Multiphysics Simulation of Additive Manufacturing-Induced Fracture Mechanics using Peridynamic Theory

Presentation link

Jan-Timo HesseORCID Symbol, Christian WillbergORCID Symbol, Felix Winkelmann, Robert HeinORCID Symbol

18th International Conference on Computational Plasticity - COMPLAS 2025
2-5 September, 2025 - Barcelona

Presentation URL: https://perihub.github.io/Presentations/COMPLAS_2025
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Introduction 3D printing

- Additive extrusion processes enables manufacturing of complex structures without moulds

  • Many process parameters influence the final properties

    • Individual process parameter - property relation often unclear

  • Process simulations can help to predict the properties and evaluate the process parameters

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Introduction polymer crystallization

- Crystallization influences the mechanical and technical properties of the material

  • Degree of crystallization depends on material properties and cooling conditions

  • Complex processes during cooling in deposition processes

Figure Source: Yang et al., Influence of thermal processing conditions in 3D printing ...
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Subroutine

  • Calculation of crystallization, dual kinetic model (by Velisaris & Seferis)

  • Implementation in Fortran HETVAL Subroutine for usage in Abaqus

    • Calculates crystallization kinetics through process simulation
    • Degree of crystallization at every time step

  • Temperature and time from the process simualtion are inputs for the subroutine

  • Stiffness value of each node will be adapted based on the degree of crystallization

  • Fitting function:

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Simulation

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What is Peridynamics?

  • Alternative to classcical continuum mechanics:
  • PD integral equation:
  • Focus material modeling and crack propagation; no continuity for the displacement
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PD Solving the integral - Material point method

Advantages

  • Fast to implement
  • Failure propagation
  • Discretization

Diadvantages

  • Convergence is lower
  • Surfaces are not known
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Peridynamic Framework (PeriLab)

  • No pre-processing required, mesh will be generated based on the gcode
  • Material Models:
    • PD Solid Elastic/Plastic
  • Thermal Models:
    • Thermal Flow
    • Heat Transfer
    • HETVAL subroutine
  • Damage Models:
    • Critical Stretch

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Dogbone Specimen

  • Three step simulation process:
    • Printing specimen
    • Cooling step
    • Tensile test
  • Layer height = 0.2mm (20 Layers)
Specimen Geometry: ASTM D638
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Simulation Properties

Material: PEEK (Polyetheretherketon)

Parameter Value

Thermal Properties

Parameter Value

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Simulation Results

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Simulation Results


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Simulation Results

  • Crack initiation and propagation simliar, only initiation time slightly differs
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Load-Displacement

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Discussion and further work

  • Basic influence of different process parameters can be captured

  • PeriLab allows efficient and statistical analysis of the AM process

  • Verification with experiments

  • Variation of diverse process parameters

  • Influence of printbed

Thank you!

Jan-Timo Hesse (DLR)
Christian Willberg (h2)
Felix Winkelmann (DLR)
Robert Hein (DLR)

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References

  1. J. Shah, B. Snider, T. Clarke, S. Kozutsky, M. Lacki & A. Hosseini (2019). Large-scale 3D printers for additive manufacturing: design considerations and challenges.
  2. C. Yang, X. Tian, D. Li, Y. Cao, F. Zhao & C. Shi (2017). Influence of thermal processing conditions in 3D printing on the crystallinity and mechanical properties of PEEK material.
  3. C. Willberg, J-T. Hesse, R. Hein & F. Winkelmann (2024). Peridynamic Framework to Model Additive Manufacturing Processes.
  4. C. Willberg, J-T. Hesse & A. Pernatii (2024). PeriLab - Peridynamic Laboratory.

Funding

Name Logo Grant number
German Research Foundation WI 4835/5-1
Saxon State Parliament 3028223
Federal Ministry for Economic Affairs and Climate Action 20W2214G