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# Mechanical Engineering - Science topic

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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
Seems fine to me. Step 6 will tell you if you did it right. The residual should be small, and also shouldn’t show any low order structure that seems too similar to any of the fit zernikes.
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For a regular Low Temperature Striling Engine, how much mechanical energy can I produce by using hot water at around 350K?
The mechanical energy produced by a Stirling engine using hot water at around 350K depends on factors like engine efficiency, temperature difference, and design. Generally, small engines might produce a few watts, while larger ones can generate several kilowatts or more. Specific values vary based on these factors.
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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.
The Rayleigh number (Ra) is a dimensionless number used to predict the flow regime (conduction, convection, or mixed) in a fluid when it is heated from below. In the context of a phase change material (PCM)-heatsink system with fins, the characteristic length is an important parameter for calculating the Rayleigh number.
The characteristic length (L) used in the Rayleigh number calculation can vary depending on the geometry of the system. In the case of a PCM-heatsink with fins, the characteristic length can be defined based on the specific geometry you are dealing with. Here are a few possibilities:
1. Fin Height (H): If the characteristic dimension of interest is the height of the fins (assuming they are vertically oriented), you can use the height of the fin as the characteristic length. This would be suitable when the heat transfer is mainly driven by natural convection along the fins.Rayleigh Number (Ra) = (g * β * ΔT * H^3) / (ν * α)Where:g: Acceleration due to gravity β: Coefficient of volumetric expansion ΔT: Temperature difference between the heated surface and the surrounding fluid ν: Kinematic viscosity of the fluid α: Thermal diffusivity of the fluid
2. Fin Base Width (W): If the characteristic dimension is the width of the fin base, you can use this value as the characteristic length. This might be more appropriate if the heat transfer occurs primarily through the base of the fins.Rayleigh Number (Ra) = (g * β * ΔT * W^3) / (ν * α)
Remember that the choice of characteristic length depends on the dominant heat transfer mechanism in your specific setup. The key is to select a length scale that is relevant to the phenomenon you are trying to analyze.
Additionally, when dealing with PCM systems, keep in mind that the melting and solidification of the PCM can introduce additional complexity to the heat transfer process. You might need to consider the effects of latent heat and phase change in your analysis.
Before performing calculations, ensure that the physical properties of the fluid, PCM, and the geometry are accurately determined. It's recommended to consult relevant literature, research articles, or textbooks in the field of heat transfer to find appropriate values and guidance for your specific configuration.
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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?
Thank you Mr. Kim for replying
Under the Eulerian Model, a drag model is to be chosen, what is the appropriate drag model to be used for such simulation?
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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.
Cantilever Design and Materials:**    - Use smaller and stiffer cantilevers: Smaller cantilevers have higher resonant frequencies, allowing for faster scanning without compromising sensitivity.    - Explore novel materials: Cantilevers made from materials with higher stiffness and lower thermal noise can improve both speed and resolution. 2. **Advanced Tip Technology:**    - High-quality tips: Utilize sharper and smaller tips for improved resolution and reduced tip-sample interaction forces.    - Functionalized tips: Attach functional molecules or nanoparticles to the AFM tip for enhanced specificity and contrast. 3. **Feedback System Optimization:**    - Advanced control algorithms: Implement advanced feedback algorithms that minimize settling time, reduce artifacts, and optimize scanning trajectories.    - Model-based control: Use predictive models to anticipate and compensate for tip-sample interactions, enabling faster scanning while maintaining image quality. 4. **Dynamic AFM Techniques:**    - Frequency modulation AFM (FM-AFM): This technique minimizes tip-sample interaction forces and can enhance resolution while maintaining high-speed scanning capabilities.    - Multi-frequency AFM: Simultaneously excite multiple resonances of the cantilever to extract additional information and improve imaging speed. 5. **Parallel Scanning:**    - Array-based AFM: Develop AFM systems with multiple cantilever arrays or probes, enabling simultaneous imaging of multiple areas on the sample surface.    - Fast z-scanning: Implement rapid vertical scanning mechanisms to reduce the time required for three-dimensional imaging. 6. **Real-time Imaging and Analysis:**    - On-the-fly data analysis: Process and analyze data during scanning to adjust imaging parameters in real-time, optimizing imaging conditions for speed and resolution.    - Adaptive scanning strategies: Adjust scanning parameters dynamically based on the sample's topography to focus on regions of interest. 