Why so ? The shock load in present video is in the form of time vs acceleration. Eg. when you do testing, you apply time/frequency vs g loads, In FEA we apply loads profile like this.
@Faizal M Their is typo mistakes in graphs,Time vs acceleration profile. It should be acceleration Vs time and same is mentioned in the video description.
In our training they always suggest us to use base excitation so that it will resemble real case testing. But in your above case you have applied acceleration directly, which is confusing me. Because always the shock is applied through base and if it's not through base it is that you are moving your body with the applied acceleration in air which won't include realistic experience of shock. Can you please give the detailed explanation if possible?
You are right if you are resembling with testing, you can keep yes for base excitation and apply in respective directions. In some cases, testing not physible so based on global loads criteria, loads can be applied globaly.
Welcome ! Damping varies with the equipment and we consider to consider the uncertainty in the FEA Model. Better to keep below 5 %. We will try to create separate video for regarding damping.
@@graspengineering9249 i m doing pressure shock load analysis (peak pressure = 510 MPa at 23millisecond). The equivalent stress i m getting is 2266 MPa in some localised region, while the yield stress of material is 850 Mpa. Dothese localised region have stress singularity and so shall i ignore these high stess region?
@@rango1437 Hello Imran, You first need to check whether the stresses are localized or realistic. The other way to check do the static analysis with the peak (load) pressure application and check the stresses at that region. If you found stresses are localize then you can ignore the stresses.
@@graspengineering9249 i have already done the static analysis to check if my stesses which are coming too high in case of transient analysis approximately match with the static analysis result...With static analysis taking peak pressure (510 MPa) as load, i m getting Max Equivlent Von-mises stess as 2105 MPa at the same location..Does that mean it is a localised stess?? (as these high stresses appear as a red line with a very small thickness, rest all over the part stresses are well below yield point of 850 MPa )..pls comment
Hello Sir, First of all thank you very much for the video, it is very useful. I would like to ask you a question, is it possible to do this example applying the base acceleration instead of applying the acceleration directly? I tell you that because i am not able to do it, for a transient analysis, with no modal. When it comes to select the boundary condicitions in the applied acceleration, the software do not let me select the boundary coinditions, It is as if the software does not recognize it..... There is any option to apply base acceleration for non-linear? Please keep doing videos like this. Many thanks. Regards from Spain!
If you apply Base acceleration as a function of gravity, it should be sufficient if your analysis is mass-based. This is how most software packages like Autopipe or STAAD do it. Industry hasnt shown any concern with this method. At the end of the day, for your FEA to solve you need to make sure it's constrained somewhere.
How extraction of frequency is helping in displaying stresses over time. What i mean is how can the transient structural analysis knows at which frequency it will shows maximum stress. Also how frequency domain input is helping in calculating time domain output?
Hello ! for transient structural analysis, frequency vs accn is loads for which we will get the stresses. Based on the load path on the geometry (over period of time) is depicts the stresses. e.g. When you are doing testing, you are applying external loads or load profile on (shaker table) for that you will get the response (failure if any). FEA also does the same.
Thank you, sir, for your instructive videos. How can I extract the acceleration time history of the response of my structure for different location of it?
What if I don't have load table. I just have an impact load and time for which it acts. How should I apply it? Is it ok if I apply the impact load at exactly half of the time for which it acts?
You can also do static impact analysis. Apply impact loads at small portion of the object and check the stresses, Or else you can assume times before and after impact and do the transient simulation.
thank you for your good video . can i use this transient structural method to obtain volume loss for operating bearing wear that caused by load, pressure and friction ? thank you for your explanation and opinion
Thak you for your video, I would like to know that, how can apply the velocity instead of acceleration? you have talk little about that on your video (13:30) but i couldn't understand not much cos of english.
Can you please explain how to setup a model in which assembly under gose on shaker bed for certain hrs with 15Hz and 2g load and sleepage happening in assembly?
Shaker beds behaves as random vibration. You can perform modal plus random vibration and define loads as frequency vs G acceleration. (0 to 15 hZ & 2g load profile).
