DOI: 10.5281/zenodo.17035635
title: Reactive coarse-grained MD models to capture interphase formation in  epoxy-based structural adhesive joints - dataset

description:  

Abstract:from [1]

Adhesive joints offer a superior strength-to-weight ratio compared to conventional fastening methods, making them essential for achieving cost-efficiency and sustainability goals. The adherends influence the adhesive in their immediate vicinity, creating regions with altered microstructures. These regions, known as interphases, exhibit material properties that differ from those of the bulk adhesive and are not fully understood from an engineering perspective.To address this issue, we introduce a novel coarse-grained molecular dynamics (CGMD) model for adhesive joints, which aims to study the interphase formation and its resulting properties at the molecular level.  We utilize a reactive epoxy model from the literature for the adhesive and implement matching aluminium substrates, along with the necessary adherend-adhesive interaction parameters.  The resulting adhesive joint model allows us to investigate the formation of the adhesive's microstructure during the curing process and the mechanical properties of the joint.  We conduct a parameter study on the adherend-adhesive interaction parameters, unravel the role of grafting bonds and their distribution, and examine the impact of the adhesive's thickness. Additionally, we identify an interphase based on variations in the local microstructure, estimate its size, and determine the influencing parameters.  In this first contribution, we demonstrate the capabilities of our model in evaluating the mechanical behavior of the interphase, which is crucial for gaining a better understanding of adhesive joints.

Contact:

Maximilian RiesInstitute of Applied MechanicsFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 591058 Erlangen

Software:

All MD simulations were performed with LAMMPS [2,3], version: 2 Aug 2023 - Update 3, with REACT package [4,5]

Compiled withCompiler: GNU C++ 11.2.0 with OpenMP not enabledC++ standard: C++11

Post-processing Matlab R2023b

License:

Creative Commons Attribution 4.0 International

Context:

Data set supplementing  journal paper:[1] V. Dötschel, E. M. Richter, G. Possart, P. Steinmann, M. Ries,  "Reactive coarse-grained MD models to capture interphase formation in epoxy-based structural adhesive joints." European Journal of Mechanics-A/Solids (2025): 105801.

Content:

structure of data set (follows sections of [1]):

    - 3.1 Adherend-adhesive interaction parameters    - 3.2.1 Grafting bond density    - 3.2.2 Grafting bond heterogeneities    - 3.3 Adhesive layer thickness    - A2 Case III: no grafting

       

naming convention for simulation folders

    - case_I, case_II, case_III:     refers to the different force field parameter sets discussed in the paper    - surf_react:                    gives the grafting density in percent    - hole05:                        indicates an inert region of 50percent    - EQ:                            contains equilibration files    - UT:                             contains uniaxial tensile files    - _double, _half:                indicates the adhesive joint thickness, double or half of the standard presented in 3.1    - _01 to _05:                    number of the replica    - bins

 

Each simulation directory contains:

    data files (*.data) containing the sample configuration in LAMMPS data format    dat files (*.dat)   containing simulation output, format explained below

