Simulation of laminate composite space antenna structures

Transcription

1 Sairam Prabhakar Simulation of laminate composite space antenna structures Femap Symposium 2014 May 14-16, Atlanta, GA, USA FEMAP SYMPOSIUM 2014 Discover New Insights

2 Agenda Background Workflows for modeling composite antenna structures FEMPLY to pre-process composite structures Post-processing laminate composite structural analysis with FEMPLY SA Toolkit for rapid random response analysis Page 2

3 Laminate composites for space structures Why Composites: Lighter $10,000 - $100,000 to put a pound of payload into orbit 20% lighter than Aluminum Stiffer Directional stiffness which can be tailored High modulus Carbon fibers 350 GPa Radarsat1 Source: Wikipedia Thermally Stable Can design zero Thermal Conductivity Page 3

4 Next Generation Composites: MDA Medium-Sized Reflector Medium (0.9 m dia) reflector developed by MDA Corp and Composites Atlantic One of the early composites reflectors: light, stiff and exceptional thermal stability Technology now used by ESA Sentinel satellite program, Intelsat, and Boeing Significant profitability: Original development funded by Canadian Space Agency grant of $939,000 Revenue generation of ~ $5 Million annually for MDA Corp Source: MDA Corp Page 4

5 Introduction to MAYA MAYA Simulation is a developer of leading-edge software packages for a variety of engineering applications Thermal, CFD, structural, laminates, NVH, durability Strategic Partner of OEM provider of software products and components since 1986 VAR in North America, specializing in CAE 105 employees 75 technical staff, 24 Ph.D s Extensive experience in CAE consulting using SPLM tools Page 5

6 MAYA Simulation Technologies Over 2 decades of structural analysis experience: specifically in composite satellite structures Structural customers include MDA, Bristol Aerospace, Composites Atlantic,. Recent successes: RADARSAT and CASSIOPE FEMAP and NX for Pre/Post. NX Nastran for solving Page 6 Source: CSA

7 Key steps in structural analysis of composites Defining layup: Global ply definitions Drop-off definitions As-manufactured fiber orientations: Draping simulation Orientation-consistent NASTRAN PCOMPs Ply-wise results processing User-defined failure indices from NASTRAN computed stress/strain results Page 7

8 What is FEMPLY FEMPLY is a Composite Ply-Based Modelling tool fully integrated into Siemens FEMAP Pre/Post-processor offering fast, efficient and simple definition of complex component layups. FEMPLY Pro extends the functionality by adding: Ply Draping Flat Pattern Export Laminate Failure Calculations Sandwich Stability Calculations Failure Envelope Charting Page 8

9 What is Ply-based Modeling Layup Based Modelling Ply Based Modelling User Defines Layups / Properties User Defines Ply Extents User Applies Properties to Parts of the Model Layups / Properties Automatically Created and Properties Applied to Parts of the Model Page 9

10 Why Perform Ply-Based Modeling? Layup Based Modelling Ply Based Modelling No. of Plies to define. 4* 4 No. of Layups to define. 7 1 No. of Properties to define. 7 - Total User Inputs. 4*+7+7=18 5 *If Post-processing using global ply IDs is required Page 10

11 Key Features: Simple Ply Definition Page 11

12 Key Features: Remapping plies on Remeshing Page 12

13 Key Features: Ply Draping Export draped patterns to DXF Draping results can be used to apply properties with modified fibre angle. Ply Interior holes are handled Page 13

14 Key Features: Advanced Post Max Stress/Strain Tsai-Wu Hill Hoffman Puck LaRC02 Layered Results as well as Critical Ply and Fibre Angle Output Vectors are created. Page 14

15 Key Features: Post-processing sandwich panels Skin Wrinkling Shear Crimping Honeycomb Dimpling Critical Direction and Face Output Vectors are created. Page 15

16 Key Features: User Defined Failure Theories No Programming Skills Needed. Ply stresses, strains and moduli available as variables Multiple Conditions Page 16

17 Key Features: Reporting Plot Ply Failure Envelopes Export Bill of Material and Layup data to MS Word Export Laminate and Sandwich Failure calculations to MS Word Page 17

18 Structural Analysis Toolkit (SA Toolkit) for NASTRAN Efficient and accurate random and sine solutions from NASTRAN normal modes results Efficient post-processing of Nastran results Ranking, sorting, enveloping, filtering Summaries by groups, subcases, etc. Margins of safety for different failure types Direct manipulation of.op2 file data Extremely efficient for large models Support NX, MSC Nastran Windows & Linux Automatic Report Generation HTML, MS Excel, ASCII Page 18

19 SA Toolkit Suite Random vibration processor Sine vibration processor Modal processor Energy processor Mass processor Stress processor Grid point force processor Element force processor Page 19

20 SA Toolkit Random Processor SAToolkit Random Processor Statistics are required to assess the probability of the response s magnitude Random theory assumes that the input follows a Gaussian distribution. The same assumption applies to the response Page 20 Source: Wikipedia p x 1 2 ( x) e

21 SA Toolkit Random Processor Examples of response quantities that do not follow Gaussian distributions Von Mises stress Source: Wikipedia 21 Page 21

22 SA Toolkit Random Processor Examples of response quantities that do not follow Gaussian distributions Tsai-Wu composite failure index Page 22

23 Evaluation of non-gaussian responses To evaluate response quantities that do not follow Gaussian distributions, numerical approximations are required: Segalman or Fast approximation method for Von Mises stress Also need to validate the approximation using Monte Carlo simulation Page 23

24 Peak Results True peak stresses and failure metrics based on a probability level that is either: Directly specified, OR Equivalent to a Gaussian pdf with specified standard deviation eg 99.73% = 3 sigma Page 24

25 Efficient and Accurate Interpolation Uses NX Nastran eigenvectors from a SOL 103 run High-performance integration algorithm Does not require frequency card (FREQ) definition Avoids the risk of error by under-specification of number of computation frequencies Only need to supply the minimum and maximum frequency bounds for the simulation Page 25

26 High Performance Solver Composite tube model benchmark 29,000 solid elements 60 plies defined on PCOMPS card SOL 103.op2 file size: 1.82 GB Stress request: Bottom/middle/top Peak ply stress extraction: 58 secs Peak max stress failure index extraction: 1 min 12 secs Page 26

27 Random Ply Results Elemental Ply stresses, strains Homogeneous stresses and strains, Von Mises stresses Shell resultants, 1D and 3D element forces Nodal Acceleration, displacement, velocity, grid point force, mpc force, spc force Relative or absolute displacements, velocities and accelerations Number of positive crossings All entities or selected groups N0 U U 2 2 S( ) S( ) d 1 1 L U 2 2 S( ) d L L d RMS Page 27

28 Compensation for Modal Truncation Modal Truncation Effects Account for modal truncation effects via either: Residual vectors via the NX Nastran RESVEC Case Control request, or Residual flexibility approach via the supplied DMAP Page 28

29 Conclusions FEMAP is an effective pre/post environment for laminate composite antenna structure analysis FEMPLY provides enhanced workflows for composites structural analysis: Global ply based modeling Ply draping simulation Efficient results processing Complete set of polynomial and advanced failure theories User-defined failure theories SA Toolkit provides a fast and powerful tool for random response analysis Page 29

30 Contact Sairam Prabhakar Senior Technical Specialist MAYA Simulation 4999 St. Catherine West Montreal, QC, H3Z 1T3 Phone: Fax: (514) Mobile: (514) Page 30