HyperMesh学习的一些建议：

CAE部车身分析科的三个方向：

①NVH（noise，vibration, harshness） ②Structure ③Crash&Safety

HyperMesh学习的一些建议： 1快捷键的使用：

常要使用的快捷键是12个功能键和Shift与12个功能键的组合。

2以白车身建模步骤为例来说明HyperMesh建模的基本步骤

①从UG或其他CAD软件中导出（export）iges（基本图形转换规范，文件的扩展名是igs）文件。

②将导出的iges文件导入（import）HyperMesh，导入后一般会自动生成一些collector。应根据具体模型，将不同的零部件所对应的surface并入到不同的collector中，然后在模型树（model browser）具体操作： ★ Import文件 Files：

中分别选择不同的部分划分网格。

★ 为不同的零部件所对应的surface创建相应的collector

可以先在collector菜单中创建一个新的collector并在organize菜单中将所有的surface move to 或者copy to(点击surface进去点一下duplicate到这个目标collector（destination）中。

③划分网格前的几何清理：

对于不同的试验目的和要求，在划分网格方面有很多经验性的东西。 Hypermesh划分网格的一些经验总结：

安全碰撞（Safety Crash）网格的划分： ★ 测估圆的半径的简单操作

F4->two nodes:

- In the graphics area, hold down the left mouse button and place the mouse cursor on top of the line defining the remaining hole.

-When the line highlights, release the left mouse button to complete the selection.

The line remains highlighted. Clicking anywhere on the line will generate a temporary node. -Click two locations diametrically opposed on the circular hole. HyperMesh generates two temporary nodes, N1 and N2.

The distance = field displays the distance between these two nodes, and reads a value that approaches diameter of the circle.

Toggle:

2N cut：

fixed points

Spline

④划分网格后的单元质量检查 单元检查

首先要保证的是没有free edge（tools->edges）。再进行单元检查（F10）。

angle是检查单元的最大最小角的。一般情况下，用check elems里的标准就够了，也可以宽松点。

另外，补充一点，可以把生成的体单元find faces，mask掉其余单元，然后用功能键F1，选择cutting，在任选一个plane（能截开体单元的面）和trim plane，拖动鼠标左键，就可以看到单元内部是不是有空隙了（没有空隙时只有一个闭合的蓝色曲线），对于手工生成的6面体网格是比较有用的。 Criteria Min Definition Ideal Average elem size Average elem size 1.0 0.0 Worst 0.0 ∞ ∞ 90 size Length of the smallest side of an element. Length of the largest side of an element. Ratio of longest side to the shortest side of an element. Maximum angle between the two planes of triangles created by splitting a quad element diagonally. This check is performed only for quad elements. Max length Aspect ratio Warpage Max angle Maximum internal angle of a quad element. quad Min angle Minimum internal angle of a quad element. quad Max angle Maximum internal angle of a triangle element. tria Min tria Skew angle Minimum internal angle of a triangle element. For quads, it is calculated by finding the minimum angle between two lines joining opposite mid-sides of the element. In trias, it is calculated by finding the minimum angle between the vector from each node to the opposing mid-side and the vector between the two adjacent mid-sides at each node of the element. 90 90 60 60 0 180 0 180 0 90 Jacobian A measure of the deviation of a given element from an ideally shaped element. The check is performed by mapping an ideal element in parametric coordinates onto the actual element 1 -1 Chordal dev The farthest distance between the middle of an edge to its project on the corresponding surface ( or inferred surface). % of trias Ratio of number of trias to total number of elements (displayed). 0 user-defined [Ref. HyperMesh-> Help->quality index] 若做项目，应当根据客户的要求。

⑤2维单元的优化

一种方法是remesh/elements，选中一个小区域把这些质量比较差的单元包括进去，remesh；

一种方法是2d/quality index, 在右边view的下拉框里选择edit or optimize，然后就勿需多说了；

一种方法是彻底的remesh，修改你的划分思路，把复杂曲面划为几个简单些的曲面，或寻找其它更好的剖分方法。

★ 创建材料集和单元属性集，并将材料和单元属性赋给部件（component） ①选定user profile为Ls-dyna模板

②导入材料曲线

③在collectors中建材料集和单元属性集 F11或tool－>collectors

赋材料

赋单元属性

材料属性参数说明

MAT1 Material Property Definition, Form 1(各向同性材料).

Defines the material properties for linear, temperature-independent, isotropic materials.

MID Unique material identification number (Integer > 0). E Young’s Modulus (Real or blank). G Shear Modulus (Real or blank).

