複合材料碳纖維分析說明

Nastran in-CAD 分析複合材料碳纖維案例

A composite bicycle frame model made of 2D orthotropic carbon weave material is created. Loads are applied and a static analysis is performed using a laminate element made up of multiple plies at various ply angles. Results are presented using various graphic visualization methods and the use of several failure criteria are illustrated.

Nastran in-CAD 分析過程中所需要的功能步驟

Composite materials analysis imposes a number of requirements that are significantly different when compared to isotropic materials and FEA software used for composite analysis must be designed to handle the anisotropic nature of composites and the failure mechanisms associated with their properties like cracks, delaminations, and fiber failure. In addition, high quality FEA software should include features that make it easy to use while providing the engineer with the power to get results that are practical and truly valuable for application to real world problems. NeiWorks fills this need for composite designers with a number of features in model creation, material definition, meshing, post processing, failure criteria, and data presentation.

 
1. User friendly definition of material properties
2. Definition of ply lay-up
3. Easy orientation definition
4. Outer mold line representation
5. Post processing visualizations that pinpoints problem areas
6. Failure Indices and Strength Ratio
7. Import 3D CAD models
8. Sensitivity and configuration trade off studies
9. Progressive Ply Failure Analysis (PPFA™)

1. 功能強大且簡潔易用的材料性質設定介面

Clear, easy input of strength and stiffness terms with access to material libraries.

 

2. 簡潔易用的複材疊層定義方式

Stacking sequences can be quickly and easily entered into a table, and symmetry can be used to reduce entries. Modification and changes are easily made and the chance of error is greatly reduced.

 

 

3. 強大的曲面纖維定位功能

Curved surfaces can complicate the orientation of fibers. NEi Nastran can project a cylindrical or spherical coordinate system onto a structure to get good representation of ply orientation. Advanced application can carry out draping analysis with Simulayt if this degree of fidelity is required.

 

4. 外部模線顯示功能

 

5. 視覺化後處理圖形可精確找出問題區域

Enormous amounts of data can be involved in multi lay-up and multi ply structures. NEi Nastran provides a logical path from stress analysis of a structure to Failure Index results that can isolate problems and pinpoint them to definite regions on specific plies.

 

 

6. 破壞指數與強度比

NEi Nastran supports all the major composite failure analysis indices Tsai-Wu, Hill, Hoffman. Plus NEi Nastran includes the most modern forms of Puck and NASA Langley LARC02. In addition, the Strength Ratio is available for easy linear scaling and qualitative analysis.

 

NASA Langley has developed LARC02, a set of first-ply-failure criteria which have shown to be accurate and physically consistent. It is well suited for design purposes because it balances accuracy, material characterization requirements, computational effort, and ease of results interpretation.

     

 複合材料高階破壞準則

 

  • LaRC02 Set of Criteria
  • Developed by NASA
  • First-ply-failure
  • Physically based
  • Hashin, Puck approach
  • No additional material properties required compared to Tsai-Wu
  • Failure mode taken into account
  • Extensive validation (WWFE)

 夾層結構之穩定指標輸出

Theory based on Facesheet Wrinkling in Sandwich Structures, NASA-CR-1999-208994, 1999

Honeycomb Sandwich Material Properties

Material
Modulus of Elasticity (msi)
Tensile Limit (ksi)
Compression Limit (ksi)
Shear Limit (ksi)
Aluminum Face Sheets
10.0
35.0
35.0
23.0
Honeycomb Core
0.1
0.1
0.3
0.2
Bonding Material
-
-
-
0.1

 

 

7. 3D CAD Models

For SolidWorks users, NEi Works is embedded, completely eliminating the need to import files.

 

8. 靈敏度和配置權衡研究

NEi Nastran Editor feature is perfect for composite analysis because it provides an easy inexpensive way to do sensitivity and configuration trade off studies.

 

  • Features tabbed windows to give immediate access to all input and output files
  • Field markers make manual editing simple and increase productivity dramatically
  • Complete online documentation and context sensitive help
  • Permits batch queuing of jobs for sensitivity and configuration trade studies
  • Special real time controls allow changing solution parameters while running
  • Real time 2D xy-plotting and 3D deformed shape and contour plotting

 

 

9. 漸近式疊層破壞分析 Progressive Ply Failure Analysis (PPFA™)

allows engineers to examine composite structural behavior beyond first ply failure. Reduce weight and material costs while saving time in analysis by efficiently analyzing residual strength, local damage effects, temperature effects, post-FPF (First Ply Failure) events, separation, ultimate failure, design modifications, and ultimate strength with PPFA.