PUBLICATIONS

Please contact the authors if you would like to receive a reprint of any of our articles. Your interest in our research is highly appreciated. We are more than happy to send you electronic files of any of the papers. 

2017

1Pekala, P. A. and Henry, B. M. and Ochala, A. and Kopacz, P. and Taton, G. and Mlyniec, A. and Walocha, J. A. and Tomaszewski, K. A., "The twisted structure of the Achilles tendon unraveled: A detailed quantitative and qualitative anatomical investigation", Scandinavian Journal of Medicine and Science in Sports, 27 , 1705--1715, 2017 Link BIB
@article{Pekala2017,
author = {Pekala, P. A. and Henry, B. M. and Ochala, A. and Kopacz, P. and Taton, G. and Mlyniec, A. and Walocha, J. A. and Tomaszewski, K. A.},
doi = {10.1111/sms.12835},
file = {:Users/andrzejmlyniec/Library/Application Support/Mendeley Desktop/Downloaded/Pekala et al. - 2017 - The twisted structure of the Achilles tendon unraveled A detailed quantitative and qualitative anatomical investi.pdf:pdf},
issn = {16000838},
journal = {Scandinavian Journal of Medicine and Science in Sports},
keywords = {3D structure,Anatomy,Biomechanics,Calcaneal tendon,Subtendons},
pages = {1705--1715},
title = {{The twisted structure of the Achilles tendon unraveled: A detailed quantitative and qualitative anatomical investigation}},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/sms.12835},
volume = {27},
year = {2017},
abstract = {The Achilles tendon (AT) consists of fibers originating from the soleus muscle (SOL), which lies deep, and the medial (GM) and lateral (GL) heads of the gastroc-nemius muscle, which lie superficial. As the fibers descend toward the insertion of the AT, the individual subtendons twist around each other. The aim of this study was to investigate the twisted structure of the AT and its individual subtendons. Specimens of the AT, with preserved calcaneal bone and a fragment of the triceps surae muscle, were obtained from 53 fresh-frozen, male cadavers (n=106 lower limbs). The angle of torsion of each of the AT's subtendons was measured using a specially designed and 3D-printed tool. The mean distance between the most distal fibers of the triceps surae muscle and the superior border of the calcaneal bone was 60.77±14.15 mm. The largest component of the AT at the level of its insertion into the calcaneal bone is the subtendon from the GL (44.43\%), followed by the subtendon from SOL (27.89\%), and the subtendon from GM (27.68\%). The fibers originating from the GM rotate on average 28.17±15.15°, while the fibers originating from the GL and SOL twist 135.98±33.58° and 128.58±29.63°, respectively. The torsion of superficial fib-ers (GM) comprising the AT is significantly lower than that of deeper fibers (GL and SOL). The cross-sectional area of the AT is smaller at the level of the musculo-tendinous junction than at the level of its insertion. This study illustrates the three types of the AT with differently twisting subtendons, as well as a generalized model of the AT. Types of AT torsion may potentially alter the biomechanical properties of the tendon, thus possibly influencing the pathophysiologic mechanisms leading to the development of various tendinopathies.},
isbn = {09057188 (ISSN)},
pmid = {28139009}
}

2016

1Mlyniec, A. and Korta, J. and Uhl, T., "Structurally based constitutive model of epoxy adhesives incorporating the influence of post-curing and thermolysis", Composites Part B: Engineering, 86 , 160--167, 2016 Link BIB
@article{Mlyniec2016a,
author = {Mlyniec, A. and Korta, J. and Uhl, T.},
doi = {10.1016/j.compositesb.2015.09.062},
issn = {13598368},
journal = {Composites Part B: Engineering},
pages = {160--167},
title = {{Structurally based constitutive model of epoxy adhesives incorporating the influence of post-curing and thermolysis}},
url = {http://linkinghub.elsevier.com/retrieve/pii/S1359836815006265},
volume = {86},
year = {2016},
abstract = {Performance of the adhesively joined composite structures frequently depends on their stiffness since excessive deformation can alter their functionality. In this article, we present the structurally based constitutive model which takes into account the influence of the post-curing as well as thermolysis process on stiffness of epoxy adhesives. We propose the chemomechanical model considering the autocatalytic post-curing process and thermolysis, which dominates in the first phase of the degradation process at elevated temperatures. The proposed model employs reaction kinetics of curing and ther- molysis of epoxy, statistical mechanics as well as non-linear large strain constitutive material model which incorporates influence of chemical reactions. Presented model is calibrated to the results of experimental investigations probing the influence of the aging cycles according to the SAE/USCAR standard on stiffness of the epoxy adhesives. The material model is validated by comparison with results of single lap shear tests after HumidityeTemperature aging in class I and V.We achieve 98.3\% compliance for investigated aging cycles. Proposed model takes into account not only aging effects but elevated temperatures as well. Thus it can be used for prediction of the mechanical behavior of heavy loaded epoxy adhesive joints working in engine compartment. The consistency of the experimental results with model predictions, proves that our chemomechanical model constitutes a useful tool for the prediction of the durability and lifetime of adhesively joined structures.},
publisher = {Elsevier Ltd}
}
2Mlyniec, Andrzej and Ekiert, Martyna and Morawska-Chochol, Anna and Uhl, Tadeusz, "Influence of density and environmental factors on decomposition kinetics of amorphous polylactide - Reactive molecular dynamics studies", Journal of Molecular Graphics and Modelling, 67 , 54--61, 2016 Link BIB
@article{Mlyniec2016b,
author = {Mlyniec, Andrzej and Ekiert, Martyna and Morawska-Chochol, Anna and Uhl, Tadeusz},
doi = {10.1016/j.jmgm.2016.04.010},
issn = {10933263},
journal = {Journal of Molecular Graphics and Modelling},
pages = {54--61},
title = {{Influence of density and environmental factors on decomposition kinetics of amorphous polylactide - Reactive molecular dynamics studies}},
url = {http://dx.doi.org/10.1016/j.jmgm.2016.04.010},
volume = {67},
year = {2016},
publisher = {Elsevier Inc.}
}

