I have a 3D block of an elastic material. I stretch it from one surface in one direction and for example I stretch it for 5 mm in Y direction. so my input load is either external stretch or external strain( I am not sure which one?). What I can do in COMSOL is that I consider one surface as fixed constraint. But after this step I am not sure which of the following is correct? 1) to consider a boundary load ( if yes how to convert 2mm stretch of the device to the input mode of boundary load?) 2) to consider "External Stress" under linear elastic material? ( if yes how to convert 2mm stretch of the device to the input mode of External Stress?) 3) to consider "External Strain" under linear elastic material? ( if yes how to convert 2mm stretch of the device to the input mode of External Strain?) in this case the input mode can be stretches but what I wonder about is that there is "number 1" next to it that I do not understand what it is
Additionally, my material is an nonlinear elastic. I want to get the resuts in the form of a graph that shows the changes in dimentions of the block along the direction i have stretched the block