Article
Engineering, Biomedical
Meifeng Ren, Chi Wei Ong, Martin L. Buist, Choon Hwai Yap
Summary: The evaluation of fetal heart mechanical function is crucial for determining prognosis and making treatment decisions for congenital heart diseases. Finite Element modelling provides detailed information on fetal hearts and helps predict outcomes and support clinical decisions. This study characterized the passive mechanical properties of late fetal and neonatal porcine hearts and found no significant difference in mechanical stiffness across all age groups and between the right and left ventricular samples.
JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS
(2022)
Article
Engineering, Geological
Hua Yu, Kam Ng
Summary: The relationship between rock failure strengths under triaxial compression and extension is important for theoretical and practical purposes. Traditional criteria cannot distinguish between these two conditions, so an analytical model based on Mohr failure theory is proposed. The model can express rock failure criteria in power-law forms and is validated using experimental data.
INTERNATIONAL JOURNAL OF GEOMECHANICS
(2022)
Article
Engineering, Biomedical
David Nordsletten, Adela Capilnasiu, Will Zhang, Anna Wittgenstein, Myrianthi Hadjicharalambous, Gerhard Sommer, Ralph Sinkus, Gerhard A. Holzapfel
Summary: Understanding the biomechanics of the heart is crucial for diagnosing and treating heart failure. A new viscoelastic constitutive model for cardiac muscle has been developed, showing improved accuracy compared to traditional hyperelastic models. The model demonstrates high sensitivity, fidelity, and parameter uniqueness, and is versatile in simulating various loading phenomena.
ACTA BIOMATERIALIA
(2021)
Article
Engineering, Civil
Yu Qian, Erol Tutumluer, Youssef M. A. Hashash, Jamshid Ghaboussi
Summary: This paper investigates the behavior of new and degraded ballast samples under triaxial testing, revealing that degraded ballast samples in dry conditions did not experience significant strength loss, but exhibited higher strengths and permanent deformations under repeated load cycles. When moisture was introduced, degraded ballast showed significantly larger permanent deformations and strength losses.
TRANSPORTATION GEOTECHNICS
(2022)
Article
Engineering, Geological
Kai Liu, Wen-Bo Chen, Jian-Hua Yin, Wei-Qiang Feng, Lalit Borana
Summary: Limited studies have been conducted on the development of testing apparatus for unsaturated soils due to their complex structure and demanding calibration process. A novel multifunctional apparatus (MFA) has been designed in this study, which is capable of conducting various tests under suction-controlled conditions. The MFA has shown reliable performance in accurately investigating the engineering behavior of both saturated and unsaturated geomaterials.
Article
Biotechnology & Applied Microbiology
Bismi Rasheed, Venkat Ayyalasomayajula, Ute Schaarschmidt, Terje Vagstad, Hans Georg Schaathun
Summary: In this study, the authors used second harmonic generation (SHG) and planar biaxial tension testing to investigate the collagen fiber morphology in human meniscal tissue. They proposed a structure-based constitutive model for the tissue and found that the bottom samples had circumferentially organized fibers. Biaxial testing showed an anisotropic response, with the circumferential direction being stiffer. A hyperelastic material model based on the generalized structure tensor approach was developed and showed good agreement with the experimental data.
FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Dongsong Song, Hongshuai Liu, Qiangqiang Sun
Summary: Previous research has lacked a quantitative study on the effects of determination methods on the shear modulus G and modulus reduction curve G/G(max), and this study aims to evaluate the uncertainties associated with the shear modulus measurements introduced by four determination methods. The results show that the calculated G/G(max) may differ significantly for the same hysteresis loop, highlighting the need for careful consideration of the asymmetrical hysteresis loop at large strains.
APPLIED SCIENCES-BASEL
(2022)
Article
Multidisciplinary Sciences
Harry Ngwangwa, Thanyani Pandelani, Makhosasana Msibi, Israel Mabuda, Letlhogonolo Semakane, Fulufhelo Nemavhola
Summary: This study investigated the biomechanical properties of the esophagus under biaxial mechanical tensile testing, fitting experimental data to six hyperelastic constitutive models and finding that the Four-Fiber model had the best fit.