Thank you for appriciation. I have taken random assumptions based on experience. At actual, you will have similar shock loading input, it's varries based on shock eg. Wether it is due to pot holes while transportation or any machine shock or any Montreal shock profile. Also you might get this profile from few transportation standards based on country.
In the same problem, why acceleration due to gravity was not applied?? For modal I can understand, but for transient why acceleration due to gravity was not applied for the problem?
Hello Krishna, For present case, the model analysis is the initial condition which will gives the mode shapes including structure gravity effects. Also the loads applied are acceleration loads hence not needed. If suppose you will apply gravity and acceleration loads too, the effect will be double.
in the structure the deformation is very much less but in the image it is showing very distorted structure how the image can be taken in without distorted structure
In case of base excitation loads will be applied through base only. While in other case for all bodies and will transfer to the centroid. Base excitation is useful when we have testing data which is generally measured at the base location like supports.
Sir i was analysing a str. With time and acceleration data in transient but it was not showing base excitation option to define boundary conitions... Plz help me how to define this boundary condition. I want to apply acceleration to base. I defined base as a fixed property in Modal ,but after inputting time acceleration data it is showing direction of acceleration in C.g (centre of gravity) of body. But i want to apply acceleration only in base . Help me to figure this problem
Actually sir that was the main problem. I was finding this option in detail box... But there was no option for base excitation.. i am using version 15 . Is it the problem of ansys version..??
Sometime lower ANSYS version don't have direct load application. Please share few snapshots. In 15.0 also you will find option, try with full method approach without model analysis too.
Actually sir i checked this problem in version 19, i found option for base excitation , but in version 15 i did not found , in main workstation server ansys version 15 is installed , so can you tell me some steps to find base excitation option in version 15
How can I make Acceleration VS Time graph for 20g 11ms, could you please help me out- how to create half-sine pulse graph- ACCELERATION SHOCK RESPONSE SPECTRUM 20G, 11 msec HALF-SINE SHOCK
Very good question, I am facing the same problem that how 30g is calculated and how to put value into transient analysis for 15 ms half sine shock and 10 shocks.
sir i am analysing a structure for which i have to input a Time history having a 30sec duration . When i am inputing the TH it takes so much time , and analysis even not completing. Is there any other way to input the TH. ?
In FEA non-linearity can be defined by three things 1.Geometric non linearity (geometry shape will change abruptly, Spring, Rubber seal boot) 2. Material non linearity and 3. Contact non-linearity Here material stiffness is changing for load application, stress vs strain curve is nonlinear. While in case on linearity, material is linear , stress vs strain curve is linear. We are working on video for more explanation on linearity and non linearity.
We have not uploaded any video for wood material yet. You might need to model the model wood as composite material or use wood material from ansys material library, apply loads and boundary condition and find out stress and creep phenomenon. Will upload video on creep phenomenon soon.
very well explained, it is very usefull for me. Thank you
I noticed that in your shock loading figure, the X axis should show Time and Y axis should show ACCELERATION.
Why so ? The shock load in present video is in the form of time vs acceleration. Eg. when you do testing, you apply time/frequency vs g loads, In FEA we apply loads profile like this.
@@graspengineering9249 Thats what @madhav kale is trying to explain, u have taken X-axis as Acceleration and Y-axis as Time instead of vice versa
@Faizal M Their is typo mistakes in graphs,Time vs acceleration profile. It should be acceleration Vs time and same is mentioned in the video description.
Great demo, very useful
Glad it was helpful!
In our training they always suggest us to use base excitation so that it will resemble real case testing. But in your above case you have applied acceleration directly, which is confusing me. Because always the shock is applied through base and if it's not through base it is that you are moving your body with the applied acceleration in air which won't include realistic experience of shock. Can you please give the detailed explanation if possible?
You are right if you are resembling with testing, you can keep yes for base excitation and apply in respective directions. In some cases, testing not physible so based on global loads criteria, loads can be applied globaly.
Thanks for sharing this. Great video. Could you advice also how you decide for the damping coefficient? I think you input some value like %2?
Welcome ! Damping varies with the equipment and we consider to consider the uncertainty in the FEA Model. Better to keep below 5 %. We will try to create separate video for regarding damping.
very well explained..can u also explain how to get fatigue life of shock loaded structure here.
