detail: NaN or Inf found when solving linear system using SOR line."

What is the problem?

I need to know what are the kind of loads the vehicle is subjected to while cornering, braking and braking with cornering?

I am looking for a method to select a specific size of silica particles (spheres) from a broad range of mixture with different particle size. I need to be selective in the cut-off. I have tried mechanical sieving both in dry and wet form, but its quite laborious, time consuming and lot of water wastage (wet sieving). Can any one suggest any equipment or method for large scale separation (around 10 Kg) ?

Hi

i am working as a lecturer in the department of Mechanical Engineering in Pakistan institute of engineering & technology. I have to assign complex engineering problems in my teaching course which is manufacturing processes.

**Topic Details:**

Forming & shaping processes and equipment, material removal, cutting tools, machining processes for producing various shapes, extrusion and drawing, sheet metal forming, forming & shaping plastics & composite materials.

**Please suggest complex engineering problems from the above mentioned topics**

Tensile strength performance and optimization of Al 7068 using TIG welding process is done by the previous researcher.

Please suggest the aluminium or stainless steel material other than Al 7068 for my future project. I like to follow the same methodology of previous researcher. But changing the material.

I am Ali Raza student of Mechanical Engineering. I am working on a project in which i have to make a hole in microwave oven and i have a few queries.

1. Which method is best for cutting a hole in oven?

Note. I tried but lasor and plasma cutting didn't work

2. Is there any difference making a hole on upper side and lower side?

If anyone know about my queries your answer will be highly appreciated

I have two tubular geometries namely outer tube and inner tube. Initially they are not in contact but when load is applied on the outer tube it will get deform and collide with the inner tube. One end of both the tube is fixed.

I have shared my geometry image file.

What are the required technical specifications of Polyethylene, that can be used to make the wires and cables?

Previously I have been working on the topology optimization of a mechanical component but due to the recent interest in generative designs I want to compare the geometry I obtained via topology optimization with the generative design geometry. In the initial research I observed that generative design is mostly used for architectural structures. So, I wanted to ask about the scope of such work for mechanical components/systems. And is it possible to obtain generative design using of mechanical components that are manufactured using subtractive manufacturing techniques such as machining.

In Comsol software, we use the two physics

**"Heat Transfer in Porous Media"**and**"Heat Transfer in Solids and Fluids"**to study the heat transfer from a**porous**part to**solid and fluid**areas. The problem is that the interface between the porous and fluid or solid areas in both physics is defined as thermal insulation. How do we define these common areas boundary conditions to establish the heat transfer between the porous and solid or fluid areas? In some numerical studies, they used the**heat flux**boundary conditions for the common areas of the porous and fluid sections. Still, I do not think this boundary condition is appropriate.My brother is doing B.E Mechanical Engineering. He need a methodology to do a final year engineering project. He needs a Simple Project guide book. Please mention the book name with simple instructions.

I have a simulation code for a

**Horizontal Washing Machine.**The code solves the equations of motions of the system by

**Matlab ode45**and plots the**vibration response**of the system at the**transient state**of performance.In this code, the frequency (

**omega**) is an**exponential**function of time, as it's stated below (and its diagram is attached to 'the question'):-------------------------------------------------------------------------------------------------------------------------------------------------------

omega= (1-exp((-0.5)*t))*omega_0+(1-exp((-0.5)*heaviside(t-t1).*(t-t1)))*(omega_1-omega_0);

-------------------------------------------------------------------------------------------------------------------------------------------------------

**ode command:**

-----------------------------------------------------------------------------

[T,Y]=ode45(@snowa1,tspan1,initial_vector1);

plot(T,Y(:,1)-mean(Y(:,1)))

-----------------------------------------------------------------------------

**The resulting displacement response is attached to the question.**

**It is desired to**:

**First**, increase the frequency to omega_0 by exponential1

**Then**, increase it to omega_1 by exponential2

**But 'the problem' is**that:

the displacement response shows an

**unexpected increase in frequency**at the beginning of the second exponential increase (it**becomes 20 Hz,**which is much larger than the maximum frequency in the simulation- 10 Hz).Do you know what could be the reason for this response?

Any help would be gratefully appreciated.

Can anyone suggest to me method to design fuzzy inference system (FIS) for MIMO structural damage detection (i.e. data distribution on the membership function, parameters of MF, Generate rules ... etc )

In my system there are 3 inputs and 2 outputs:

Inputs: Relative 1st Natural frequency , Relative 2nd Natural frequency , Relative 3rd Natural frequency

Outputs: Crack depth ratio , Crack Length

Note: I tried to use "genfis" By MATLAB it didn't give me reasonable results.

Any references or articles that describe that accurately.

Generally observed at low strain rate for fine grained material.

For industrial scale

which are viable materials?

which parameters need to alter?

Kindly express your views.

Jerk is defined as the rate of change in acceleration. But I would like to know some practical applications of Jerk inorder to have better understanding. I kindly request to suggest me some examples.

Kindly express your views what we can decipher from Storage modulus and tan δ.

w.r.t. to failure mechanism, tribological performance etc.

As every keyword have certain experts associated with it, based on their area of expertise. Can we initiate a devoted section for research collaboration, especially for the calls requiring bilateral or multinational collaborator?

Presently, My group is looking for a German collaborator in the area of " High performance based C-C composites" on following call "http://www.dst.gov.in/sites/default/files/DST-DFG-JointCall-10AUG2018.pdf"

Finding it difficult to have a relevant and interested group from Germany. kindly text me if anyone finds this call interesting.

Please share how I should proceed to search for interested researchers from Germany, My present approach is searching research papers on said area and mailing to the researcher if find relevant.

Dear Ehsan, hi!

I read a work done by your team on flameless combustion and it is very interesting. I work in a steel company in Sweden, where our furnaces are equipped with flameless oxyfuel. I need to calculate the recirculation factor for this type (for my next publication).

My question is how the formulation in your paper applies to oxy-propane flames? Can you help me with this?

Thank you in advanced

/Mersedeh Ghadamgahi

If a model of beam without damping is considered we obtain the real natural frequencies. However, I would like to ask what shall be the nature of the natural frequencies if we consider the rotary inertia of the beam? Whether they will be real or complex?

As a beginner, it is a challenging task for me to choose a goo