Mass scaling is a way of reducing the computational cost of analysis. I read it on tutorials, I learnt that mass scaling effects the critical time increment. I couldn't find any source about how It can reduce the computational cost.
We can also increase the load rate, in order to reduce the computational cost, but if material is rate-dependent, load rate effects the results. Does the mass scaling have negative effects like load rate?
If you can suggest me any source which explain the reducing the computational cost process and If you can explain possible negative effects of mass scaling, I will be appreciated to you.
read the Abaqus Documentation- Abaqus Analysis User's Manual- Section 6.3.3 -Explicit dynamic analysis.
The time increment in an explicit analysis is calculated from an characteristic dimension of the smallest element and the wave speed. Sometimes ist possible to scale the mass of some small elements without altering the results- there is the total change of mass reported in the status file and if that is less than e.g. 1 percent and the smallest elements are not in critical regions you should be fine!
read the Abaqus Documentation- Abaqus Analysis User's Manual- Section 6.3.3 -Explicit dynamic analysis.
The time increment in an explicit analysis is calculated from an characteristic dimension of the smallest element and the wave speed. Sometimes ist possible to scale the mass of some small elements without altering the results- there is the total change of mass reported in the status file and if that is less than e.g. 1 percent and the smallest elements are not in critical regions you should be fine!
Thanks for your interest about my question. Your explanation was very useful for me. I understood the mass scaling process well.
Hi, actually a quasi-static simulation means that there is no strain rate effect and no inertial effect on the part that you simulated. Strain rate part is OK, you can give quasi-static material properties of your material, but for inertial part you need to take additional care. In mass scaling then you have to increase (or decrease) density of the material of the part and then you can increase the rate of simulation without any inertial effect. Then you obtain a quasi-static loading scenario with low computational cost. But you have to check the kinetic energy/total energy and this must be less than 4% for example to assure quasi-static rates.
You can find details in "Experimental and numerical studies of foam-filled sections" by Santosa et al., International Journal of Impact Engineering, 24(5), 2000, pp. 509-534.
Sincerely.
Ali, thanks for your interest and suggestion. This paper will be helpful for me.
Hi all, I have an explicit dynamic model and want to build the static one using the same model. So can I perform quasi static analysis for the same model using dynamic explicit? how?. Also, if I replace the explicit step by general static, what things I have to change?
Thanks..
Read this blog,
https://caeai.com/blog/what-mass-scaling-and-when-it-appropriate-explicit-dynamics-analysis
As ABAQUS User Manual suggested, the mass scaling is only applied to the elements that are critical in determining the computational time. These regions usually are meshed to smaller sizes because they are the critical regions. Then isn't that the mass scaling will have an impact on the regions that we are interested in?
Hi all,
I can see that ensuring quasi-static manner means that the kinetic/total energy ratio must be very small, but does that mean that the mass increase is then not interesting anymore? During e.g. an uniaxial extension is it no problem if the mass increase is more than e.g. 5000% if this energy ratio is insignificantly small? I am interested in the reaction force of course during these simulations.
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