Dear Sir
i have a CT scan data patient spine. I created a 3d model in mimics, it has 8 vertebrae. Then i scale anybody modal according to patient height and weight. Then i observe anybody model spine has 14 vertebrae. Sir i have to done the fea analysis as my previous project. I think geometry of both spines are same but length is the problem. Sir plz tell me the procedure that how to reduce the no of vertebrae in anybody model.
Thanks.
Mohit,
Vertebrae of the lumbar spine: You need to scale an ANyBody model to the subject-specific size for this bones - read tutorials on Scaling that describes how to get consistent geometries between simulations. Once done you can export loads for all vertebrae of the lumbar spine like discussed in other sections.
But unfortunately it is not possible to do with the thorax - at this point this complex is a single segment and you would need to do a partial scaling for the region that you have and leave the rest of the complex to be scaled anthropometrically. This is a quite hard problem. However, if you join all those segments into one - it may still be possible to apply all loads from the thorax using the standard procedure.
Regards,
Pavel
Dear Sir
I need only spine scaling in this problem.Because i have to calculate muscle forces only on spine.
Sir if i want to calculate forces on femur which have a implant(shown in figure).
Is loads will occur properly at region of implant as in case of bone without implant? Or how loads act at implant due to presence of muscles attachment.
Thanks.
Mohit,
I don’t understand the spine part. Please ask specific very questions, explain your problem - unfortunately we cannot answer badly stated or “I cannot construct a model” questions.
The transfer of the femur loads will work exactly like for an intact femur unless you do something special about that. It will find the closest nodes on the mesh and make constraints. You could try and see what happens - i expect that the joint load will be applied close to the tip of the implant, where it needs to be. Whereas some muscle attachments may be misplaced - you can modify manually or programatically those that do not look good.
Regards,
Pavel
Dear Sir
Sorry for last reply, but intention for the spine part that we don’t want to scale thorax because in yours last reply you discussed about that.
Sir CT data spine is in lying down position and shape of spine changes due to that. For the scaling purposes i exported the anybody bone from standing model. so now there is shape and geometry difference between both bones.
Sir is it a right approach to do scaling or i have to first change standing model to lying down position for exporting spine in same posture?
Thanks.
Hello Mohit,
No, by default loads will be applied to the implant too. It will depend on the shortest distance between muscle/joint reaction force action point and the mesh. You would need to do the modifications of the generated files to get them separated.
Spine: scaling happens for each bone in the local reference frame so the total shape changes. The joint nodes that are outside of the geometries will be extrapolated so please use the bounding box options for scaling. Please check the tutorial for that.
Kind regards,
Pavel