TY  - CHAP
A1  - Goh, Kheng Lim
A1  - Topçu, Murat
A1  - Madabhushi, Gopal S. P.
A1  - Staat, Manfred
ED  - Maia, Fatima Raquel Azevedo
ED  - Miguel Oliveira, J.
ED  - Reis, Rui L.
T1  - Collagen fibril reinforcement in connective tissue extracellular matrices
T2  - Handbook of the extracellular matrix
N2  - The connective tissues such as tendons contain an extracellular matrix (ECM) comprising collagen fibrils scattered within the ground substance. These fibrils are instrumental in lending mechanical stability to tissues. Unfortunately, our understanding of how collagen fibrils reinforce the ECM remains limited, with no direct experimental evidence substantiating current theories. Earlier theoretical studies on collagen fibril reinforcement in the ECM have relied predominantly on the assumption of uniform cylindrical fibers, which is inadequate for modelling collagen fibrils, which possessed tapered ends. Recently, Topçu and colleagues published a paper in the International Journal of Solids and Structures, presenting a generalized shear-lag theory for the transfer of elastic stress between the matrix and fibers with tapered ends. This paper is a positive step towards comprehending the mechanics of the ECM and makes a valuable contribution to formulating a complete theory of collagen fibril reinforcement in the ECM.
KW  - Connective tissues
KW  - Extracellular matrix (ECM)
KW  - Collagen fibrils
KW  - Mechanical stability
KW  - Tapered ends
Y1  - 2023
SN  - 978-3-030-92090-6 (Print)
SN  - 978-3-030-92090-6 (Online)
U6  - http://dx.doi.org/10.1007/978-3-030-92090-6_6-1
SP  - 1
EP  - 20
PB  - Springer Nature
CY  - Cham
ER  - 
TY  - JOUR
A1  - Zhen, Manghao
A1  - Liang, Yunpei
A1  - Staat, Manfred
A1  - Li, Quanqui
A1  - Li, Jianbo
T1  - Discontinuous fracture behaviors and constitutive model of sandstone specimens containing non-parallel prefabricated fissures under uniaxial compression
JF  - Theoretical and Applied Fracture Mechanics
N2  - The deformation and damage laws of non-homogeneous irregular structural planes in rocks are the basis for studying the stability of rock engineering. To investigate the damage characteristics of rock containing non-parallel fissures, uniaxial compression tests and numerical simulations were conducted on sandstone specimens containing three non-parallel fissures inclined at 0°, 45° and 90° in this study. The characteristics of crack initiation and crack evolution of fissures with different inclinations were analyzed. A constitutive model for the discontinuous fractures of fissured sandstone was proposed. The results show that the fracture behaviors of fissured sandstone specimens are discontinuous. The stress–strain curves are non-smooth and can be divided into nonlinear crack closure stage, linear elastic stage, plastic stage and brittle failure stage, of which the plastic stage contains discontinuous stress drops. During the uniaxial compression test, the middle or ends of 0° fissures were the first to crack compared to 45° and 90° fissures. The end with small distance between 0° and 45° fissures cracked first, and the end with large distance cracked later. After the final failure, 0° fissures in all specimens were fractured, while 45° and 90° fissures were not necessarily fractured. Numerical simulation results show that the concentration of compressive stress at the tips of 0°, 45° and 90° fissures, as well as the concentration of tensile stress on both sides, decreased with the increase of the inclination angle. A constitutive model for the discontinuous fractures of fissured sandstone specimens was derived by combining the logistic model and damage mechanic theory. This model can well describe the discontinuous drops of stress and agrees well with the whole processes of the stress–strain curves of the fissured sandstone specimens.
KW  - Constitutive model
KW  - Damage mechanics theory
KW  - Discontinuous fractures
KW  - Uniaxial compression test
KW  - Non-parallel fissures
Y1  - 2024
U6  - http://dx.doi.org/10.1016/j.tafmec.2024.104373
SN  - 0167-8442
VL  - 131
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - BOOK
A1  - Staat, Manfred
A1  - Digel, Ilya
A1  - Trzewik, Jürgen
A1  - Sielemann, Stefanie
A1  - Erni, Daniel
A1  - Zylka, Waldemar
T1  - Symposium Proceedings; 4th YRA MedTech Symposium 2024 : February 1 / 2024 / FH Aachen
Y1  - 2024
SN  - 978-3-940402-65-3
U6  - http://dx.doi.org/10.17185/duepublico/81475
PB  - Universität Duisburg-Essen
CY  - Duisburg
ER  -