2015

1Mlyniec, Andrzej and Mazur, Lukasz and Tomaszewski A, Krzysztof and Uhl, Tadeusz, "Viscoelasticity and failure of collagen nanofibrils: 3D Coarse-Grained simulation studies", Soft Materials, 13 1, 47--58, 2015 Link BIB
@article{Mlyniec2015a,
author = {Mlyniec, Andrzej and Mazur, Lukasz and Tomaszewski A, Krzysztof and Uhl, Tadeusz},
doi = {10.1080/1539445X.2015.1009549},
journal = {Soft Materials},
number = {1},
pages = {47--58},
title = {{Viscoelasticity and failure of collagen nanofibrils: 3D Coarse-Grained simulation studies}},
url = {http://www.tandfonline.com/doi/abs/10.1080/1539445X.2015.1009549},
volume = {13},
year = {2015},
abstract = {In this manuscript, we investigate the influence of loading rate and fibril length on viscoelastic and failure behavior of collagen nanofibrils. The computational experiments were performed using three-dimensional shape-based Coarse-Grained models of collagen nanofibrils, with parameters derived from atomistic simulations. The atomistic computational tensile and shear experiments were performed using Molecular Dynamics and extended AMBER force field for aqueous and non-aqueous environments. The Coarse-Grained interactions were defined by both intermolecular and intramolecular potentials which describe non-bonded and bonded interactions respectively. Computational studies revealed that the hydrogen bond network impacts both viscoelastic behavior and failure of collagen nanofibrils. Greater fibril length results in brittle cracking while higher loading rates result in ductile behavior, due to the unwinding and sliding of the fibril. The proposed Coarse-Grained model can be used in further studies incorporating the effects of ageing, such as collagen degradation and glycation.}
}
2Mlyniec, A. and Tomaszewski, K.A. and Spiesz, E.M. and Uhl, T., "Molecular-based nonlinear viscoelastic chemomechanical model incorporating thermal denaturation kinetics of collagen fibrous biomaterials", Polymer Degradation and Stability, 119 , 87--95, 2015 Link BIB
@article{Mlyniec2015b,
author = {Mlyniec, A. and Tomaszewski, K.A. and Spiesz, E.M. and Uhl, T.},
doi = {10.1016/j.polymdegradstab.2015.05.005},
issn = {01413910},
journal = {Polymer Degradation and Stability},
keywords = {chemomechanical model,collagen denaturation,collagen microfibrils},
pages = {87--95},
title = {{Molecular-based nonlinear viscoelastic chemomechanical model incorporating thermal denaturation kinetics of collagen fibrous biomaterials}},
url = {http://linkinghub.elsevier.com/retrieve/pii/S0141391015001731},
volume = {119},
year = {2015},
publisher = {Elsevier Ltd}
}
3Korta, Jakub and Mlyniec, Andrzej and Uhl, Tadeusz, "Experimental and numerical study on the effect of humidity-temperature cycling on structural multi-material adhesive joints", Composites Part B: Engineering, 79 , 621--630, 2015 Link BIB
@article{Korta2015,
author = {Korta, Jakub and Mlyniec, Andrzej and Uhl, Tadeusz},
doi = {10.1016/j.compositesb.2015.05.020},
journal = {Composites Part B: Engineering},
keywords = {adhesion,environmental degradation,joining,joints,mechanical,multi-material,testing},
pages = {621--630},
title = {{Experimental and numerical study on the effect of humidity-temperature cycling on structural multi-material adhesive joints}},
url = {http://linkinghub.elsevier.com/retrieve/pii/S1359836815003248},
volume = {79},
year = {2015},
abstract = {The following paper describes investigations on the impact of harsh environment on shear and tensile strength of multi-material adhesive joints. The samples were made from carbon fiber epoxy composites, aluminum and two types of advanced steels: abrasion resistant and high-strength. In order to assess the suitability of structural bonding for this sort of applications, it was decided to test two different epoxy-based adhesives, designed for moderate and elevated operating temperatures. The harmful conditions were simulated by means of humidity-temperature cycling tests, according to the SAE standard. The obtained results revealed that even moderately harsh humidity-temperature loads can cause debonding of the joints, even if no external forces are applied. In order to gain insight into this phenomenon, a series of finite element analyses was performed, simulating the exposure of the samples to the chosen environmental conditions. Based on these studies, the temperature expansion coefficient was identified as the crucial factor for the performance of the joints made from dissimilar materials. The results of the described experiments, confirmed by numerical calculations, constitute a guideline for multi-material structural design, supporting this constantly growing branch of modern engineering with a relevant input.},
publisher = {Elsevier Ltd}
}

