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Hello, I have been trying to assign a local coordinate system to a group of constraints and my model so that I can load it in a direction specified by the local coordinate system. Therefore, I believe I need to use the Mesh>Assign>Node Analysis System and BCs>Assign>Load Reference System for all my constraints and model nodes. However, when trying to assign the Node Analysis System, only "set displacement" works. "set reference" gives an error saying that "Nodes defining a system cannot be assigned to it". I have a feeling this is why my Optistruct simulation is quite bad. Interestingly, I tried the same method on a very simple box model in a separate model, and created a coordinate system using the nodes of the box. I was able to "Set reference" without a problem, and I could see a clear change in the OptiStruct displacements to the new local coordinate system. I am wondering why my other model does not allow me to set the reference. Any advice is very appreciated.
Hello guys, I'm currently trying to simulate a 3 point bending test to get the best material arrangement for high bending stiffness in a composite monocoque, while keeping the weight low. The laminate i strive for is a sandwich structure with an aramide honeycomb core in the centre and three plies of different material on top and on the bottom. These are the steps I did so far: 1) I created a CAD model, imported it to HyperMesh, organized the componets (specimen, impactor, support) and meshed them with 2D elements. 2) I created the materials. MAT1 for the impactor and the support of the 3 point bending test, MAT8 for the different plies and MAT9ORT for the honeycomb core. 3) After that I created the properties. PSHELL with an elementthickness of 2 for the impactor and support, PCOMPP for the plies and PSOLID with the honeycomb material for the core. 4) Then I created the different plies. 6 with the MAT8 material for the top and bottom layers and 5 with the MAT9ORT material for the core to get a total of 5 elements over the thickness of the core. The material type for all plies is ORTHOTROPIC. 5.1) I created a laminate with the 5 core plies and then did a "shell to solid conversion" with this laminate. After that I got a new component with 5 elements over the thickness. [5.2) In a second try I did the "shell to solid conversion" with the plies of the core which led to the same result as 5.1] 6) I assigned the PCOMPP property to the specimen elements, otherwise the laminate and layers weren't visible over 2D detailed element representation. 7) I updated the laminate with the other 6 plies. 8) Finally I created the load collectors and the load step, an output request for CSTRAIN and CSTRESS 9) I started OptiStruct to run the analysis. But after a few seconds i got these errors: *** ERROR 14: Missing MAT # 5 referenced by PLY # 7, (existing MAT with this ID is of incorrect type). *** ERROR 14: Missing MAT # 5 referenced by PLY # 8, (existing MAT with this ID is of incorrect type). *** ERROR 14: Missing MAT # 5 referenced by PLY # 9, (existing MAT with this ID is of incorrect type). *** ERROR 14: Missing MAT # 5 referenced by PLY # 10, (existing MAT with this ID is of incorrect type). *** ERROR 14: Missing MAT # 5 referenced by PLY # 11, (existing MAT with this ID is of incorrect type). *** Errors with missing, incorrect or duplicate IDs found 5 times. So when I got back to the model to check the properties, I wasn't sure if the PSOLID property and the MAT9ORT material are assigned to the plies in the laminate or to the new created component for the solids of the conversion. I want to get a laminate with from top to bottom: 3 layers of PCOMPP MAT8, the PSOLID MAT9ORT core and then 3 layers of PCOMPP MAT8 again. Is it even possible to creat such a laminate and if yes, in wich order should I assign the properties and creat the laminate?Or are there other ways to simulate this kind of sandwich structure in HyperMesh and OptiStruct? Here I uploaded the HM file so you can have a detailed look at my model: http://www.file-upload.net/download-10836303/3-point-bendingtest-setup-2.hm.html These are some screenshots of the different views on the model:By property, 2D detailed http://www.pic-upload.de/view-27981011/Forum-by_prop.png.htmlBy component, 2D detailed http://www.pic-upload.de/view-27981021/Forum-by_comp_2D.png.htmlBy component 2D traditional http://www.pic-upload.de/view-27981023/Forum-by_comp_1D.png.html I hope you get my problem and can help me fix it. Thanks in advance!