Latest Discussions - COMSOL Forums Most recent forum discussions Wed, 27 Sep 2023 15:03:55 +0000 COMSOL Forum: Latest Discussions Saving the last iteration of topology optimisation <p>Dear,</p> <p>For my project, I plan to perform an analysis on the final iteration of the topology optimization, where the geometry obtained from this last iteration will serve as the basis for the analysis. How can I do this? Is it possible to save the result of the topology optimisation in a new model and then do analysis?</p> <p>Thank you in advanced!</p> <p>With kind regards, Dehlia</p> Wed, 27 Sep 2023 15:03:55 +0000 4.2023-09-27 15:03:55.330491 Possibility to define Fixed Constraints only for certain degrees of freedom? <p>As part of the topology optimization of a part attached to rods I am looking for ways to restrict only certain DOFs at the mounting points. For example, I would like to restrict the mouvement of the inside surface of a mounting hole only in z direction and not in the other five degrees of freedom. So far I have only found the fixed constraint otpion; however this restricts motion in ALL directions. Does anyone have a clue on how to achieve this?</p> Wed, 27 Sep 2023 11:57:05 +0000 4.2023-09-27 11:57:05.330481 How can I find the change in diameter with time? <p>Hi all, I modelled a 3D model of a pressure tube to find the effect of creep on it.</p> <p>I defined the boundary load, internal pressure, and a creep law.</p> <p>Now I want to find the change in diameter of the pressure tube with time due to creep at a particular location (along length) of the pressure tube.</p> <p>How can I find this. Please suggest me.</p> <p>Thanks</p> Wed, 27 Sep 2023 10:58:36 +0000 4.2023-09-27 10:58:36.330471 How to calculate the power of a terminal in frequency domain study <p>I am following the saw gas sensor example. When try to calculate S parameter, we need to fix the input power of the terminal and then perform a frequency domain study. I try to calculate the power from the terminal current and voltage by the equation for average AC power. But the result are not equal to the value I set to the terminal and it looks similar to the S parameter. Does my calculation give the output power? And How comsol apply the fixed power to the terminal in terms of the boundary conditions ?</p> Wed, 27 Sep 2023 08:47:11 +0000 4.2023-09-27 08:47:11.330461 Rotation angle in rigid connector <p>Hi,</p> <p>In Solid mechanic problem, I made a model using a rigid connector between boundaries (as attached figure). The prescribed angle of rotation to the z axis is set 1 (rad). After the computation, the derived value for the rigid body rotation to the z axis (solid.thz_rig3) is just 0.95885 (rad). Why the values are different and how to have the derived value equal to 1 (rad) as the prescribed value?</p> <p>Thank you!</p> Wed, 27 Sep 2023 07:18:05 +0000 4.2023-09-27 07:18:05.330451 Cut point 3D analysis on applied loads <p>I have done a piezoelectric simulation and have added a Cut Point 3D in geometry. Once i compute the solutions I am able to plot the derived variables result like electric potential on that particular 3D point, but I am unable to graph the applied loads (obtained from initial conditions) to plot applied loads and generated potentials in one single 1D graph. For reference my study is time domain and I am applying a dynamic force over my piezoelectric structure,</p> Wed, 27 Sep 2023 07:16:46 +0000 4.2023-09-27 07:16:46.330442 regarding defining a lower dimension PDE? <p>Is it possible to define a lower dimension pde in a higher dimension using local co-ordinate system?</p> <p>For example in an inclined beam if i want to define a pde in its local cordinate system i.e., co-ordinate system along the length of the beam?</p> Wed, 27 Sep 2023 05:29:00 +0000 4.2023-09-27 05:29:00.330441 Angular momentum <p>Hi all,</p> <p>I'd like to determine the angular momentum of a geometry in a time dependent study in COMSOL. The rotational velocity around the center of mass of the system would also be very interesting, but I haven't found a way to do that either. Has anyone else run into this? Because it feels like this should be really easy to do.</p> Tue, 26 Sep 2023 21:17:17 +0000 4.2023-09-26 21:17:17.330431 gITF with legends <p>Hi Is there a way to include the legend when exporting gITF file for 3D results ? thanks</p> Tue, 26 Sep 2023 17:25:39 +0000 4.2023-09-26 17:25:39.330412 Should I add 0 order when I stimulated diffract grating? <p>Today I stimulated diffract grating through by learning template, if I follow the case ,I can get the same reflect efficiency result picture; However, when I add 0 order under port one , the result changed a lot, so why cause it? and it is need add 0 order or isn't? <img src="http://" alt="" /></p> Tue, 26 Sep 2023 12:51:04 +0000 4.2023-09-26 12:51:04.330393 beam boundary condition <p>How to give displacement boundary condition in an inclined beam with respect to local coordinate system?