7. **Automation and Software Improvements:**    - Automated image stitching: Develop software that automatically stitches together multiple scans to create large-area, high-resolution images.    - AI-driven image reconstruction: Utilize machine learning algorithms to enhance image quality and extract information from noisy data. 8. **Sample Preparation and Environment:**    - Controlled environment: Maintain stable temperature, humidity, and vibration conditions to reduce thermal drift and other sources of noise.    - Sample treatment: Optimize sample preparation techniques to minimize surface roughness and improve the quality of the images. 9. **High-Speed Scanners:**    - Piezoelectric actuators: Utilize high-speed, low-noise piezoelectric scanners for rapid tip movement with minimal mechanical noise. 10. **Non-contact and Tapping Mode AFM:**     - Non-contact AFM: Operate in non-contact mode to minimize tip-sample interaction forces, reducing the risk of sample damage and achieving higher resolution.     - Tapping mode: Utilize tapping mode to scan samples while intermittently contacting the surface, reducing wear on the tip and sample. Remember that advancements in AFM technology often involve a trade-off between speed and resolution, so careful consideration of the specific imaging goals and sample characteristics is crucial when implementing these strategies.
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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.
specific changes that you can make to your dynamic mesh settings:
• Increase the mesh size. This will help to reduce the amount of distortion in the mesh.
• Increase the frequency of the dynamic mesh updates. This will ensure that the mesh is updated more frequently, which will help to prevent it from becoming too distorted.
• Adjust the remeshing parameters. This will help to ensure that the mesh is updated in a way that minimizes the negative cell volume errors.@Muthiah CT
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Renewable energy
While increasing load on the engine brake power increases more than the fuel consumption so bsfc decreases
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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?
You can use the sin function.
if(sinwt>0,source,0). (please recheck the syntax of the if function).
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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.
What software do you want to solve the problem? Fluent? CFX?...?
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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:
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Examples of how to increase the contact surface area of the bottom area? Thank you.
The following article regarding apple cultivars are relevant to this case:
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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 ?
And why sparse matrix has computational benefits than diagonal matrix for large sizes ?
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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?
1) At first , you have to create the model by defining the properties and geometry of the model.
2)Then mesh the model and apply the appropriate boundary conditions to simulate the loading and constraints in your analysis.
3)After this for adding a deflection expression, you can use the Abaqus Expression Language (AEL) or Python scripting.
4)You can create an expression by navigating to the "Model" module and selecting "Expressions" from the drop-down menu.
5)Then in "Model" module, select "Output Requests" and create a new request such as displacements or strains, and set the "Component Scope" to the desired direction of deflection. In the "Expressions" section of the request, assign your deflection expression to the appropriate variable.
6) Then just run the analysis and post processing for extract the deflection result.
I think these steps helps you to solve your problem.
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Do obstacles in a channel change the regime from laminar to turbulent while the Reynolds number is under 2300 (approximately 1000)?
The Reynolds number UD/nu=2300 is based on a smooth circular pipe of diameter D, with STEADY mean flow velocity U and fluid of kinematic viscosity nu. Below this critical Reynolds number any perturbation due to an obstacle will not cause persistent turbulence to occur far downstream of the obstacle. Of course locally the wake of a blunt body placed in the pipe can be turbulent, but soon the flow will relaminarize if we travel further downstream. Above Re=2300 the flow does not need to be turbulent. It can be turbulent if there is a sufficiently large initial upstream perturbation. In principle the flow can remain laminar if the inlet is very smooth and care is taken to avoid vibrations. Experimentally fully developed laminar pipe flows have been achieved for Re=500. 000. It is important to realize that this critical Reynolds number does depend on the geometry of the cross-section of the channel. For a rectangular channel of height h and width w >>h, usually one considers a Reynolds number Re=Uh/nu based on the channel heigth. The critical Reynolds number for allowing turbulence is around Re=hU/nu=1100. There is however much less literature on flows through slit shaped channels than circular pipes. If you consider an open channel flow, clearly the critical Reynolds number will be quite different from Re=2300 and of course it does depend on the length scale used in the definition of this Reynolds number!
