Master Thesis, 30 HP: Material Modelling of Carbon Fiber Reinforced Polymer for Low-Velocity Impact in Ansys LS-DYNA

Are you a student eager to apply your theoretical knowledge and fresh perspectives to real-world challenges? At Saab, we believe that innovation thrives on new ideas, and your master thesis project could be the spark that ignites our next technological breakthrough.

Your role

We recognize the immense value that students bring to our company. Your academic rigor, combined with your enthusiasm for cutting-edge technology, allows you to approach problems with a unique and insightful lens. At Saab, you'll have the opportunity to collaborate with experienced engineers and specialists, gaining invaluable practical experience while making a tangible contribution to our growth and development.

This master thesis will be carried out within the Structural Analysis division at Saab Dynamics, Business Unit Ground Combat, with placement in Karlstad/Karlskoga. One site will be your primary location, with occasional travel to the other site when necessary.

Background

Carbon fiber reinforced polymers (CFRPs) offer high specific strength and stiffness, making them attractive for lightweight structures with demanding performance requirements. However, their mechanical response and failure behavior are considerably more complex than those of conventional metallic materials.

When subjected to low-velocity impact, composite laminates may develop interacting damage mechanisms, including matrix cracking, fiber failure, delamination, crushing, and permanent deformation. Some damage can occur internally and be difficult to detect through external inspection while still causing a significant reduction in structural performance.

Predicting such damage using finite element analysis requires suitable material models, representative material parameters, appropriate element and contact formulations, and reliable calibration and validation methods.

Ansys LS-DYNA provides several material models for fiber-reinforced composites. These differ in theoretical assumptions, required material data, damage and failure representation, numerical robustness, computational cost, and suitability for different element formulations and applications. Selecting an appropriate model and determining its parameters can therefore be challenging.

For Saab Dynamics, it is of interest to establish a structured understanding of how available composite material models in Ansys LS-DYNA can be applied to simulate low-velocity impact damage in carbon fiber reinforced polymer structures.

Description of the master thesis
The purpose of this thesis is to take a first step towards being able to predict damage and failure in a CFRP laminate subjected to a low-velocity impact drop test. The thesis will primarily be theoretically and numerically focused. Physical material testing or impact testing is unlikely to be included within the thesis itself.

The aim of this thesis is to develop a structured methodology for material modelling of carbon fiber reinforced polymer under low-velocity impact loading in Ansys LS-DYNA.

The work should investigate available modelling approaches and establish the material data, calibration procedures, and validation methods required to represent relevant damage and failure mechanisms.

The thesis may include:

• Literature review of damage and failure mechanisms in carbon fiber reinforced polymer laminates subjected to low-velocity impact.
• Review, comparison, and evaluation of relevant composite material models available in Ansys LS-DYNA, including their theoretical assumptions, capabilities, limitations, intended applications, and required material parameters.
• Assessment of material-data requirements, including which parameters can be obtained from standard material tests, which require inverse calibration, and which may be estimated from literature or supplier data, as well as proposal of suitable material tests and specimen geometries.
• Definition of a stepwise workflow for material-model calibration, optimization, and validation, including investigation of objective functions, response quantities, and optimization strategies for inverse parameter identification.
• Proposal and setup of a representative low-velocity impact validation case, such as a numerical drop-weight impact test on a composite laminate.
• Investigation of relevant modelling aspects, including element formulations, laminate representation, damage and delamination modelling, contact definitions, mesh sensitivity, damage regularization, numerical stability, and computational cost.
• Evaluation of the selected material models with respect to damage representation, material-data requirements, calibration effort, numerical robustness, computational cost, mesh sensitivity, suitability for low-velocity impact simulations, and future industrial applications.
• Pre-processing, model preparation, and post-processing using Ansys Discovery, Ansys Mechanical, LS-PrePost, and scripting in Python or MATLAB.

The validation case should be used to demonstrate the proposed workflow and investigate which simulation outputs are suitable for comparison with experimental data. Relevant output quantities may include impact force, impactor displacement, absorbed energy, force-time history, force-displacement response, damaged area, failure mode, delamination pattern, and residual deformation.

Since physical testing is unlikely to be performed within the thesis, published experimental results, available internal data, representative literature data, or a combination of these may be used to support the numerical investigation. The emphasis will be on establishing a technically sound methodology and determining what material data and physical tests would be required for future predictive simulations.

The thesis should result in a structured assessment of material-modelling approaches for CFRP under low-velocity impact loading in Ansys LS-DYNA. It should also provide practical recommendations for model selection, material characterization, parameter calibration, numerical implementation, and future validation work within Saab Dynamics.

The final scope can be adapted depending on the student’s background, interests, available material data, and available software functionality.

Your profile

This master thesis is suitable for one or two students studying Mechanical Engineering, Engineering Physics, Applied Mechanics, Materials Engineering, or a similar program.

You are approaching the end of your master’s studies and plan to start your thesis work during spring 2027. The thesis corresponds to 30 hp.

You have an interest in composite materials, material modelling, finite element analysis, and structural mechanics. Previous experience with the finite element method or composite mechanics is beneficial, but not mandatory.

Experience or interest in the following areas is valuable:

• Finite element analysis, composite materials and laminate theory.
• Material damage and failure modelling, impact dynamics.
• Experimental mechanics and material testing.
• Ansys LS-DYNA or similar explicit finite element solvers.
• Numerical optimization and parameter identification.
• Python or MATLAB scripting.

You should be comfortable working independently with theoretical material, technical documentation, numerical models, and simulation results. An analytical and systematic approach will be important, particularly when comparing material models and defining a traceable calibration methodology.

You may apply individually or together with another student. If you prefer to perform the thesis together with someone, please state this in your application and include the name of the other student.

This position requires that you pass a security vetting based on current regulations concerning security protection. For positions requiring security clearance, additional obligations regarding citizenship may apply.

Kindly observe that this is an ongoing recruitment process and that the position may be filled before the closing date of the advertisement.

Contact information

Robin Heimonen
Email: robin.heimonen@saabgroup.com
Phone: +46 102173103

Oskar Norman
Email: oskar.norman@saabgroup.com
Phone: +46 10 – 27 89 124

What you will be a part of

Explore a wealth of possibilities. Take on challenges, create smart inventions, and grow beyond. This is a place for curious minds, brave pioneers, and everyone in between. Together, we achieve the extraordinary, each bringing our unique perspectives. Your part matters.

Saab is a leading defense and security company with an enduring purpose, to help nations keep their people and society safe. Empowered by its 28,000 talented people, Saab constantly pushes the boundaries of technology to create a safer and more sustainable world.

Saab designs, manufactures and maintains advanced systems in aeronautics, weapons, command and control, sensors and underwater systems. Saab is headquartered in Sweden. It has major operations all over the world and is part of the domestic defense capability of several nations. Read more about us here.