Search the Community
Showing results for tags 'symmetry'.
Found 6 results
-
Dear CFD users, I am desperately trying to create a 3d cfd mesh with BL using Hypermesh. My geometry is perfectly connected with the control volume faces and the surface mesh created on the geometry (defined as "wall") and the control volume faces has passed all sanity checks (connected elements, no duplicates, no free edges) resulting to a "watertight" 2d mesh ready for 3d meshing. With these conditions a 3d mesh from the 2d boundaries is created without any problems. My problem is to create a 3d CFD mesh with a given boundary layer on the component named as "wall" (which is the body that I wish to investigate). Although the mesh is created (with the boundary layer specified), it is not connected to the symmetry plane as I want: I was expecting to see only the elements of of the symmetry plane to change their topology ("shape") in order to connect with the boundary layer created on the wall and the rest elements remaining as they were (or close). Not only this does not happen, but a BL is created both on the wall elements and all elements of the surface plane. The attached images show the control volume and describe the problem I am facing. Could you please let me know if what I want can be done in Hypermesh? How do I define my 3d meshing strategy in the CFD option? Thank you in advance for your kind assistance.
-
CAEでは計算時間を短縮するテクニックの一つとして、対称条件を使う方法があります。 モデルも拘束条件も荷重条件も対称であれば、計算モデルを対称面で切って1/2や1/4にすることで、必要なメモリや計算時間を大幅に削減することが可能です。 面対称だけでなく、周期対称や軸対称の構造モデル化もHyperMeshで可能です。 ここでは、対称条件モデルを作る上で必要なモデリング＆ビジュアライゼーションテクニック（下記１～３）をご紹介します。 １．メッシュを作成する範囲は構成対象の一単位とする たとえば上記の様に左右面が対称の場合、片方のみの領域にメッシュを作成します。 もとのジオメトリ情報が面データであれば、メッシュを切る前にあらかじめ対称面で区切っておくなどしておくとメッシュが作成しやすいです。 ジオメトリを面で区切る処理に使われる操作は geometry > surface (solid) edit > trim with plane ２．対称性を考慮した境界条件を付与する 上記例の場合、YZ対称メッシュなので、境界部分に拘束DOFを156（X並進とY軸回転Z軸回転を拘束）と指定して設定します。 。 この処理に使われる操作は Analysis > constraints ３．フルモデル表示で解析結果を確認する モデルは最小単元の計算範囲ゆえ、フルモデルで作った場合に比べて短時間で解析の結果が確認できます。 このモデルによる結果を、表示上フルモデルで確認したい場合は、HyperViewのsymmetry機能で表示が可能です。 この処理に使われる操作は HyperView > symmetry 対称モデルはほかにも周期対称や軸対称もあります。 いずれも、最小単元の領域にメッシュを作成し、境界部分に適切な条件を付加することで表現できます。 以下の対称モデルの場合の例 左側：HyperMeshで1/36解析モデルの作成、中央：HyperViewでフルモデル表示、右側：結果値マップ
-
Hi, everyone. I encountered a problem when morphing an arc. The arc cannot keep the tangency on symmetry plane when altering the radius of the arc (shown in figure). How to keep the vertical tangential direction on point B and D while morphing? Thanks. Morph_ArcTangent.hm -
Can we use symmetry in modal analysis? When I did with symmetry and without symmetry, I noticed huge difference in the first modal frequency. And this forum, advices against using symmetry for modal analysis http://www.eng-tips.com/viewthread.cfm?qid=333936 But my part is a simple plate where even the constraints are also symmetric. Can anyone adivce me on this. Thanks.
-
Hello at all, during a topology optimization i wanted to add a pattern grouping to get symmetry. But i ´ve got the same results in 1-plns sym, 2-plns sym and 3-plns sym. So i can´t see the differences between the pattern grouping modes and how to use them correctly. Please, is there someone who could explain the different types of pattern grouping and their fields of application? Thanks a lot! Rizzo
-
Hello everyone, quick question that Google did not give me an answer for and I am a Little pressed for time. I have surface an would like to apply a stacked Laminate on top of it, so that the surface is used as base for the Laminate. However, whatever Setting I use, the Laminate always turns out to be symmetric, to each side of the surface. I cannot possibly work with a symmetric Laminate as I have constraints regarding the size of my part. The surface marks the outermost surface of my part and thus cannot be exceeded by a Laminate. I have tried the STACK Option in the Laminate creation tool but this did not seem to help. Any help would be greatly apprechiated! Greetings, Lenny
