有限元分析：究竟什么是好網(wǎng)格？

Good mesh need resolve physics, not follow the CADmodel.

好網(wǎng)格應(yīng)該很好地描述物理本質(zhì),而不是符合CAD模型。

A good mesh is always associated with the physics. Whenyou change your boundary conditions, or change your loadconditions, or change analysis types, or change flow models, goodmesh (with the identical geometry) may turns to be badmesh.

好網(wǎng)格必須始終反應(yīng)物理本質(zhì)。當(dāng)你改變邊界條件、載荷、分析類型或者流體模型時(shí),質(zhì)量好的網(wǎng)格可能會(huì)變成差網(wǎng)格。

The accuracy advantage of hex meshis no longer existing anymore, for most engineering problems.

對(duì)于很多工程問(wèn)題,六面體在精確度上的優(yōu)勢(shì)已經(jīng)不存在了。

When the software vendor needjustify that his meshing software is in the high-end (of courseprice is usually in the high end as well), he will tell you thesoftware allows you to all sorts of manual controls. The hiddeninformation is only manual controls can generate better mesh.

當(dāng)軟件供應(yīng)商向你推銷網(wǎng)格劃分功能時(shí),他會(huì)告訴你這款軟件支持各種各樣的手動(dòng)劃分網(wǎng)格的方法。隱含意思就是手動(dòng)控制網(wǎng)格才能得到好網(wǎng)格。

Yes, to salesman, good mesh need manualcontrol. But to engineer, you need understand this is misleading. Agood meshing software should have the intelligence to analyze theunderlying geometry: calculating curvatures, finding gaps; findingsmall features; finding hard edges; finding sharpangles, applying sensible default settings….

是的,對(duì)于銷售者來(lái)說(shuō),好網(wǎng)格需要手工控制。但對(duì)于工程師而言,你應(yīng)該知道這其實(shí)是在誤導(dǎo)。一個(gè)好的網(wǎng)格劃分軟件應(yīng)該智能地去分析它將要?jiǎng)澐值膸缀文Ｐ?計(jì)算曲率、識(shí)別間隙、識(shí)別小特征、識(shí)別銳邊、識(shí)別尖角,然后進(jìn)行合理的默認(rèn)處理(無(wú)需人工干預(yù))。

<譯者按:這也許是前處理軟件的發(fā)展趨勢(shì)>

Fine mesh does not mean good mesh.The purpose of meshing is toget solutions in discrete locations. Good mesh is the mesh thatserves your project objectives. So, as long as your results are: 1)physical; and 2) accurate enough for yourproject, your mesh is sufficiently good.

精致的網(wǎng)格不等于好網(wǎng)格。畫網(wǎng)格的目的是得到離散點(diǎn)上的值。只要能滿足工程需要就是好網(wǎng)格。保證兩點(diǎn):1)表達(dá)物理本質(zhì);2)達(dá)到工程所需的精度。

Another example of thismisunderstanding is that most users always use full 3D model. Intheir eyes, 3D full model is “realistic”. However, if the problemis symmetry, using portion of your geometry (therefore lessnodes/elements) will produce better results because the symmetriccondition is exactly enforced. If the problem is axis symmetric, 2Dresults is far more accurate than most 3D results.

這一誤區(qū)的另一個(gè)表現(xiàn)是:總是使用完整的3D模型。在他們眼里,完整的3D模型才是最逼真的。然而,如果問(wèn)題是對(duì)稱的,使用模型的一部分(這樣可以減少節(jié)點(diǎn)和單元數(shù)量)可以獲得更好的結(jié)果(因?yàn)檫@樣會(huì)精確反應(yīng)對(duì)稱性)。如果問(wèn)題是軸對(duì)稱的,使用2D模型比3D模型更精確。

Currently, CAE still replieson meshing. Good mesh should:

1. be able to resolve the physics to bestudied;

2. have reasonable quality so that the solver will notfail;

3. simplify the geometry based onphysics;

4. be problem specific;

5. meet your project requirements

目前,CAE仍然依賴于網(wǎng)格劃分。好網(wǎng)格應(yīng)該做到以下幾點(diǎn):

1、能夠解決所研究的物理問(wèn)題;

2、網(wǎng)格質(zhì)量合理,避免計(jì)算失敗;

3、基于物理本質(zhì)簡(jiǎn)化幾何模型;

4、具體問(wèn)題具體對(duì)待(對(duì)同一個(gè)幾何模型做不同的分析,可能需要?jiǎng)澐植煌木W(wǎng)格)

5、滿足工程需求

內(nèi)容轉(zhuǎn)自:

http://caewatch.com/top-5-misunderstandings-on-good-mesh/