2014

1Mlyniec, A. and Korta, J. and Kudelski, R. and Uhl, T., "The influence of the laminate thickness, stacking sequence and thermal aging on the static and dynamic behavior of carbon/epoxy composites", Compos. Struct., 118 , 208--216, 2014 Link BIB
@article{Mlyniec2014c,
author = {Mlyniec, A. and Korta, J. and Kudelski, R. and Uhl, T.},
doi = {10.1016/j.compstruct.2014.07.047},
issn = {02638223},
journal = {Compos. Struct.},
keywords = {Damping factors,Durability,Environmental degradation,Polymer-matrix composites,Thermal aging,Vibration},
month = aug,
pages = {208--216},
title = {{The influence of the laminate thickness, stacking sequence and thermal aging on the static and dynamic behavior of carbon/epoxy composites}},
url = {http://www.sciencedirect.com/science/article/pii/S0263822314003705},
volume = {118},
year = {2014},
abstract = {In this work, we investigate the influence of laminate thickness, stacking sequence and thermal aging on the damping behavior of carbon/epoxy laminates. The dynamic behavior of quasi-isotropic and unidirectional laminates of different thickness, are measured by means of Laser Doppler Vibrometry and Dynamic Mechanical Analysis. Obtained results before and after aging at 175C for 250 and 500h, are compared with static strength properties. The Laser Doppler Vibrometry measurements of the modal damping factors, show general increasing tendency for the unidirectional composites after aging, but decreasing tendency for quasi-isotropic plates. The DMA damping measurements reveal an increase of the damping in longitudinal direction after aging, but a decrease in transverse direction. Comparison of results of dynamic measurements with static properties, confirm that mechanism of damping in composite structures depends mainly on stacking sequence. Moreover, modal damping of unidirectional composites depends mainly on the properties of the fibermatrix interface, while damping of the quasi-isotropic laminates is affected by long-term properties of the matrix. Thus, to ensure long term damping performance of the carbon/epoxy components subjected to vibrations, one should take into account the stability of the matrix and fibermatrix interfaces and also the alignment of the reinforcing fibers.}
}
2Mlyniec, A. and Morawska-Chochol, A. and Kloch, K. and Uhl, T., "Phenomenological and chemomechanical modeling of the thermomechanical stability of liquid silicone rubbers", Polym. Degrad. Stab., 99 , 290--297, 2014 Link BIB
@article{Mlyniec2014a,
author = {Mlyniec, A. and Morawska-Chochol, A. and Kloch, K. and Uhl, T.},
issn = {01413910},
journal = {Polym. Degrad. Stab.},
month = jan,
pages = {290--297},
title = {{Phenomenological and chemomechanical modeling of the thermomechanical stability of liquid silicone rubbers}},
url = {http://www.sciencedirect.com/science/article/pii/S0141391013003546},
volume = {99},
year = {2014},
abstract = {In this article, we present the constitutive models taking into account the stability of liquid silicone rubber's. We propose the phenomenological large strain viscoelastic material model and the enhanced chemomechanical model. The phenomenological model is calibrated to the experimental investigations probing the thermomechanical behavior of liquid silicone rubber's, while the chemomechanical model uses kinetic theory, to calculate the changes of mechanical properties in time. The proposed chemomechanical model employs: chemical reaction kinetics, statistical mechanics and microstructural based Bergstrm-Boyce material model. Viscoelastic material property changes resulting from e.g. the variation of crosslink density are computed using the Arrhenius equation. The material model is validated by comparison with results of compression tests of specimens aged in 125 and 175 C non-loaded and under stress of 0.48 MPa. We achieve 96\% compliance for investigated temperature and pressure range. The good agreement with the experimental data, demonstrates that chemomechanical modeling framework provides a useful tool for the prediction of the stability of liquid silicone rubbers and the lifetime of vibration isolators.}
}