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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?
Hi
Does that mean you want to compare different bodies with a fixed underbody? If so, can't you consider the underbody rigid in your software? If not, can you ask your question more clearly?
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Method that used in most of automotive industries to detect cracks or damage
There are several methods used in the automotive industry to detect damage or cracks, depending on the type of material and the location of the potential damage. Here are a few examples:
1. Visual inspection
2. Liquid penetrant testing
3. Ultrasonic testing
4. X-ray inspection
5. Magnetic particle testing
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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...
Dear, it's not possible to do master in computer science after mechanical graduate.
But heay try to robotics, automobile and other computer related course which is the available in Mechanical Engineering domain.
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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).
Drop Weight Impact Testing Machine is available in VIT it self. Please verify it once again before going 2 other college sir. All the best.
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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?
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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 ?
Dear Auritro Samanta,
Maybe my answer is too late for you. However, it can be helpful to others.
One option to manipulate TRNSYS simulations is by the 'dck' file that can be generated from the TRNSYS model (the tpf file).
The dck file is a plain text command line file, which TRNSYS reads and executes the codes.
TRNSYS can be started from the prompt to execute a dck file by the following command: <[trnsys_path] [dck_file_path] /h>.
The </h> will hide the trnsys window, and it will be executed in the background.
Thus, you can write the tpf model with some tags, generate the dck file, search in the dck for the tags that you used, and then replace the tags with the values you want to use.
I hope this can be helpful to someone.
Kind regards,
André.
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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?
Thank you Gaurav for your interest.
In aerospace the wake has always been a disadvantage from the design point. But is it possible to use it for solving the problem, or designing a device, may be the cooling mechanism.
Using the problem itself to generate the solution. Reverse engineering if I m correct.
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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?
Yes, you have to define a multi-phase model, e.g., VOF or Euler-Euler.
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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.
Hi,
you should use design pressure for numerical simulation plus the hydrostatic pressure of the liquid. Design pressure is a conventional number that is greater than or equal to working pressure. For this case, I guess working pressure shall be at least the saturated pressure of LPG or a few kPa higher.
Regards
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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)?
Adoption of Minimum Quantity Lubrication (MQL) in a production sector, such as machine tools (Lathe, Milling, Grinding, Drilling), presents both advantages and disadvantages.
Pros of MQL include:
1. Lower cost: MQL uses smaller amounts of lubricant compared to conventional lubrication methods, reducing the cost of lubricant and waste disposal.
2. Improved tool life: MQL reduces friction and wear on cutting tools, extending their life.
3. Improved surface finish: MQL produces a cleaner, smoother surface finish on the workpiece.
4. Increased sustainability: MQL reduces the amount of lubricant and waste, leading to a more sustainable production process.
Cons of MQL include:
1. Difficulty in controlling the flow rate: The small amount of lubricant used in MQL makes it difficult to control the flow rate, leading to potential inconsistencies in the machining process.
2. Complex setup: The setup of MQL systems can be complex and may require specialized equipment.
3. Limited range of applications: MQL may not be suitable for all types of materials or machining processes.
4. Need for frequent monitoring: The small amount of lubricant used in MQL requires frequent monitoring to ensure that the right amount is being applied.
It is important to consider both the advantages and disadvantages of MQL when deciding whether to adopt this technology in a production sector. An in-depth analysis of the specific machining process and material being used, as well as a thorough evaluation of the available MQL systems, can help determine if MQL is a suitable choice.
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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?