    LAMMPS_out:            simulation results                 - ReadyForCuring.data                            sample configuration directly before curing        - Sandwich_Sim_Curing1.data                        sample configuration after curing stage I        - Sandwich_Sim_Curing2.data                        sample configuration after curing stage II        - Sandwich_Sim_Curing3.data                        sample configuration after curing stage III        - Sandwich_Sim_Curing4.data                        sample configuration after curing stage IV (end of curing)        - Sandwich_Sim_finalEquil_afterBC_change.data    sample at end of equilibration, i.e., ready for deformation        - Sandwich_Sim_afterDeformation.data            sample after deformation                - thermo.dat                                    tabulated thermodynamic output during equilibration in columns, containing            TimeStep                     timestep            c_thermo_temp                 temperature in K            c_thermo_press[1]             pressure component pxx in atm            c_thermo_press[2]             pressure component pyy in atm                 c_thermo_press[3]             pressure component pzz in atm             c_thermo_press[4]             pressure component pxy in atm             c_thermo_press[5]             pressure component pxz in atm             c_thermo_press[6]             pressure component pyz in atm             v_PACM_react                 fraction of reacted PACM (linear and network reactions)            v_DC                         fraction of reacted DGEBA excluding grafting reactions            v_DGEBA_react                 fraction of reacted DGEBA including grafting reactions            v_Surf_react                 fraction of reacted substrate surface atoms            v_Etot                         total energy in kcal/mol            v_Epair                     nonbonded energy in kcal/mol            v_Ebond                     bond energy in kcal/mol            v_Eangle                     angle energy in kcal/mol            v_Epot                         potential energy in kcal/mol            v_Ekin                         kinetic energy in kcal/mol            v_Stress_xx_MPa             stress component in xx direction in MPa            v_Density                     density of simulation box in g/cm^3            v_Lx                         length of simulation box in x direction            v_Ly                         length of simulation box in y direction            v_Lz                         length of simulation box in z direction            v_Stress_yy_MPa             stress component in yy direction in MPa             v_Stress_zz_MPa             stress component in zz direction in MPa             v_Stress_xy_MPa             stress component in xy direction in MPa             v_Stress_xz_MPa             stress component in xz direction in MPa             v_Stress_yz_MPa             stress component in yz direction in MPa                - thermo_UT.dat                             tabulated thermodynamic output during deformation in columns, containting             TimeStep                     timestep            c_thermo_temp                 temperature in K            c_thermo_press[1]             pressure component pxx in atm            c_thermo_press[2]             pressure component pyy in atm                 c_thermo_press[3]             pressure component pzz in atm             c_thermo_press[4]             pressure component pxy in atm             c_thermo_press[5]             pressure component pxz in atm             c_thermo_press[6]             pressure component pyz in atm             v_Etot                         total energy in kcal/mol            v_Epair                     nonbonded energy in kcal/mol            v_Ebond                     bond energy in kcal/mol            v_Eangle                     angle energy in kcal/mol            v_Epot                         potential energy in kcal/mol            v_Ekin                         kinetic energy in kcal/mol            v_Stress_xx_MPa             stress component in xx direction in MPa            v_Density                     density of simulation box in g/cm^3            v_Lx                         length of simulation box in x direction            v_Ly                         length of simulation box in y direction            v_Lz                         length of simulation box in z direction            v_Strain_xx                 strain component in xx direction            v_Strain_yy                  strain component in yy direction            v_Strain_zz                  strain component in zz direction            v_Strain_xy                  strain component in xy direction            v_Strain_xz                  strain component in xz direction            v_Strain_yz                  strain component in yz direction            v_Stress_xx_MPa                 stress component in xx direction in MPa            v_Stress_yy_MPa                 stress component in yy direction in MPa            v_Stress_zz_MPa                 stress component in zz direction in MPa            v_Stress_xy_MPa                 stress component in xy direction in MPa            v_Stress_xz_MPa                 stress component in xz direction in MPa            v_Stress_yz_MPa                 stress component in yz direction in MPa            v_Volume_Epoxy1                 polymer volume via substrate volume in A^3            v_Volume_Epoxy2                 polymer volume via box lenghts in A^3            v_Cauchy_xx_MPa_Epoxy1             stress component in xx direction in MPa with respect to Volume_Epoxy1 (only polymer)            v_Cauchy_yy_MPa_Epoxy1             stress component in yy direction in MPa with respect to Volume_Epoxy1 (only polymer)            v_Cauchy_zz_MPa_Epoxy1             stress component in zz direction in MPa with respect to Volume_Epoxy1 (only polymer)            v_Cauchy_xy_MPa_Epoxy1             stress component in xy direction in MPa with respect to Volume_Epoxy1 (only polymer)            v_Cauchy_xz_MPa_Epoxy1             stress component in xz direction in MPa with respect to Volume_Epoxy1 (only polymer)            v_Cauchy_yz_MPa_Epoxy1             stress component in yz direction in MPa with respect to Volume_Epoxy1 (only polymer)            c_ForceLeft                     resulting force acting on left substrate in kcal/(mol A)            c_ForceRight                     resulting force acting on right substrate in kcal/(mol A)            c_ForceBothSurfaces             resulting force acting on both substrates in kcal/(mol A)            v_NominalStressLeft             nominal tensile stress via force acting on left substrate in MPa            v_NominalStressRight             nominal tensile stress via force acting on right substrate in MPa            v_TrueStressLeft                 true tensile stress via force acting on left substrate in MPa                v_TrueStressRight                 true tensile stress via force acting on left substrate in MPa            v_Cauchy_xx_MPa_Epoxy2             stress component in xx direction in MPa with respect to Volume_Epoxy2 (only polymer)            v_Cauchy_yy_MPa_Epoxy2             stress component in yy direction in MPa with respect to Volume_Epoxy2 (only polymer)            v_Cauchy_zz_MPa_Epoxy2             stress component in zz direction in MPa with respect to Volume_Epoxy2 (only polymer)            v_Cauchy_xy_MPa_Epoxy2             stress component in xy direction in MPa with respect to Volume_Epoxy2 (only polymer)            v_Cauchy_xz_MPa_Epoxy2             stress component in xz direction in MPa with respect to Volume_Epoxy2 (only polymer)            v_Cauchy_yz_MPa_Epoxy2            stress component in yz direction in MPa with respect to Volume_Epoxy2 (only polymer)                - Bins*.dat                         output for spatial binning of atom type *, i.e, 3, 5, 8, 9, 10, or 11; containing                Chunk                            ID for ith binning            Coord1                            center coordinate of binning            Ncount                            number of atom of atom type * in current bin            density/number                    number density of atom type * in current bin                

References:

[1] V. Dötschel, E. M. Richter, G. Possart, P. Steinmann, M. Ries,  "Reactive coarse-grained MD models to capture interphase formation in epoxy-based structural adhesive joints." European Journal of Mechanics-A/Solids (2025): 105801.

[2] S. Plimpton, “Fast parallel algorithms for short-range molecular dynamics,” Journal of computational physics, 1995, 117, 1-19.

[3] A. P. Thompson et al., “LAMMPS - a flexible simulation tool for particle-based materials modeling at the atomic, meso, and continuum scales,” Computer Physics Communications, vol. 271, p. 108171, 2022.

[4] J. R. Gissinger, B. D. Jensen, and K. E. Wise, “Modeling chemical reactions in classical molecular dynamics simulations,” Polymer, vol. 128, pp. 211–217, 2017.

[5] J. R. Gissinger, B. D. Jensen, and K. E. Wise, “Reacter: A heuristic method for reactive molecular dynamics,” Macromolecules, vol. 53, no. 22, pp. 9953–9961, 2020.