Mechanical Engineering - Science topic

yes

The Thomson anisotropy parameter is a measure of the degree of anisotropy in a material. It is defined as the ratio of the difference between the elastic constants to their sum. For an orthotropic material, the Thomson anisotropy parameter can be expressed as:

𝜂=𝐶11-C33C11+C33

where C11 and C33 are the elastic constants in the principal material directions.

The elasticity matrix for an orthotropic material can be derived from the phase velocities of the material. The phase velocities are related to the elastic constants and the density of the material. The phase velocities in the principal material directions can be expressed as:

𝑣1=C11ρ𝑣3=C33ρ

where v1 and v3 are the phase velocities in the principal material directions, and ρ is the density of the material.

The Thomson anisotropy parameter can be used to derive the elasticity matrix by substituting the expressions for the phase velocities into the expression for the Thomson anisotropy parameter. This gives:

𝜂=𝑣12-v32v12+v32

This equation can be solved for the elastic constants C11 and C33, which can then be used to derive the elasticity matrix.

In discussions regarding the appropriate Capillary Number (Ca) for ignoring capillary effects in microchannel studies, it's essential to consider the context of the interface interactions. Typically, for water flow inside silicone microchannels, many studies, including mine, use the water-air surface tension value of 0.0726 N/m. This is generally because the dominant interface under investigation is between the water and air, not between the water and the silicone walls, unless specific surface modifications of the silicone suggest otherwise.

Furthermore, concerning the critical value of Ca, while the standard threshold is often set at Ca = 1, I believe this may not be universally applicable. In my study, which investigates forced flow with Reynolds numbers between 125 and 1300, it appears that capillary effects could be non-negligible even above this threshold. This observation leads me to suggest that the traditional threshold of Ca = 1 might need adjustment based on specific experimental conditions and flow behaviors. Such an approach allows for a more nuanced understanding of when viscous forces indeed dominate over capillary forces in practical scenarios

Farshid Hesami

see the upper plateu gives sigma sas and sigma fas and lower plateus gives you values of sigma s sa and sigma fsa i did this in ansys. dont know which simulation software u use

Sina,

I've focused on this before, but I haven't found a threshold value of force to describe intima damage. I saw a master's thesis describing 1-2 MPa can cause intima damage, but its citation is not credible. So I won't recommend it.

But this article will hopefully help you out a little bit.

The first option is more appropriate.

Run the following in your CMD => C:\whatever directory you're in>abaqus cae recover="C:\temp\name of your file.jnl". It may ask about inconsistencies and whether it should carry on, answer "yes to all" if it does.

Engr. Tufail I have a similar question，the Abaqus.dat file mentioned “ERROR: SIM database file cannot be opened - System Error CreateFile: code1023 ”

How could I solve the error？

Kind regards

Andy

Dear Raheem:

I pay taxes in Canada.

No worries. I'll attempt to publish via Nuclear and Welding in the near future.

Sincerely

Paul Cheng

Enclose crystalline structure of what we are doing. Fine grained base to base. No HAZ.

Tobias Makuochukwu Onyia Thanks a lot!

University of Cologne Germany.

Theoretically, it doesn't matter whether the specimen is rectangular or circular, But technically a problem may arise with circular specimens if you use knife edges on your transverse extensometer. The knives may bite into the specimen by an unpredictable depth, depending on radius. On flat surfaces their clamping force is distributed. It is not a coincidence that testing standards like ASTM E132 advise to use rectangular cross-section for measuring Poisson's ratio.

Also, it is beneficial to have specimens as wide as possible to increase gauge length of transverse measurement. At the same time it is not wise to increase greatly the overal cross-section, because that may require buying a new, testing machnie with bigger force limit ). Rectangular shape allows to vary with and thickness independently.

Computing the displacement at failure which serves as input for the damage evolution is definitely something that it is not trivial and it depends on, as always, on some assumptions that you make.

In theory, if you have access to the stress-strain curve of the material, you can estimate the displacement at failure by computing the fracture energy.

Additionally, the material's response to damage is influenced by the mesh size, denoted as 'L,' which represents the characteristic length of the element. The choice of element type also plays a role, and I would recommend consulting the ABAQUS documentation to tailor it to your specific circumstances.

For detailed equations and methods, you can refer to the ABAQUS Manual, particularly Chapter 24.2.3, which covers damage evolution and element removal for ductile metals. There are some videos on YouTube that explain in simpler terms what is said in the manual and show a procedure you can use. Below you can find them:

[1] Tutorial: How to calculate fracture energy for damage evolution for damage for ductile metals?

[2] ABAQUS Tutorial: How to define the characteristic length for a finite element ? and its application

Hope that helps with your question!

References:

Damage evolution and element removal for ductile metals - ABAQUS Manual http://130.149.89.49:2080/v6.13/book/usb/default.htm?startat=pt05ch24s02abm43.html

Abhishek Chawan

You can check for the mass vs time plot. consider the initial and final mass to get to know about the eroded mass during the simulation.