A hundred year omission from the yes men in physics:
Since by definition frequency=1/(time period) and all Doppler shifts (axial, transverse and gravitational) change all observed frequencies on an object by same factor K. They should all change all observed time periods by 1/K on that body. NOT JUST the transverse Doppler shift of relativity. Because the above has not been obvious for some time. The attached PDF file has in it a proof of the same by comparing the Fourier series of a time function with series of the Doppler shifted function. It also gives some impacts of that. Most impacts are in high energy physics. Also note factors in observing the above: Accelerators generate noise many ways (like fast moving particles transfer energy to standing waves etc.) . The axial shift has an average over all angles of zero but for most angles it is lager than the transverse. But the variance of axial shift does have a mean over all angles above zero.
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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?
Regarding the 3rd question, the area under curve represents toughness (amount of work done /unit volume) of material specimen, In you case it is 96.1kPa %. The tensile strength is however, ~580.1 kPa = ~ 0.6 MPa. and the Youngs (elastic) modulus is ~ (580.1 /95.5)*(100/1000) = 0.61MPa
However, i am not sure if there are direct conversion units from Pa% to J/mm^3 .
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Sand processing capacity 2T/hour
Apologies, I know this is an old thread but I have a research paper that might be of some interest related to sand reclamation and that is to look outside the business at businesses that might be able to re-use the reclaimed sand.
Best Regards
Martin
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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.
To calculate an ANOVA (Analysis of Variance) table for a quadratic model in Python, you can use the statsmodels library. Here is an example of how you can do this:
#################################
import statsmodels.api as sm
# Fit the quadratic model using OLS (Ordinary Least Squares)
model = sm.OLS.from_formula('y ~ x + np.power(x, 2)', data=df)
results = model.fit()
# Print the ANOVA table
print(sm.stats.anova_lm(results, typ=2))
#################################
In this example, df is a Pandas DataFrame that contains the variables y and x. The formula 'y ~ x + np.power(x, 2)' specifies that y is the dependent variable and x and x^2 are the independent variables. The from_formula() method is used to fit the model using OLS. The fit() method is then used to estimate the model parameters.
The anova_lm() function is used to calculate the ANOVA table for the model. The typ parameter specifies the type of ANOVA table to compute, with typ=2 corresponding to a Type II ANOVA table.
This code will print the ANOVA table to the console, with columns for the source of variance, degrees of freedom, sum of squares, mean squares, and F-statistic. You can also access the individual elements of the ANOVA table using the results object, for example:
#################################
# Print the F-statistic and p-value
print(results.fvalue)
print(results.f_pvalue)
#################################
I hope that helps
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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.
To define debonding at the matrix-particle interface using the cohesive surface method in Abaqus, you can follow these steps:
1. Create a surface or surfaces in your model that represent the interface between the matrix and the particles. These surfaces should be associated with the matrix material.
2. In the Abaqus/CAE interface, go to the "Material" tab and select "Cohesive Surface" from the "Material Type" dropdown menu.
3. Define the cohesive surface properties, such as the normal and tangential stiffness, normal and tangential strength, and debonding energy. These values should be determined based on the material properties of the matrix and the particles and the desired debonding behavior.
4. Assign the cohesive surface material to the interface surfaces in your model.
5. Run the simulation and monitor the debonding behavior at the matrix-particle interface. You may need to adjust the cohesive surface properties and re-run the simulation if the debonding behavior is not as desired.
Keep in mind that the cohesive surface method is just one approach to modeling debonding in particulate composites. Other methods, such as the cohesive element method, may also be used depending on the specific needs of your simulation.
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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
There are many potential topics for a thesis in naval architecture and offshore engineering, and the best one for you will depend on your interests and the resources available to you. Here are a few potential topics to consider:
1. Welding techniques for shipbuilding: This could involve researching and comparing different welding techniques and materials, and evaluating their effectiveness and cost-efficiency for use in shipbuilding.
2. Ship design and optimization: You could investigate ways to optimize ship designs for different purposes, such as fuel efficiency, cargo capacity, or seakeeping performance.
