Running model made in comsol 5.1 in 5.2a

#RUNNING MODEL MADE IN COMSOL 5.1 IN 5.2A HOW TO#

Then I play with my formulas until I'm happy, jsut to copy and paste them into the right field somewhere else usually in boundary conditions GUI fields.Д¬lear you can define a GLOBAL scalar expression rho_ratio=mat1_rho/mat2_rho but this is a sort of constant (note you cannot define it as a 'CONSTANT' because the 'mat1.' are not defined yet when the Constants are evaluated, (these are evaluated only once at the beginning of a run for 3.5a, parameters seem to be slightly different in V4 TBC) One trick, when I need to check formulas, I usually get the initial values (to populate all matrices with initial values and check model coherence) then I use the postprocessing Point evaluation of any point. OK, I expeceted that you wanted something trickier, but I wasnt really shure M file to get most of the names explicitly out. I forgot to say that all variables are not shown in the physics _equeation settings, you must turn on the 'Options preferences modelling tab, Include default values'. Note: in V4 the names have change and its rather '' or just 'solid.rho' that should be used (the translation of mat1 I do not know, would have to look up the internal equations see preferences in V4) if you have only one material let's say mat1 you could use mat1.rho to get the same results, but if you have several materials, the mat1.rho would force the calculation to use only the density of mat1 and not the specific material indexing you had specified (assuming you have several metarials) You select all domains and type in 'rho_smsld' as the volume integrand, this will give you the integration of rho time dV=dxdydz or in fact the total mass. Then you do a 'Solver - Get initial values' (in 3.5) and you select the Postprocessing Geoemtric properties, or Domain integration (the latter is probably more explicite: Again in structural (because it's my fisrt though, but it applies to most/all material variables by analogy): choose 3D smsld, if you want to define the total mass or inertia, you define your model set up the geometry the materials and the boundary subdomain definitions. it might not give you the right result.ДЄnother example to try to illustrate this. while if you use the variable 'mat1.rho' it referes always to a specific material, regardless what domain is active when the formula is used. This formuly is correct even if you change the material type to let's say mat2 sometiomes later in your model history. When you fill ina formula in the GUI you normally have defined a domin to which it applies (ir it is implicit by inheritage, so you can use the physics variable name 'rho_smsld' to refer to the density.

Then when you asign a material to a domain, COMSOL fills in the 'rho_smsld' internal variable of the current application mode the 'smsld' physics. When you import a material, COMSOL assigns it a name of the type mat1 mat2 and adds the suffic of the variable, the 1,2,3 are the order in which you defined the material, not important only to make them unique. So I would suggest strongly debug a model with fixed material data, then introduce non-linearities one by one in a controlled way. This has been enhanced in V4 by 'Red Stop marks' but still I have managed to get reasonnable (but wrong) results by forgetting to check all my material data, and the solver whent through OK ! I normally do not refere directly to the material name 'mat1_rho' but to the comsol material name 'rho_smsld', in V3.5a or 'solid.rho' in V4.Д«y this COMSOL looks after the reference to the correct frequency, temperature or pressure, and to select the different material rho values depending on the group selection I have active on the subdomains.Д¬lear, what one often forget in V3.5 is that selecting a database complex non-linear function material one is forcing non-linear solvers (longer to solve) and that there are often'hidden' parameters such as ambient temperatuure Tempref or pressure 'p' that needs to be defined. I would very much appreciate any suggestions on this. This happens even when I have an expression equal to just a single material parameter so that there cannot be any inconsistency with the units. How would I for example refer to the density of air in an expression? All my attempts just result in the error/warning 'Inconsistent unit'.

#RUNNING MODEL MADE IN COMSOL 5.1 IN 5.2A HOW TO#

My simple problem is that I don't know how to refer to a specific material parameter. I would like to use the materials properties in global expressions in my simulations. I am using Comsol version 3.5a through the GUI. I didn't quite understand your explanation.

Running model made in comsol 5.1 in 5.2a