Article
Polymer Science
Wenqian Zhai, Damien Soulat, Xavier Legrand, Peng Wang
Summary: In this study, the non-symmetric in-plane shear behavior of flax/polypropylene 2D biaxial braided preform for thermoplastic biocomposites was characterized using bias-extension test. The effects of temperature, unit cell geometry parameters, and overall fiber volume fraction on the shear behavior were investigated. A simulation of thermal impregnation distribution based on unit cell geometry was also performed.
Article
Mechanics
Renye Cai, Frederic Holweck, Zhi-Qiang Feng, Francois Peyraut
Summary: This paper proposes a new Strain Energy Function (SEF) for modeling incompressible orthotropic hyperelastic materials with a specific application to the mechanical response of passive ventricular myocardium. By selecting a set of polyconvex invariants, the model can predict the experimental data with 6 different shear modes applied to passive ventricular myocardium.
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
(2021)
Article
Engineering, Geological
Pauline Kaminski, Jurgen Grabe
Summary: Small amounts of gas can be found in almost every sediment in marine or coastal environments. Previous studies have shown that gas can negatively affect the mechanical properties of soil, particularly in tide affected areas where geohazard occurrence and dike safety are a concern. However, the impact of a homogeneous distribution of gas bubbles in soil on its mechanical properties remains poorly understood. In order to further investigate the shear strength of gassy soils, an experimental setup and sample preparation procedure using the axis-translation method were developed.
GEOTECHNICAL TESTING JOURNAL
(2023)
Article
Engineering, Geological
Cyrille Couture, Pierre Besuelle
Summary: This paper presents a general three-invariant model to evaluate the theoretical prediction of strain localization against laboratory measurements. The model is calibrated using extensive experimental data and a mean stress and Lode angle-dependent yield surface. The model is further validated by comparing with other simplified models using the same dataset.
Article
Chemistry, Physical
Weifeng Jin, Ying Tao, Xin Wang, Zheng Gao
Summary: By reinforcing sand with carbon nanotubes dispersed in colloidal silica, the shear strength of sandy ground can be significantly improved. Experimental results showed that the shear strength is affected by different concentrations of colloidal silica and carbon nanotubes, with certain thresholds and peak values observed. SEM images demonstrated that the interconnected carbon nanotubes in micro-cracks of the silica gel contribute to the macroscopic shear strength.
Article
Green & Sustainable Science & Technology
Junhua Chen, Yanjiang Zhang, Yanxin Yang, Bai Yang, Bocheng Huang, Xinping Ji
Summary: This paper investigates the influence of variation in the content of coarse grains on the mechanical properties of coarse-grained red sandstone soil. Triaxial shear tests were conducted on soil specimens with different content of coarse grains. The results showed that the deviation stress of static failure and internal friction angle increased hyperbolically with the increase of coarse grain content, while cohesion reached a peak value and then decreased. The optimum value for coarse-grained red sandstone soil as a filling material was found to be a coarse grain content of 30%.
Article
Engineering, Mechanical
Alexandros Stathas, Ioannis Stefanou
Summary: Earthquake faults result from severe strain localization in rocks, which is controlled by the size of the microstructure and various Thermo-Hydro-Mechanical (THM) couplings. Our modeling using the Cosserat theory and considering large shear deformations during seismic slip justifies the rate and state friction law. We find the presence of traveling shear bands along the thickness of the fault, leading to oscillations in the fault's frictional response.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Engineering, Biomedical
Emmanouil Agrafiotis, Christian Mayer, Martin Grabenwoeger, Daniel Zimpfer, Peter Regitnig, Heinrich Maechler, Gerhard A. Holzapfel
Summary: This study examined the effects of thoracic endovascular repair (TEVAR) on the biomechanical properties of the aorta. It found that TEVAR resulted in reduced aortic distensibility, stiffness mismatch, and histological remodeling of the aortic wall. These findings have implications for improving stent-graft design and minimizing complications.
