PSI - Issue 60

ScienceDirect Structural Integrity Procedia 00 (2024) 000–000 Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2024) 000–000 Available online at www.sciencedirect.com ScienceDirect

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

Procedia Structural Integrity 60 (2024) 517–524

2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the ICONS 2023 Organizers 10.1016/j.prostr.2024.05.071 2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license ( https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the ICONS 2023 Organizers Fiber reinforced composite materials are widely used in many engineering fields such as aircraft, marine, automotive and civil due to its light weight, high specific stiffness and high specific strength. The laminated composites are designed to prevent failure; they exhibit a brittle failure mode with matrix cracking and delamination failure mode under static or dynamic loading conditions. The composite structure may undergo various types of loading including mild to severe impact loading during its service life. The impact velocity range depends on material, geometry and thickness of the laminate, mass and shape of the impactor. Generally, it can be classified into four categories: low velocity (large mass) impact (<10 m/s), intermediate impact (10 m/s to 50 m/s), high velocity (small mass) impact (50 m/s to 1000 m/s) and hyper velocity impact (2000 m/s to 5000 m/s). The damage mechanisms of composite structures are different for high and low velocity impact loading. For high velocity impact loading, such as, bullet impact and bird-strike, perforation in a short duration is more predominant [Ismail et al (2019)]. ∗ Corresponding author. E-mail address: me19d018@smail.iitm.ac.in; raghuprakash@iitm.ac.in. ∗ 2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license ( https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the ICONS 2023 Organizers Abstract The impact response and failure mechanism of carbon fiber reinforced composite laminates under low velocity impact was investigated using ABAQUS®. A finite element model was developed based on the progressive damage theory to study the impact response of CFRP laminates with hemispherical impactor. The impact tests were conducted on cross-ply (0/90) 2s and quasi-isotropic, QI (0/45/-45/90) s laminates with different impact velocities. From the numerical simulation, the damage initiation and propagation in the CFRP laminates were found in terms of damage location, size and shape. The intra-laminar damages such as fiber and matrix damages were predicted using in-built Hashin criterion of ABAQUS®. The traction separation based cohesive surface modelling approach was utilized for capturing the inter-laminar failure initiation and propagation induced by impact loading. The numerical results of different impact energy levels were analysed for different failure modes for varying impact force, displacement and kinetic energy. The total volume of fiber damage and the total area of delamination were calculated for each laminate sequence. From numerical simulations, it was observed that the delamination was less on cohesive surfaces above the mid-thickness plane due to high compression through the thickness. The fiber damage was found at 65 J of impact energy. The first load drop was observed in the cross-ply laminates due to the delamination between lamina 5 and 6. The study revealed that the QI laminates had higher impact resistance and smaller damage zone than the cross-ply laminates. © 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the ICONS 2023 Organizers. Keywords: Cohesive surface-based contact; Delamination; Hashin criterion; Fiber damage; Matrix damage. 1. Introduction Fiber reinforced composite materials are widely used in many engineering fields such as aircraft, marine, automotive and civil due to its light weight, high specific stiffness and high specific strength. The laminated composites are designed to prevent failure; they exhibit a brittle failure mode with matrix cracking and delamination failure mode under static or dynamic loading conditions. The composite structure may undergo various types of loading including mild to severe impact loading during its service life. The impact velocity range depends on material, geometry and thickness of the laminate, mass and shape of the impactor. Generally, it can be classified into four categories: low velocity (large mass) impact (<10 m/s), intermediate impact (10 m/s to 50 m/s), high velocity (small mass) impact (50 m/s to 1000 m/s) and hyper velocity impact (2000 m/s to 5000 m/s). The damage mechanisms of composite structures are different for high and low velocity impact loading. For high velocity impact loading, such as, bullet impact and bird-strike, perforation in a short duration is more predominant [Ismail et al (2019)]. ∗ Corresponding author. E-mail address: me19d018@smail.iitm.ac.in; raghuprakash@iitm.ac.in. © 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the ICONS 2023 Organizers Abstract The impact response and failure mechanism of carbon fiber reinforced composite laminates under low velocity impact was investigated using ABAQUS®. A finite element model was developed based on the progressive damage theory to study the impact response of CFRP laminates with hemispherical impactor. The impact tests were conducted on cross-ply (0/90) 2s and quasi-isotropic, QI (0/45/-45/90) s laminates with different impact velocities. From the numerical simulation, the damage initiation and propagation in the CFRP laminates were found in terms of damage location, size and shape. The intra-laminar damages such as fiber and matrix damages were predicted using in-built Hashin criterion of ABAQUS®. The traction separation based cohesive surface modelling approach was utilized for capturing the inter-laminar failure initiation and propagation induced by impact loading. The numerical results of different impact energy levels were analysed for different failure modes for varying impact force, displacement and kinetic energy. The total volume of fiber damage and the total area of delamination were calculated for each laminate sequence. From numerical simulations, it was observed that the delamination was less on cohesive surfaces above the mid-thickness plane due to high compression through the thickness. The fiber damage was found at 65 J of impact energy. The first load drop was observed in the cross-ply laminates due to the delamination between lamina 5 and 6. The study revealed that the QI laminates had higher impact resistance and smaller damage zone than the cross-ply laminates. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the ICONS 2023 Organizers. Keywords: Cohesive surface-based contact; Delamination; Hashin criterion; Fiber damage; Matrix damage. 1. Introduction 2s s Third International Conference on Structural Integrity 2023 (ICONS 2023) Numerical investigation of the low velocity impact behavior of CFRP laminates Rajagurunathan, M a , Raghu V. Prakash b* a b* Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai-600036, India Third International Conference on Structural Integrity 2023 (ICONS 2023) Numerical investigation of the low velocity impact behavior of CFRP laminates Rajagurunathan, M a , Raghu V. Prakash b* a Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai-600036, India b* Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai-600036, India a b*