</p> Tue, 26 Sep 2023 11:25:13 +0000 4.2023-09-26 11:25:13.330391 Gas Diffusion Electrode <p>Hi</p> <p>I'm working on a model for a gas diffusion electrode (GDE) and I'm trying to understand if it's possible to impose an equilibrium condition between gaseous oxygen and liquid oxygen. In particular, I have a balance equation for the gas and one for the liquid species, and I want to impose the exchange equilibrium on the entire volume in the form [O2_liq] = pO2/K*, where [O2_liq] is the concentration, pO2 oxygen partial pressure and K a constant.</p> <p>Does anyone know if it's possible to do this and how?</p> <p>Thank you</p> Tue, 26 Sep 2023 08:40:17 +0000 4.2023-09-26 08:40:17.330362 List of surface to surface radiation operators <p>Hi, I'm looking to compute the view factor for some radiation problems. I see the COMSOL tutorials and blog posts mention the operator <em>radopu</em> and <em>radpd</em>, but I cannot find it in the documentation. Can someone point me the documents that lists these functions.</p> Tue, 26 Sep 2023 06:59:45 +0000 4.2023-09-26 06:59:45.330352 Microwave heating, Magnetic field <p>I was recently doing a simulation of microwave heating, and I wanted to know the temperature changes at different points by adding probes. How can I modify the magnetic field expression of the probe into the formula of temperature change over time that I need?</p> Tue, 26 Sep 2023 01:45:53 +0000 4.2023-09-26 01:45:53.330343 Undefined material property 'Cp' required by mineral oil <p>Hello</p> <p>My colleague and I are having some problem running an immersion cooling simulation. I defined a new material to define material property based off a documentation of novec 7500. However once I run the simulation it gives the above error. The attached is the file.</p> <p>Thank you</p> Mon, 25 Sep 2023 16:40:51 +0000 4.2023-09-25 16:40:51.330342 Wave Optics Module will not Run <p>I am not able to get this model to run and get Warning message “MUMPS is switching to out-of-core mode”. Also get error message: Failed to find solution. Unable to read o write out-of-core file. I have tried different meshing (normal, fine and custom) but no luck in getting it to run. Could it be a meshing issue or something else.</p> <p>Best regards, Richard P.S. Running Windows and COMSOL 6.1</p> Mon, 25 Sep 2023 16:28:58 +0000 4.2023-09-25 16:28:58.330332 Thermal Management of Battery pack <p><img src="http://" alt="" />I have prepared the thermal load on battery pack. I need to understand the cooling strategy calculation using basic physics based knowledge.</p> <p>1 Battery cell voltage 3.6 V</p> <p>2 Battery cell capacity 3000 mAh</p> <p>3 Battery cell energy 10.8 Wh</p> <p>4 Number of battery cells in series 112</p> <p>5 Battery pack voltage 403.2 V</p> <p>6 Number of battery cells in parallel 82</p> <p>7 Number of battery cells 9184</p> <p>8 Battery pack energy 99.1872 kWh</p> <p>9 Mass of battery cell 0.05 kg</p> <p>10 Battery pack energy density 216 kWh/kg</p> <p>11 WLTP Range 195 Wh/km</p> <p>12 Vehicle range 508.6523077 km</p> <p>13 Motor power 60000 W</p> <p>14 Pack Current 148.8095238 A</p> <p>15 Current of a single cell 1.81475029 A</p> <p>16 Resistance of Single Cell 0.00045 Ohm</p> <p>17 Rate of Heat generated per sec in Cell 9.964923469 W</p> <p>18 Rate of Heat generated per sec in Pack 91.51785714 kW</p> Sun, 24 Sep 2023 16:14:15 +0000 4.2023-09-24 16:14:15.330311 Wetting wall boundary condition in LS method together with other boundary condition <p>Hello.</p> <p>I am setting LS method. I want to set a boundary condition on the wetting wall condition simultaniously. However, it is difficult to set additional boundary condition on the wetting wall. Please advice me, thank you.</p> Sun, 24 Sep 2023 11:41:30 +0000 4.2023-09-24 11:41:30.330301 Surface plot in 1D by applying parametric sweeps to 2 variables <p>Hi,</p> <p>I have a 1D model and I have performed a parametric sweeps for xi and u variables.</p> <p>Please how can I integrate a function: Da = xi&#42;sin(theta)&#42;cos(theta)&#42;vx , where, theta and v are the dependent variables which depend on xi and u and x is the independent variables.</p> <p>Then plot contour or surface plot of (xi, u, integral of Da). I have attached the mph file.</p> <p>I would appreciate your help. Thank you.</p> Sat, 23 Sep 2023 22:58:42 +0000 4.2023-09-23 22:58:42.330291 rotational constraint <p>I am trying to do a static analysis of a cantilever beam whose one end is fixed.</p> <p>In the other end I am applying forces axially and also in the transverse direction. But I what this end to be rotationally restraint, but can undergo an axial and transverse deflection. The final deformation of the beam will look somewhat like the attached figure.</p> <p>While I am able to do everything else, i am not able to figure out! how to give a rotational restraint constraint. Someone please help!</p> Sat, 23 Sep 2023 22:30:21 +0000 4.2023-09-23 22:30:21.330281