ACTA BIOMATERIALIA
(2023)
Article
Engineering, Biomedical
Anna Pukaluk, Heimo Wolinski, Christian Viertler, Peter Regitnig, Gerhard A. Holzapfel, Gerhard Sommer
Summary: This study focuses on the changes in collagen and elastin microstructure in the aortic adventitia under macroscopic equibiaxial loading. The results show that collagen fibers in the adventitia divide into two families under loading, while elastin fibers do not show clear orientation. These findings provide important insights into the stretching process of the aortic wall.
ACTA BIOMATERIALIA
(2023)
Article
Engineering, Biomedical
Francesco Giovanniello, Meisam Asgari, Ivan D. Breslavsky, Giulio Franchini, Gerhard A. Holzapfel, Maryam Tabrizian, Marco Amabili
Summary: In this study, scaffolds with ideal static and dynamic mechanical properties, similar to natural human aortas, were successfully obtained through an optimized decellularization protocol. This provides an ideal choice for developing innovative aortic grafts.
ACTA BIOMATERIALIA
(2023)
Article
Chemistry, Multidisciplinary
Miriam de J. Velasquez-Hernandez, Mercedes Linares-Moreau, Lea A. A. Brandner, Benedetta Marmiroli, Mariano Barella, Guillermo P. P. Acuna, Simone Dal Zilio, Margot F. K. Verstreken, Dmitry E. E. Kravchenko, Oliver M. M. Linder-Patton, Jack D. D. Evans, Helmar Wiltsche, Francesco Carraro, Heimo Wolinski, Rob Ameloot, Christian Doonan, Paolo Falcaro
Summary: A patternable oriented MOF film is designed by using X-ray exposure to decompose the MOF film in the irradiated areas and remain intact in the unexposed regions. This MOF patterning protocol can be used for the microfabrication of optical components for photonic devices.
ADVANCED MATERIALS
(2023)
Article
Engineering, Multidisciplinary
Kevin Linka, Adrian Buganza Tepole, Gerhard A. Holzapfel, Ellen Kuhl
Summary: Choosing the best constitutive model and parameters in continuum mechanics has traditionally relied on user experience and preference. This paper proposes a new method that autonomously discovers the best model and parameters to explain experimental data using a neural network. The method is robust and satisfies physical constraints, and has the potential to revolutionize the field of constitutive modeling. Evaluation: 8 points
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Will Zhang, Javiera Jilberto, Gerhard Sommer, Michael S. Sacks, Gerhard A. Holzapfel, David A. Nordsletten
Summary: Biomechanics is important in diagnosing and treating heart conditions. Computational models can provide personalized treatment options but require accurate constitutive equations for biomechanical behavior prediction. A fractional viscoelastic modeling approach that accurately captures the viscoelastic response of the human myocardium was previously developed. This approach has comparable computational costs and only requires two additional material parameters. In this study, the implementation of this approach in Finite Element Analysis was presented, numerical properties were examined, and the physiological implications were explored.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Toxicology
Franziska Poeschl, Theresa Hoeher, Sarah Pirklbauer, Heimo Wolinski, Lisa Lienhart, Miriam Ressler, Monika Riederer
Summary: This study demonstrates the effects of DON in a gut-on-a-chip model, which incorporates the effects of intestinal flow. DON causes dysfunction of intestinal barrier, with lower concentrations inducing TEER increase and higher concentrations leading to barrier disruption and IL-8 secretion.
TOXICOLOGY IN VITRO
(2023)
Article
Endocrinology & Metabolism
Gabriel Chalhoub, Alina Jamnik, Laura Pajed, Stephanie Kolleritsch, Victoria Hois, Antonia Bagaric, Dominik Prem, Anna Tilp, Dagmar Kolb, Heimo Wolinski, Ulrike Taschler, Thomas Zuellig, Gerald N. Rechberger, Claudia Fuchs, Michael Trauner, Gabriele Schoiswohl, Guenter Haemmerle
Summary: The abnormal generation of lipid metabolites and signaling molecules, including DAG and lysoPC, play a critical role in the development and progression of NAFLD. Ces2a and CES2 are key players in lipid metabolism, regulating the hydrolysis of DAG and lysoPC.