3. Offshore structures: There are many different types of offshore structures, including oil and gas platforms, wind turbines, and wave energy converters. You could focus on the design, construction, or maintenance of these structures.
4. Production processes in shipbuilding: This could involve studying ways to improve efficiency and reduce waste in shipbuilding, such as through the use of advanced manufacturing techniques or lean manufacturing principles.
5. Shipyard operations and logistics: You could research ways to optimize shipyard operations, such as through the use of advanced planning and scheduling techniques or the implementation of new technologies.
6. Ship stability and seakeeping: You could investigate ways to improve the stability and seakeeping performance of ships, such as through the use of advanced hydrodynamic modeling techniques or the development of new hull forms.
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Saurabh Deshmane , condition monitoring and on-line diagnostics in real time is possible thanking to IIoT.
With the arrival of the Fourth Industrial Revolution (or Industry 4.0), pneumatics continue to evolve at a pace previously unseen. And what is powering this revolution are, among other things, advances in smart technology that connect industrial machinery and devices to the internet in an effort to facilitate automation and transmit data in real time. This is commonly referred to as the Industrial Internet of Things (IIoT). In fact, as connectivity becomes increasingly common in everyday life, growing numbers of manufacturers and industry leaders are upgrading their machinery to become part of the IIoT...
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Which software is best for making high-quality graphs? Origin or Excel? Thank you
origin
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I am having some project ideas. I like to convert into reserch proposal and apply for sponsored project.
to get sponsorship and grant details one can get from the community of chapters managed by the professors, and scientists. Provide the right link and ways to the people to get the right funds from the country. get at https://abcdindex.com/society_page_post_listing.php?type=Sponsorship
They have some expert lectures on that so people can take advantage of that as well.
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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'm new to the drawing process and I'm looking for the software QForm to conduct some analysis in my research.
I would like to know where I can find the software to download?
Deendayal Kumar or Karim Amellal do you have the instalation setup of this software to share with me?
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I like to pursue my Ph.D in Mechanical Engineering with Stipend.
Please suggest the university in india and other global universities.
National University of Malaysia
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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.
Mathematically, the answer to the equation is zero; the answer Python spat out is pretty much as close as you can get to the representation of zero with a typical computer.
This is a classic floating point problem: https://en.wikipedia.org/wiki/Floating-point_error_mitigation
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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
Hi,
You may be interested in our new article on modeling FGM in ANSYS APDL.
We are eager to have your feedback.
best regards.
Ahmed Hassan Ahmed Hassan
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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 ?
As Dental practice requires a large inventory, all materials, instruments and equipments can be innovated, improved and tested using principles of Mechanical engineering and material science researchers. The discussion about new restorative material is visible in this group. However we should also think of newer materials for root canals which can match ideal requisites as well as are easy to manipulate. 3D imaging, impressions, printing, milling methods, its properties, stress distribution during function, longevity, fatigue etc can be done. There is whole world of possibilities with Finite Element Analysis.
Moreover designing new instruments with minimal likelihood of discomfort to patients and can help in best manoeuvring the oral tissues as well as materials being used in oral cavity. New designs of tongue, cheek and lip retractors which enable holding of suction tips as well as help in keeping mouth open and stabilising the head. So new retractors for use during soft tissue laser procedures. New materials which can be quickly disinfected/ sterilised? New equipments like design of dental chair lights for better visibility. Lights can be integrated in instruments/ retractors for better visibility.
The list is endless with out of box thinking for dental chairs design, operatory design, placement of operating tray near patient's mouth.
We may even design new autoclaves with specific modifications for sensitive dental instruments.
We can turn our directions into having environment friendly dental materials and consumables. The disposables used in dentistry are largely made of plastics and non recyclable materials as on now. There is a need to think about environment friendly alternates etc.
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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
Hello, first, thank you all for the answers it helped me a lot and I finally found a way to simulate what I wanted, you where right about the displacement, it wasn't enough at first.
