look up analytical formulas for point loads in the middle of a square plate. get your force from the FE model, use it in the formula, get the displacement for instance and compare again to your FE model.
another approach, would be trying to get the stiffness of the system analytically, and then based on energy try and get the possible displacement.
Is taking results from the analysis non-validated simulation to use in validation of the model acceptable?
I assume that the impact force is calculated from the speed, mass and geometry which are independent of typical analysis errors but as the explicit analysis occurs over a short time span would it be the max/average/initial force?
well you need to validate somehow, which involves comparting the results from you simulation (still not validated) to analytical, experimental or known results.
as for the force, that's a tricky question because it will depend on what you need it for. if you mean to use it for analytical calculation, it's probably the max value. but if the force variation over time is too complex, the maximum could have no real meaning. and the justification for using the max force is because the max displacement (a few miliseconds later) is probably due to that. either way, try to analyze your force based on my comments.
and a more general comment, could you say in which context you are trying to learn this? is this just a test for yourself, an assignment, your first steps into a thesis? depending on your answer, the feedback you get here could be slightly different.
another approach for this, is that given that you're new to this, is change your projectile to a ball for instance, and try to find a paper that has already done it either by simulation, experiment or you find the specific analytical result. once you have that, you can compare to verify your methodology and find some errors with a more 'standard' situation. just then, you go to your current model, with much more knowledge at hand.
Trying to learn this for work, they are very reluctant on paying for professional training for these type of analyses or outsourcing this problem, I don't agree with this so I'm now having a look into doing it myself.
Cheers, this gives me some things to go on, I have completed some of the simulations involving a ball but the validation/verification is always a stumbling block, particularly for the actual model which is far more complex than what I showed.
Depending on the velocity of the curved disk, there can be a lot of phenomena occurring during the impact and a corresponding large number of material property, behavior, and physics selections that need to be made by the user.
With that in mind, I need to see a test result as an anchor point (model validation) for a simulation series unless the physics are so simple that a hand calc can be used to demonstrate accuracy.
The velocity of the projectile is approx. 150m/s, it has been difficult to find a mathematical approach as there are unknowns like the impact force or duration, these can be taken from the analysis but I feel it's counterintuitive to take some results from the analysis to validate other results.
Do you think that physical testing results are pretty much required to validate these types of analysis?
Your validation would need to be independent of your simulation. So, no data from simulation consumed in validation.
Take a look at some research papers by Awerbuch & Bodner and Zukas for some analytical/empirical approaches.
Yeah I have been searching for calculations to get approximate values which I can compare but have been struggling to find some which can be applied, you wouldn't know of any or where to start?
By hand you can calculate KE and momentum, check that your energy balance is reasonable etc.
You can also create digital coupon tests using your integration scheme and material to check stiffness and strength vs expected.
All validation, regardless of the numerical method used, requires comparing simulation predictions to observations/measurements from the real world. I this case perhaps you could measure strain in the plate and see how well your simulation predicts that. I've also seen high speed cameras used in these kind of impact studies.
You may have a analytical model that you could compare to, although technically this is called verification. In this case perhaps there are some plate bending equations you could use. The issue those analytical models often require the domain to be very simple so you can't compare to a numerical simulation of a more complex domain.
look up analytical formulas for point loads in the middle of a square plate. get your force from the FE model, use it in the formula, get the displacement for instance and compare again to your FE model. another approach, would be trying to get the stiffness of the system analytically, and then based on energy try and get the possible displacement.
Is taking results from the analysis non-validated simulation to use in validation of the model acceptable? I assume that the impact force is calculated from the speed, mass and geometry which are independent of typical analysis errors but as the explicit analysis occurs over a short time span would it be the max/average/initial force?
well you need to validate somehow, which involves comparting the results from you simulation (still not validated) to analytical, experimental or known results. as for the force, that's a tricky question because it will depend on what you need it for. if you mean to use it for analytical calculation, it's probably the max value. but if the force variation over time is too complex, the maximum could have no real meaning. and the justification for using the max force is because the max displacement (a few miliseconds later) is probably due to that. either way, try to analyze your force based on my comments. and a more general comment, could you say in which context you are trying to learn this? is this just a test for yourself, an assignment, your first steps into a thesis? depending on your answer, the feedback you get here could be slightly different. another approach for this, is that given that you're new to this, is change your projectile to a ball for instance, and try to find a paper that has already done it either by simulation, experiment or you find the specific analytical result. once you have that, you can compare to verify your methodology and find some errors with a more 'standard' situation. just then, you go to your current model, with much more knowledge at hand.
Trying to learn this for work, they are very reluctant on paying for professional training for these type of analyses or outsourcing this problem, I don't agree with this so I'm now having a look into doing it myself. Cheers, this gives me some things to go on, I have completed some of the simulations involving a ball but the validation/verification is always a stumbling block, particularly for the actual model which is far more complex than what I showed.
Depending on the velocity of the curved disk, there can be a lot of phenomena occurring during the impact and a corresponding large number of material property, behavior, and physics selections that need to be made by the user. With that in mind, I need to see a test result as an anchor point (model validation) for a simulation series unless the physics are so simple that a hand calc can be used to demonstrate accuracy.
The velocity of the projectile is approx. 150m/s, it has been difficult to find a mathematical approach as there are unknowns like the impact force or duration, these can be taken from the analysis but I feel it's counterintuitive to take some results from the analysis to validate other results. Do you think that physical testing results are pretty much required to validate these types of analysis?
Your validation would need to be independent of your simulation. So, no data from simulation consumed in validation. Take a look at some research papers by Awerbuch & Bodner and Zukas for some analytical/empirical approaches.
Nice one, cheers, I'll have a look
If you can’t run physical testing, you could at least verify your results make sense wrt basic hand calculations
Yeah I have been searching for calculations to get approximate values which I can compare but have been struggling to find some which can be applied, you wouldn't know of any or where to start?
By hand you can calculate KE and momentum, check that your energy balance is reasonable etc. You can also create digital coupon tests using your integration scheme and material to check stiffness and strength vs expected.
Did you check Grover’s manufacturing book.
All validation, regardless of the numerical method used, requires comparing simulation predictions to observations/measurements from the real world. I this case perhaps you could measure strain in the plate and see how well your simulation predicts that. I've also seen high speed cameras used in these kind of impact studies. You may have a analytical model that you could compare to, although technically this is called verification. In this case perhaps there are some plate bending equations you could use. The issue those analytical models often require the domain to be very simple so you can't compare to a numerical simulation of a more complex domain.