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!