We will upload the video on same. You can do for fatigue peak and valley condition and Use Ncode software or hand calculations for fatigue analysis.
@@graspengineering9249 i m doing pressure shock load analysis (peak pressure = 510 MPa at 23millisecond). The equivalent stress i m getting is 2266 MPa in some localised region, while the yield stress of material is 850 Mpa. Dothese localised region have stress singularity and so shall i ignore these high stess region?
@@rango1437 Hello Imran, You first need to check whether the stresses are localized or realistic. The other way to check do the static analysis with the peak (load) pressure application and check the stresses at that region.
If you found stresses are localize then you can ignore the stresses.
@@graspengineering9249 i have already done the static analysis to check if my stesses which are coming too high in case of transient analysis approximately match with the static analysis result...With static analysis taking peak pressure (510 MPa) as load, i m getting Max Equivlent Von-mises stess as 2105 MPa at the same location..Does that mean it is a localised stess?? (as these high stresses appear as a red line with a very small thickness, rest all over the part stresses are well below yield point of 850 MPa )..pls comment
Hello Sir,
First of all thank you very much for the video, it is very useful. I would like to ask you a question, is it possible to do this example applying the base acceleration instead of applying the acceleration directly? I tell you that because i am not able to do it, for a transient analysis, with no modal. When it comes to select the boundary condicitions in the applied acceleration, the software do not let me select the boundary coinditions, It is as if the software does not recognize it..... There is any option to apply base acceleration for non-linear?
Please keep doing videos like this.
Many thanks.
Regards from Spain!
thank you
If you apply Base acceleration as a function of gravity, it should be sufficient if your analysis is mass-based. This is how most software packages like Autopipe or STAAD do it. Industry hasnt shown any concern with this method. At the end of the day, for your FEA to solve you need to make sure it's constrained somewhere.
How extraction of frequency is helping in displaying stresses over time. What i mean is how can the transient structural analysis knows at which frequency it will shows maximum stress. Also how frequency domain input is helping in calculating time domain output?
Hello ! for transient structural analysis, frequency vs accn is loads for which we will get the stresses. Based on the load path on the geometry (over period of time) is depicts the stresses. e.g. When you are doing testing, you are applying external loads or load profile on (shaker table) for that you will get the response (failure if any). FEA also does the same.
I too had this same doubt...Still I do not understand why modal analysis is done prior to transient.
Thank you, sir, for your instructive videos.
How can I extract the acceleration time history of the response of my structure for different location of it?
Hello, You might need to do testing and put accelerometers at various locations on structure like base, excitation points, etc.
What if I don't have load table. I just have an impact load and time for which it acts. How should I apply it? Is it ok if I apply the impact load at exactly half of the time for which it acts?
You can also do static impact analysis. Apply impact loads at small portion of the object and check the stresses, Or else you can assume times before and after impact and do the transient simulation.
Great experience
thanks.
Where can I find this model for practice?
Well explained
Thank you for appreciation !
thank you for your good video .
can i use this transient structural method to obtain volume loss for operating bearing wear that caused by load, pressure and friction ?
thank you for your explanation and opinion
Yes, But you should load vs time profile for the same.
@@graspengineering9249 where to put load vs time profile . can you show the video at what minutes ?
This was very helpful , thanks
Thank you !
Thanks for sharing this. Can I get the sample project file and PPT of this talk
Welcome ! You can use video and try to replicate the same. We do not have ppt copy.
Thak you for your video,
I would like to know that, how can apply the velocity instead of acceleration? you have talk little about that on your video (13:30) but i couldn't understand not much cos of english.
why you want to apply velocity. We should simulate the actual scenario.
Can you please explain how to setup a model in which assembly under gose on shaker bed for certain hrs with 15Hz and 2g load and sleepage happening in assembly?
Shaker beds behaves as random vibration. You can perform modal plus random vibration and define loads as frequency vs G acceleration. (0 to 15 hZ & 2g load profile).
Hey sir
How do you make the point in space that is connected with red lines
Hello ! It is remote point on which you need to apply point mass.
Good work sir.
Thank you for appriciation!
Really good work, just like to ask how you decide upon the data for acceleration input ( I mean the input values) for your transient analysis? TIA
Thank you for appriciation.
