how do i input stress strain data for a mat into abaqus from lab tests
how do i input stress strain data for a mat into abaqus from lab tests
(OP)
i have a sheet of plastic tubes that i have done a compression test on and i have the stress strain data that i have converted to true stress and true strain as it says to do in the manuals. it is an elastic plastic and has a typical stress strain curve, how do i put this into abaqus, it is not simply input xy data in as abaqus wants only ascending data , the data i have is not ascending, it has the initial elastic peak then the plstic curve. i ahve youngs modulus and poisson ratio.
i want to be able to do impact tests using a striker on the material with an anvil underneath
any help out there
i want to be able to do impact tests using a striker on the material with an anvil underneath
any help out there





RE: how do i input stress strain data for a mat into abaqus from lab tests
RE: how do i input stress strain data for a mat into abaqus from lab tests
RE: how do i input stress strain data for a mat into abaqus from lab tests
RE: how do i input stress strain data for a mat into abaqus from lab tests
I might be confused from your material data, though. I see an initial point of strain=0.687789991 and stress=0.101316845, the final strain=0.288831924, stress=18.1861244. So is this actually all upside-down? Shouldn't the smallest strain be first, and increment to larger strains? This could be part of the problem since ABAQUS requires the strain be in ascending order. Furthermore, I see in the file you posted, that the 3rd and 4th strain levels are the same, yet have different stress values. ABAQUS has a really hard time with this. You can only have one Y (stress) value for any one given x (strain) level.
Finally, where is the data for everything leading up to the data you posted? I have my excel plot attached here just to make sure we're thinking of it in the same way. (is Stress in Mpa?)
RE: how do i input stress strain data for a mat into abaqus from lab tests
force vs displacement on a 15mm thick piece surface area 89mm
youngs modulus 76mpa poisson 0.3
RE: how do i input stress strain data for a mat into abaqus from lab tests
Having done that, is the region with strain below 0.12 a proper material response or are we just seeing 'settling in' of the test, followed by elastic response? If the latter, I suggest you adjust the stress and strain origins to remove this initial behaviour.
Is the elastic overshoot, followed by softening, then hardening expected behaviour of the plastic? I'm not too familiar with plastics; but I suppose it could be.
In any case, I suggest you follow curlyq's advice and smooth the data. I use Excel and undertake a 'n'-point averaging process, using increasing values of true strain as the independent variable.
RE: how do i input stress strain data for a mat into abaqus from lab tests
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RE: how do i input stress strain data for a mat into abaqus from lab tests
I see it's a compression test. You must take proper account of the sign of the strain (as you do implicitly in cols C and D) and of course the stress. The resulting behaviour presents a different picture for compressive stress versus compressive strain following initial yield.
RE: how do i input stress strain data for a mat into abaqus from lab tests
thanks for your help i will try sorting out the strain now
RE: how do i input stress strain data for a mat into abaqus from lab tests
To mrgoldthorpe - the softening and subsequent hardening of plastic materials (at least in tension) is typical of plastics. The polymer chains initially yield, then realign in the direction of the tension.
I wonder if the stress/strain response you are seeing after your initial yield is an accurate response, however. Also, is this only a singular test? If so you should have more to average the curves. Material properties based off of singular tests are not entirely reliable.
RE: how do i input stress strain data for a mat into abaqus from lab tests
. the material is very consistant
RE: how do i input stress strain data for a mat into abaqus from lab tests
RE: how do i input stress strain data for a mat into abaqus from lab tests
i have an impactor falling onto the anvil with the platic in between