And my geometry looked more like the picture appload :
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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?
choose the set of data at E-Ef closest to zero.
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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
I hope to find the answer in the following pdf
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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/Nub)/(f/fb)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?
Dear
Rani P Ramachandran
Thank you for your answer. I think mixing energy cost (MEC) is the index that I look for it.
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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.
Dear all,
I am trying to define a connector element between two nodes located at the junction of a two-layer beam.
Each of these two layers has different properties. But the coordinates of the two selected nodes are the same. Can you help?
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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.
I think it depend on the type of load applied.
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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.
I met the same problem any message does not pop up when I run the abaqus. However, as I make a job and try to save the job, I face the same error" rfm_StringManagerFile::String - String is not available".
I tried to recover jnl and cae file using command window but it has not worked.
Please let me know how I can resolve the issue!!!
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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?
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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:
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?
Cenk Tan; There are, of course, several websites that rank the universities worldwide. However, QS is the most famous of which.
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How can I import 2D sketches from CATIA into COMSOL Multiphysics?
The formats that COMSOL reads in 2D geometry are not available in CATIA.
You can import your 2D model from CATIA software into AutoCAD software and write output DXF.
Good luck!
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I am looking for useful proposals for doctoral research in the field of internal combustion engines (thermal engineering).
Hello dear Hiba Arous,
Internal combustion engines are heat engines whose heat transfer plays a very important role in their performance and efficiency. In an internal combustion engine, the cooling system is responsible for dissipating excess engine heat. The cooling system of an internal combustion engine consists of many components, one of which is the cooling passage of the cylinder block and the cylinder head. Therefore, you can focus on the effects of the new design of the cooling inlet and outlet position on the engine body temperature distribution and pump power.
Although this is not related to my field of expertise, I recommend it based on my experience working with internal combustion engines.
Good luck!
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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!
Dear Dr Younis
Find attached:
1-(1) (PDF) Spatial Management for Solar and Wind Energy in Kuwait (researchgate.net)
2-(1) (PDF) Cost and effect of native vegetation change on aeolian sand, dust, microclimate and sustainable energy in Kuwait (researchgate.net)
regards
Ali Al-Dousari
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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?
Bonjour, one of the reasons is the type of mesh implemented and the computer processor you use. To solve these types of equations your computer must be powerful. I recommend you to work with as few meshes as possible.
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I need to know what are the kind of loads the vehicle is subjected to while cornering, braking and braking with cornering?
When cornering, the vehicle is subject to a centrifugal force - i.e. transverse to the car - which must be balanced by transverse forces of adhesion. This force pushes the vehicle away from the road and forces it to follow a straight path. Its mathematical formula is FC = mv²/R. It causes the vehicle to skid and roll over. Like kinetic energy, it increases with speed. The tighter the turn, the greater the centrifugal force. The risk of skidding is therefore very high.
When braking, the car is subject to an inertial force. The braking distance is proportional to the vehicle's kinetic energy and varies with it. The vehicle, during its braking phase, is subject to three forces: its weight P, the force exerted by the ground, perpendicular to it, of the same value as the weight of the vehicle.
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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) ?
What would be the easiest method to separate silica particles of different particle size in large scale?
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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
Do you need problem statement for research?
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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.
You can try TIG to weld aluminum alloys AA6082
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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?
I think where the holes are, it doesn't matter if they are up or down
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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.
Hello, I'm having the same problem. Were you able to find a solution? Can you help me ?
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What are the required technical specifications of Polyethylene, that can be used to make the wires and cables?
It depends on whether you plan to use it as an insulating or a jacketing compounds and it also depends on whether it is for AC or DC application, if AC, whether it is power frequency or telecommunication cable (high frequency) and what is the voltage level. Please be more specific.
I attach a preprint chapter from a book I am working on.
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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.
The perspective is different. Topology optimization is aimed at optimization while generative design more at conceptualization, when different forms are explored
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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.
Bonjour, I think you should activate the extra dimension that is available when you use a porous medium in COMSOL. Coupling of "Heat Transfer in Porous Media" and "Heat Transfer in Solids and Fluids" at boundary conditions.