MOLECULAR METABOLISM
(2023)
Article
Microbiology
Himadri B. B. Thapa, Paul Kohl, Franz G. G. Zingl, Dominik Fleischhacker, Heimo Wolinski, Thomas A. A. Kufer, Stefan Schild
Summary: The release of membrane vesicles from bacteria plays an important role in intra- and interspecies communication. Although the immunomodulatory properties of bacterial membrane vesicles (MVs) have been recognized, their interactions with host cells and underlying signaling pathways are not well understood. This study provides a comparative analysis of the proinflammatory cytokine response of human intestinal epithelial cells to MVs derived from different gut bacteria. The results show that outer membrane vesicles (OMVs) from Gram-negative bacteria induce a stronger proinflammatory response than MVs from Gram-positive bacteria, and the immunomodulatory activities vary between different species.
MICROBIOLOGY SPECTRUM
(2023)
Article
Engineering, Biomedical
Will Zhang, Majid Jadidi, Sayed Ahmadreza Razian, Gerhard A. Holzapfel, Alexey Kamenskiy, David A. Nordsletten
Summary: This study introduces a new viscoelastic constitutive model for the human femoropopliteal artery, which accurately describes its mechanical characteristics and time-dependent behavior. The model improves the accuracy of computational simulations and expands our knowledge of arterial mechanophysiology.
ACTA BIOMATERIALIA
(2023)
Article
Engineering, Biomedical
Federica Cosentino, Selda Sherifova, Gerhard Sommer, Giuseppe Raffa, Michele Pilato, Salvatore Pasta, Gerhard A. Holzapfel
Summary: This study investigates regional differences in ascending thoracic aortic aneurysms (ATAAs) in humans, highlighting the impact of fiber dispersion on microstructural properties and providing important biomechanical data for improving current risk stratification strategies.
ACTA BIOMATERIALIA
(2023)
Article
Engineering, Biomedical
Mohammad Javad Sadeghinia, Hans Martin Aguilera, Stig Urheim, Robert Matongo Persson, Vegard Skalstad Ellensen, Rune Haaverstad, Gerhard A. Holzapfel, Bjorn Skallerud, Victorien Prot
Summary: This study examines the mechanical behavior of Barlow and FED tissue by using biaxial mechanical tests and second harmonic generation microscopy. The results show that the Barlow sample and the most affected FED sample have different mechanical behavior and collagen structure compared to the other FED samples. The finite element model constructed based on this study shows good agreement with echocardiography and provides essential data for understanding the relationship between collagen microstructure and degenerative mitral valve mechanics.
ACTA BIOMATERIALIA
(2023)
Article
Mechanics
Daniel Ch. Haspinger, Gerhard A. Holzapfel
Summary: This study systematically analyzes the descriptive and predictive capabilities of the GST and AI approaches for modeling arterial mechanical behavior. Results show that there is no statistically significant difference in the descriptive features and minor deviations in the predictive aspects of the two modeling approaches.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2023)
Article
Multidisciplinary Sciences
Misael Dalbosco, Michele Terzano, Thiago A. Carniel, Eduardo A. Fancello, Gerhard A. Holzapfel
Summary: This study presents a multi-scale computational analysis of abdominal aortic aneurysms (AAAs), which suggests that the formation of aneurysms disrupts the micro-mechanics of healthy tissue and triggers collagen growth and remodeling through mechanosensing cells. This leads to changes in the macro-mechanics and microstructure of the tissue at a cellular scale.
JOURNAL OF THE ROYAL SOCIETY INTERFACE
(2023)
Article
Multidisciplinary Sciences
Michele Terzano, Maximilian P. Wollner, Manuel P. Kainz, Malte Rolf-Pissarczyk, Nils Gotzen, Gerhard A. Holzapfel
Summary: In situ tissue engineering provides a innovative solution for replacing valves and grafts in cardiovascular medicine. The mechanical behavior of the polymeric scaffold and its short-term response are studied using simulations and experiments.
JOURNAL OF THE ROYAL SOCIETY INTERFACE
(2023)
