2. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates Numerical Simulation of Impact on Composite Laminates M.A.G. Silva and C. Cismasiu Centro de Investigaçao em Estruturas e Construção-UNIC, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Monte de Caparica, Portugal C.G. Chiorean Faculty of Civil Engineering, Technical University of Cluj-Napoca, 15 C. Daicoviciu Str., 3400 Cluj-Napoca, Romania Last Updated: 03 June 2014

3. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates Numerical simulation of impact problems on composite laminate plates reinforced with Kevlar 29/Epoxy. Low velocity impact produced using Rosand Precision Tester. Estimate the V50 and the global damage caused by a STANAG-2920 projectile. Objectives

4. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates Material Model The following phenomena may need to be modelled for composite materials under ballistic impact: Material anisotropy Shock response Coupling of volumetric and deviatoric behavior Anisotropic strength degradation Material compaction Phase changes

5. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates Advanced Orthotropic Model An advanced model for orthotropic materials subjected to high and hypervelocity impact. Features: Couples the Non-Linear Equation of State and orthotropic stiffnes matrix Compaction and orthotropic brittle failure criteria to detect directional failure initiation Orthotropic post failure response in predicting delamination of fibre reinforced composite materials

6. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates Laminated Composite Model Orthotropic Post-Failure Response for Orthotropic Materials Dominated Failure Modes in Laminated Composites are: Delamination caused by through thickness failure or shear failure in matrix Tensile fibre failure- in plane failure of fibres Combination of delamination and tensile fibre failure, leading to bulk failure Equivalent orthotropic material properties Laminated composite Equivalent model- individual layers not represented explicit

7. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates Impact Analysis The interactive non-linear transient dynamics analysis software Explicit finite difference techniques Lagrange processor including erosion techniques Advanced robust automatic dynamic contact logic Orthotropic material models and extensive built-in materials database

8. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates Numerical Model Used in Low Speed Impact Simulation Target: Circular Kevlar 29 plate with radius of 50 mm and thickness 1.8 mm Projectile: Steel 4340 Sphere with radius 5 mm. Mass=3.867 kg The Lagrange processor was used for projectile and target Uniform cells of side 1.25 mm were used in the central impact area Interaction: impact-slide logic with a gap size 0.053 mm Hourglass damping increased to 0.15

9. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates Deflection History Energy level 2JEnergy level 5J Energy level 10J Energy level 20J

10. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates Maximum Deflection and Coresponding Peak Time Maximum error: 11% (E=2J) Minimum error: 2% (E=20J)

11. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates Maximum Impact Force and Coresponding Peak Time The peak of the impact force was computed according to the Hertzian contact model. Maximum error: 18% (E=2J) Minimum error: 1,8% (E=20J)

12. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates

13. Numerical Model Used in Ballistic Impact Model The Lagrange processor was used for projectile and target Uniform cells of side 0.4 mm were used in the central impact area Degenerate cells eroded at an Instantaneous geometric strain 1.0 Interaction: impact-slide logic with a gap size 0.014mm Target: Square Kevlar29/Epoxy plate, 100x100x2mm Projectile: STEEL 4340, STANAG-2920

14. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates Projectile: STANAG-2920, US-MIL-P-46593 5.42 5.30 0.98

15. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates Ballistic Limit: Impact at 320m/s-Total Damage Front view: Experimental vs. Simulation Results Delamination

16. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates Ballistic Limit: Impact at 320m/s-Total Damage Back view: Experimental vs. Simulation Results Eroded NodesFibre Failed

17. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates Ballistic Limit: Simulated Damage Development t=0.0062 ms t=0.0178 ms t=0.0270 ms t=0.0356 mst=0.0399 mst=0.0434 ms Eroded nodes Delamination

18. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates

19. V50: Experiment vs. Simulated Total Damage Delamination Front view: Experimental vs. Simulation Results

20. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates V50: Experiment vs. Simulated Total Damage Back view: Experimental vs. Simulation Results Eroded Nodes Fibre Failed

21. M.A.G. Silva, C. Cismasiu, C.G. Chiorean, Numerical Simulation of Impact on Composite Laminates Simulations of low and high speed impact of composite laminate plate reinforced with Kevlar 29 were performed. Orthotropic constitutive relations coupled with a progressive directional damage model to account for typical damage mechanism of laminates. For low speed impact good corelation between numerical predictions and experimental tests - deflections and impact force. Numerical results stabilised and improved by increased of damping coefficient. For high speed impact good corelation between numerical and experimental tests both in terms of deformation and damage of the laminate and ballistic performance. Conclusions