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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.
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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.
I understand that the 4DOF system for the washer can be quite lengthy. However, I'm unsure if your question is a control problem. If it is, and the 4DOF mathematical model can be expressed in such form:
x' = f(x) + g(xFc(ω)
where
1. f(x) = [f1(x), f2(x), f3(x), f4(x)]T and g(x) are the nonlinear terms in column vector forms that you derived from the Lagrangian method,
2. Fc(ω) is the control force that represents a function of ω in vector form, and
3. ω (omega) is the control input,
then I think it is possible to design the spin speed profile for the control input, ω, so that the desired responses of x can be achieved. If you want to design the profile, you need to at least understand the mathematical equation for Fc(ω). Do you want to regulate the spin speed at 300 rpm, 600 rpm, or 1200 rpm? Because I see only the signal oscillates within the dimensionless amplitudes ± 4×10–3.
I have plotted the signal according to your suggestion, and compared it with Mahdi's original signal. Note that if t1 > 5/τ, then exp(–τ·θ(t – t1)·t) ≈ 0 after t1, because exp(–0.5·t) has decayed to almost zero.
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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.
Is it possible for you to share your data with me? I have some idea to solve your problem but I need your data.
I'm in touch by : ahmadi.v.1380@gmail.com
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Any references or articles that describe that accurately.
Your work is appreciable as you know it's a quite interesting area. In fact, when I try to explore articles on similar work, I seldom found few articles, which I will share with you, as I hope you may find them beneficial.
Modeling of a hybrid electric heavy duty vehicle to assess energy recovery using a thermoelectric generator - https://www.sciencedirect.com/science/article/abs/pii/S0360544218302512
The Potential of Thermoelectric Generator in Parallel Hybrid Vehicle Applications -
Thermoelectric Generation in Hybrid Electric Vehicles - https://www.mdpi.com/1996-1073/13/14/3742/htm
Modeling of a hybrid electric heavy duty vehicle to assess energy recovery using a thermoelectric generator - https://econpapers.repec.org/article/eeeenergy/v_3a148_3ay_3a2018_3ai_3ac_3ap_3a1046-1059.htm
Holistic Development of Thermoelectric Generators for Automotive Applications -
Best wishes
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Generally observed at low strain rate for fine grained material.
For industrial scale
which are viable materials?
which parameters need to alter?
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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.
The application of jerk in physics have many instances and one of the example I can shot is simple that the jerk is nothing but it is all about the rate at which any objects acceleration changes with the time or with respect to time.
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Kindly express your views what we can decipher from Storage modulus and tan δ.
w.r.t. to failure mechanism, tribological performance etc.
These are great questions!
Storage modulus is related to the amount of elastic structure in the sample and the higher it is, the more solid like the material is (as opposed to liquid like). If the storage modulus exceeds the viscous modulus, the material will usually ultimately fail by breaking elastically rather than being viscously pulled apart. I say usually, as these moduli are determined usually in the linear viscoelastic region (LVR) of the material whereas destructive tests are outside of the LVR of the material.
The ratio of viscous modulus to elastic modulus is also the Tan delta. Therefore if Tan d is below one, the sample is solid-like and if above 1 then liquid-like (although it may be a very stiff liquid).
With regard to tribology, I have less information, however some assumptions may be as follows. If a grease, the elastic modulus would need to be high enough to prevent the material from flowing under it's own weight (and be able to start up flow at all likely environmental temperatures). You may want the viscous modulus to be higher for a system where there are high shear forces eg in a wind turbine (to prevent scratching etc) , whereas it should be lower viscosity (and lower modulus) for a lighter stress application, eg a small motor. People often use a Stribeck curve to mimic an application and measure the friction / lubricity of a surfaces or lubricant.
I hope this helps.
Best regards,
Phil
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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.
Prof. Ajitanshu Vedrtnam: In my opinion, the projects are more than enough instead of your suggested section.
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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?