A numerical simulation method for impact damage and a mapping methodology for damage transfer in adhesively bonded joints
Topic(s) : Special Sessions
Co-authors :
Patrick ERDMANN (GERMANY), Lukas MÜNCH (GERMANY), Mirijam BASTEK , Peter MIDDENDORF , Oliver VOELKERINK (GERMANY)Abstract :
Carbon fibre reinforced plastics (CFRP) are widely used in the aerospace industry. However, the joining of structural components is still a research topic as screws and rivets are mainly used today. Adhesive joints offer an approach where no holes weaken the structure. The lower weight is another benefit due to the absence of rivets leading to lower fuel consumption and consequently lower CO2 emissions. In addition, fewer machining steps are required.
Dealing with CFRP in aerospace application, impact damages play an important role and have to be considered while designing. Tests like the “compression after impact” found their way into standards like the ASTM.
Performing physical tests to prove the damage tolerance of bonded CFRP joints can become quite cost and material intensive. Virtual testing via numerical simulations allows damage tolerance to be analysed early in the development process without the need for costly testing. Thus, numerical simulations are crucial and are used in this study for proving the damage tolerance of bonded joints.
A former study on the development of a numerical method for low velocity impacts on thick composite laminates has shown a good correlation in terms of load-displacement curves and ultrasonic scans [1] for thick laminates. For this simulation method, a stacked shell approach for the laminate to model interlaminar and intralaminar was used.
Aiming at follow-up analysis of the impact analysis like fatigue or residual strength, the resulting impact damage has to be considered as starting condition for these analysis. Additionally, different modelling strategies (e.g. element types and/or routines) were used for follow-up analysis models. Therefore, a mapping strategy to transfer interlaminar, intralaminar and adhesive damages from one simulation to following, enabling different modelling strategies and routines is required and has been mentioned [1] but limited to the transfer between different mesh sizes and only for the transfer of intra- and interlaminar damages.
For this research, the laminate modelling method with ABAQUS/Explicit close to the former study [1] was used and the numerical investigations are extended to bonded structures and validated with a specific laminate thickness. Researches on numerical parameters like mesh size, runtime and application to bigger structures are performed. The results of these investigations are presented.
A mapping strategy to transfer interlaminar, intralaminar and adhesive damages between different models using different modelling strategies and routines is presented. The damage transfer between different models is demonstrated.
The authors acknowledge funding in terms of the JoinDT project from the Federal Ministry for Economic Affairs and Climate Action.
Dealing with CFRP in aerospace application, impact damages play an important role and have to be considered while designing. Tests like the “compression after impact” found their way into standards like the ASTM.
Performing physical tests to prove the damage tolerance of bonded CFRP joints can become quite cost and material intensive. Virtual testing via numerical simulations allows damage tolerance to be analysed early in the development process without the need for costly testing. Thus, numerical simulations are crucial and are used in this study for proving the damage tolerance of bonded joints.
A former study on the development of a numerical method for low velocity impacts on thick composite laminates has shown a good correlation in terms of load-displacement curves and ultrasonic scans [1] for thick laminates. For this simulation method, a stacked shell approach for the laminate to model interlaminar and intralaminar was used.
Aiming at follow-up analysis of the impact analysis like fatigue or residual strength, the resulting impact damage has to be considered as starting condition for these analysis. Additionally, different modelling strategies (e.g. element types and/or routines) were used for follow-up analysis models. Therefore, a mapping strategy to transfer interlaminar, intralaminar and adhesive damages from one simulation to following, enabling different modelling strategies and routines is required and has been mentioned [1] but limited to the transfer between different mesh sizes and only for the transfer of intra- and interlaminar damages.
For this research, the laminate modelling method with ABAQUS/Explicit close to the former study [1] was used and the numerical investigations are extended to bonded structures and validated with a specific laminate thickness. Researches on numerical parameters like mesh size, runtime and application to bigger structures are performed. The results of these investigations are presented.
A mapping strategy to transfer interlaminar, intralaminar and adhesive damages between different models using different modelling strategies and routines is presented. The damage transfer between different models is demonstrated.
The authors acknowledge funding in terms of the JoinDT project from the Federal Ministry for Economic Affairs and Climate Action.