Element specific distortion checks
Deviation form basic shaped elements, i.e. taper
Curvature and singularity tests for quadratic elements Color-coding based on node or element ID numbers
Gap
NonCongruen
t Surface boundarie
s
➢ Reduce cost ➢ Increase productivity ➢ Build quality finite element models with minimal user
interaction
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Simplify Merge Faces Merge 16 pseudo faces into 1 face
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User Scenario 1
➢Additional manual mesh simplification
1 face
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CAE模型的建立
➢根据计算机的能力和要求的精度确定合 适的网格大小，划分网格。如果机器的 能力和时间允许，可以将单元尺寸划分 的小一些（但不能太小），如可以按照 碰撞的计算要求进行划分，这样同一个 模型既能够计算模态分析，有可以模拟 碰撞.
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修改设计
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几何模型修正
➢ 在建立几何模型的过程中,有可能发生 几何特征缺失或者产生一些不必要的小 碎面，这些几何错误都需要进行清理， 否则会影响有限元模型的质量、计算的 精度和速度，具体的方法是进行缝合、 修补或合并。可以将N个面合并成一个 面（此种方法只限对模型质量要求不高 的情况），但关键的特征线应该保留， 如拐角、和孔等。
Trimmed surface with hole
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Point 44
New Vertex
Trimmed surface
Parametric surface without hole
Trimmed surface 4 Remove Vertex
Parametric surface
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➢Pseudo surface cleanup
➢Create congruent meshes (based on user defined tolerance)
➢ Select initial tri-mesh ➢ Set tolerance to .1
➢Many internal free edges
Overlapped Surface boundaries
Gap
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User Scenario 1
➢Create initial tri-mesh
➢Pseudo surfaces Initial Mesh
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User Scenario 1
➢Verify : Surface : Boundary
➢Many internal free edges
Gap
Non-Congruent Surface boundaries
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User Scenario 1
➢Verify : Surface : Boundary
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几何模型修正
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SURFACE EDIT
11
3 2
Complex mathematical representation
1 2
3
4 5 6
Surfaces have continuous slope
1
2
parametric cubic mathematical representation
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IRREGULARITY CHECKS
General mesh/element checks
Boundary or “Crack” detection Elements Duplication Normals Nodal connectivity Jacobian
User Scenario 1
➢Create initial tri-mesh
➢Pseudo surfaces
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User Scenario 1
➢Pseudo surface cleanup
➢Verify element free edges Cleanup
Verify Free edges
白车身模态分析流程及建模标准
概述
1.几何模型修正 2.几何模型读取 3.单元尺寸的定义和模型划分 4.模型的合并 5.施加载荷和边界条件 6.分析计算 7.结果的后处理 8.修改设计
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分析流程图
几何模型修正 几何模型读取 单元尺寸的定义和模型划分 模型的合并 施加载荷和边界条件 结果的后处理
➢Use polygon pick to select the entire gap
➢Repeat for all known gaps
This tool will close the gaps of areas defined by the selected edges. Also, This tool will close the gaps without any checking of tolerance values.
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User Scenario 1
➢Additional manual mesh simplification
➢Merge pseudo faces to eliminate skewed or sliver surfaces ➢Create higher quality final mesh
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焊点的连接方式
➢ 在给出的焊点坐标附近，用两个RBE2 单元连接，或采用一个零件（厚度较大 的零件）的节点做主点，相连零件的两 个节点做从点的方法。三层板件焊接， 中间点作为主点。一般不推荐一个焊点 只采用一个RBE2单元（只有两个节点 连接）的方式。
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VERIFY ELEMENT BOUNDARY
Plots the boundary as free edges, or optionally free faces Free edge/face of an element is the edge/face of the element
not common (tied to) with others Cracks or free edges appear along geometric boundaries prior
to equivalencing
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VERIFY ELEMENT BOUNDARY FREE EDGES
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1
2
Can use simultaneously with all surfaces
PATRAN相关的几何模型修正
Parametric Point 35 Surface 6
Trimmed surface 8 with hole
Parametric Surface 2
➢ 2 gaps needs to be manually stitched
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User Scenario 1
➢Pseudo surface cleanup
➢Stitch free edges
Stitching
➢ Select free edge
➢ Use “ Free Edge of 2D Element“ selection icon
Warp
Skew
Taper
模型的合并
➢ 一个白车身由若干个零件组成，模型的合并是一个 复杂的事情。一般情况下有两种办法：一种是先进 行各大总成的合并，如侧围、地板等，各个总成合 并完成后，再进行白车身的合并。此种办法比较简 单，而且焊接顺序可以结合车间的焊接顺序进行， 比较容易理解，建议初学者使用。另一种办法是将 所有的模型全部读入，然后依次将各个零件进行焊 接。按照此种办法，需要对车身结构和焊接非常了 解，连接过程中经常会遗漏部分焊点，需要反复几 次计算才能全部完成。但这种方法有助对白车身的 透彻了解。建议熟练后采用。
Dashed (blank) area indicates more than one tet
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Free edge display
Free edge display after
before equivalencing equivalencing
网格划分Advanced Surface Mesher
➢ Benefits
➢ Drastically reduce analysis modeling time