Merry Christmas to All Colleagues and Hope for Better Tomorrows for Humanity. Thoughts and compassion for the innocent victims of armed conflicts in Ukraine Palestine and everywhere else.

Open letter from the Palestinian Patriarch "from https://groupegaullistesceaux.fr/ (Own Translation from French)": Michel Sabbah, the former Latin Patriarch of Jerusalem, addressed the global public from the birthplace of Christ in Beit Lahm, through the "Palestine 100 Initiative" platform, for this year's Christmas. In a message dedicated to war-fallen Gaza, the Patriarch said, "Christmas this year, in Beit Lahm and all over the world, is a prayer to God Almighty, to stop the war in Gaza and all of Palestine. During these days, many direct their eyes and hearts to Beit Lahm, but only an hour away, they see the war in Gaza, where humans are buried beneath the rubble of their own homes, they see children beneath the rubble, they see humanity beneath the rubble."

This response is meant to assist anyone who might encounter a similar issue in the future. When dealing with welding or laser cladding in additive manufacturing, it's crucial to inspect the interaction between two distinct components. When simulating Welding/Additive manufacturing, there need to be two separate parts (substrate and clads). The mesh generator creates separate meshes for each part leading to un-overlapped nodes in contact areas. FEM solves the equations within all nodes. The un-overlapped nodes on contact areas cause these negative values (which are not seen in the contours).

Yes! Thanks!

Thank you so much dear Prem Baboo

The microfluidic method might be helpful. Please see the paper titled " Novel in-capsule synthesis of metal–organic framework for innovative carbon dioxide capture system".

Thank you Abdulsalam Abdu

You are welcome Aynaz Biuky

Thanks dear Prem Baboo

To estimate fluid velocity in a heat exchanger without knowing the surface area, you can make assumptions and employ simplified methods. Assuming a known heat transfer rate (Q) and overall heat transfer coefficient (U), rearrange the heat exchanger equation to solve for surface area (A). Although the surface area cannot be directly determined without more information, you can estimate fluid velocity by assuming a velocity profile, using the cross-sectional area of the exchanger, or relying on known inlet or outlet velocities. These approaches involve simplifications and assumptions about fluid behavior within the exchanger, emphasizing the need for detailed design specifications or manufacturer information for more accurate calculations.

In the H2-O2 combustion system, the HO2 radical plays several significant roles:

Dear Prem Baboo isn't this equation for pure substances?

The most common approach to variation of Cp is a polynomial fit (keep the order low, not more than cubic), or for small ranges a simple linear fit is commonly used. Remember that extrapolation is always risky with curve fits. There are more complicated equations of state that are used in high precision work and extrapolate better, but these are rarely needed in practical problems.

The following formula can be performed to calculate an ellipse's polar moment of inertia, sometimes recognized as the polar second moment of area:

I_p​=1/4*​πa³b

Where:

· I_p​ is the polar moment of inertia.

· a is the semi-major axis of the ellipse.

· b is the semi-minor axis of the ellipse.

I think you can try something like this

Temperature sensors may struggle to accurately detect the temperature of gases due to issues such as insufficient thermal contact, low thermal mass of gases, sensor compatibility challenges, variations in heat transfer rates based on gas properties, and potential calibration and sensor limitations. To precisely measure gas temperature, it's crucial to select the appropriate sensor type and consider the specific gas properties and application conditions, which may require specialized sensors or techniques like infrared thermometers or thermocouples.

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.

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.

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:

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.

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?

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.

specific changes that you can make to your dynamic mesh settings:

While increasing load on the engine brake power increases more than the fuel consumption so bsfc decreases

You can use the sin function.

if(sinwt>0,source,0). (please recheck the syntax of the if function).

What software do you want to solve the problem? Fluent? CFX?...?

Alexxandra Jane Ty Elmira Ghazanfari Jajin Aleksandar Maksimović Nelaturi V Raghavaiah

The following article regarding apple cultivars are relevant to this case:

And why sparse matrix has computational benefits than diagonal matrix for large sizes ?

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.

Kika VI

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!

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?

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:

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.

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.

You may want to check my post elsewhere at this forum ― as a case study related to transient mass balance analysis:

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.

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.

Yes, you have to define a multi-phase model, e.g., VOF or Euler-Euler.

Origin is better for Pro

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

Milon Selvam Dennison

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:

Cons of MQL include:

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.

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.

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 .

Veeraraghavan Pandurangan

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

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

To define debonding at the matrix-particle interface using the cohesive surface method in Abaqus, you can follow these steps:

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.

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:

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...

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.

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?

Thanks in advance!

National University of Malaysia

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

Hi,

You may be interested in our new article on modeling FGM in ANSYS APDL.

please take a look through its DOI link:

We are eager to have your feedback.

best regards.

Ahmed Hassan Ahmed Hassan

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.

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 :

choose the set of data at E-Ef closest to zero.

I hope to find the answer in the following pdf

Dear

Thank you for your answer. I think mixing energy cost (MEC) is the index that I look for it.

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?

I think this article may be helpful