I have taken random assumptions based on experience.
At actual, you will have similar shock loading input, it's varries based on shock eg. Wether it is due to pot holes while transportation or any machine shock or any Montreal shock profile. Also you might get this profile from few transportation standards based on country.
Sir can we apply fatigue tool after transient analysis to calculate vibration fatigue stress?
Yes. you can consider.
how i create the time and acceleration excel .Is there any formula is there??
It is vibration profile. You will get acceleration vs frequency data from measurement through accelerometer.
What is the full method analysis can u make a video on that
Okay.
Why background music requires.. for this useful video
We started removing for latest video.
In the same problem, why acceleration due to gravity was not applied?? For modal I can understand, but for transient why acceleration due to gravity was not applied for the problem?
Hello Krishna, For present case, the model analysis is the initial condition which will gives the mode shapes including structure gravity effects. Also the loads applied are acceleration loads hence not needed. If suppose you will apply gravity and acceleration loads too, the effect will be double.
in the structure the deformation is very much less but in the image it is showing very distorted structure how the image can be taken in without distorted structure
You can increase the scale in results section for deformation or stress plots
Why u didn't turned on the base excitation ?
If so then there is no point in performimg MSUP...
In case of base excitation loads will be applied through base only. While in other case for all bodies and will transfer to the centroid. Base excitation is useful when we have testing data which is generally measured at the base location like supports.
What about "function" does it include half sine wave function....?
Yes !
Sir i was analysing a str. With time and acceleration data in transient but it was not showing base excitation option to define boundary conitions... Plz help me how to define this boundary condition. I want to apply acceleration to base. I defined base as a fixed property in Modal ,but after inputting time acceleration data it is showing direction of acceleration in C.g (centre of gravity) of body. But i want to apply acceleration only in base . Help me to figure this problem
You will find in details, Base excitation. Make is Yes. Then u can apply
Actually sir that was the main problem. I was finding this option in detail box... But there was no option for base excitation.. i am using version 15 . Is it the problem of ansys version..??
Sometime lower ANSYS version don't have direct load application. Please share few snapshots. In 15.0 also you will find option, try with full method approach without model analysis too.
Actually sir i checked this problem in version 19, i found option for base excitation , but in version 15 i did not found , in main workstation server ansys version 15 is installed , so can you tell me some steps to find base excitation option in version 15
How can I make Acceleration VS Time graph for 20g 11ms, could you please help me out- how to create half-sine pulse graph- ACCELERATION SHOCK RESPONSE SPECTRUM
20G, 11 msec HALF-SINE SHOCK
We will create separate video on this.
Very good question, I am facing the same problem that how 30g is calculated and how to put value into transient analysis for 15 ms half sine shock and 10 shocks.
@@graspengineering9249 Pls make a video on this
Can I use cyclic symmetry in transient analysis?
Better to avoid, as loads are not symmetric.
sir i am analysing a structure for which i have to input a Time history having a 30sec duration . When i am inputing the TH it takes so much time , and analysis even not completing. Is there any other way to input the TH. ?
Kindly check the mesh count and loading profile properly. If you have ll the correct details, you will able to solve.
Sir what is non linearity and linearity
In FEA non-linearity can be defined by three things 1.Geometric non linearity (geometry shape will change abruptly, Spring, Rubber seal boot) 2. Material non linearity and 3. Contact non-linearity
Here material stiffness is changing for load application, stress vs strain curve is nonlinear.
While in case on linearity, material is linear , stress vs strain curve is linear.
We are working on video for more explanation on linearity and non linearity.
Thank you sir ! Beautiful explanation 😍😍
Como podria estudiar Creep en muestras de madera
We have not uploaded any video for wood material yet. You might need to model the model wood as composite material or use wood material from ansys material library, apply loads and boundary condition and find out stress and creep phenomenon. Will upload video on creep phenomenon soon.
thanks you very much
Please Run the translation in your videos
Okay We will do.
voice is very low...have to press earphone hard to hear voice over music...remove music it's useless in these kinds of edcational video
Hello, This video is older. Will try to upload further. Please refer new videos for sound clarity.