NU Poisson’s Ratio (-1.0 < Real < 0.5 or blank). RHO Mass density (Real).

A Thermal expansion coefficient (Real).

TREF Reference temperature for thermal loading. Default=0.0 (Real).

ST, SC, SS Stress limits in tension, compression and shear. Used for composite ply failure calculations (Real).

MAT2 - Material Property Definition, Form 2(各向异性材料)

Defines the material properties for linear, temperature-independent, anisotropic materials for two-dimensional elements.

MID Unique material identification number (Integer > 0). Gij The material property matrix (Real). RHO Mass density (Real).

Ai Thermal expansion coefficient vector (Real).

TREF Reference temperature for the calculation of thermal loads (Real or blank) (See Remark 6).

ST, SC, SS Stress limits in tension, compression and shear. Used for composite ply failure calculations (Real).

MAT8 - Material Property Definition, Form 8(二维正交异性材料).

Defines the material property for an orthotropic material for two-dimensional elements.

MID Material ID (Integer > 0)

E1 Modulus of elasticity in longitudinal direction (also defined as fibre direction or 1-direction) (Real 0.0).

E2 Modulus of elasticity in lateral direction (also defined as matrix direction or 2-direction) (Real 0.0).

NU12 Poisson’s ratio ( for uniaxial loading in 1-direction). Note that for uniaxial loading in 2-direction is related to by the relation . (Real). G12 In plane shear modulus (Real > 0.0). G1,Z Transverse shear modulus（横向剪切模量） for shear in 1-Z plane (Real > 0.0 or blank).

G2,Z Transverse shear modulus（横向剪切模量） for shear in 2-Z plane (Real > 0.0 or blank).

RHO Mass density (Real).

A1 Thermal expansion coefficient in 1-direction (Real). A2 Thermal expansion coefficient in 2-direction (Real).

TREF Reference temperature for the calculation of thermal loads (Real or blank) (See Remark 3).

Xt, Xc, Yt, Yc Allowable stresses or strains in the longitudinal and lateral directions. Used for composite ply failure calculations (Real > 0.0).

S Allowable for in-plane shear for composite ply failure calculations (Real > 0.0). F12 Tsai-Wu interaction term for composite failure (Real).

STRN Indicates whether Xt, Xc, Yt or Yc are stress or strain allowables (Real=1.0 for strain allowables).

MAT9 - Material Property Definition, Form 9(各向异性材料)

Defines the material properties for linear, temperature-independent, anisotropic materials for solid elements.

MID Unique material identification number (Integer > 0). Gij The material property matrix (Real). RHO Mass density (Real).

Ai Thermal expansion coefficient vector (Real).

TREF Reference temperature for the calculation of thermal loads (Real or blank) (See Remark 5).

★ 创建焊点和螺栓的刚性联结，以及创建卷边 ①偏置单元，使零部件处于正确的装配位置 2D->Offset element

②创建三个Components分别用于存放spotweld、rigidbody、flange，一般三层焊点也放在rigidbody里。 ③创建焊点

创建焊点的一般原则：根据零部件的主从关系来确定焊点的主从关系（independent和dependent）。焊点可根据CAD中的焊点图来布置。 1D->spotweld->using nodes ④创建螺栓的刚性联结 1D->rigids->create ⑤作卷边

Most Critical(Zone 1: Impacted Zone) Vehicle Components Front side rails/front horn Shotgun/apron Aft rail Front floor Torque box Front bumper Shock tower Sled runner Toe board area mid rail Radiator support Front steel A-pillar/roof rail joint A-pillar/hinge pillar joint Truck frame/rail Moderately Critical(Zone 2: Partial) Translation Mesh Size(mm) Vehicle Components dash A-pillar Hinge pillar cowl Instrument panel Front subframe Front rocket Roof rails B-pillar/roof rail joint B-pillar Cross members Rear rocker mid floor Translation Mesh Size(mm) Less Critical(Zone 3: Non-impacted Zone) Vehicle Components trunk Rear floor Rear subframe Engine and its accessories transmission Roof panel

Translation Mesh Size(mm)

Vehicle Components dash A-pillar Hinge pillar cowl Instrument panel Front subframe Front rocket Roof rails B-pillar/roof rail joint B-pillar Cross members Rear rocker mid floor Translation Mesh Size(mm) Less Critical(Zone 3: Non-impacted Zone) Vehicle Components trunk Rear floor Rear subframe Engine and its accessories transmission Roof panel

Translation Mesh Size(mm)

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