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Roger C Haut - One of the best experts on this subject based on the ideXlab platform.
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Exposure to a standard culture medium alters the response of cartilage explants to injurious unconfined compression.
Journal of biomechanics, 2005Co-Authors: S. A. Rundell, Roger C HautAbstract:Previous studies on chondral explants have not clearly described to what extent the degree and the distribution of cell death are dependent on the amount of free swelling seen during tissue equilibration in a standard culture medium. The current study hypothesized that increased fluid content inside equilibrated chondral explants, when subjected to injurious compression, would lead to greater Matrix Damage during unconfined compression. Equilibrated and non-equilibrated chondral explants were loaded to 30 MPa at a fast rate of loading ( approximately 600 MPa/s). Stress-strain curves were documented for each explant. Matrix Damage was assessed by the length of surface fissures. Chondrocyte viability was also measured in the various layers of the explants. The stiffness of the equilibrated specimens was less than non-equilibrated specimens, and it correlated with the amount of fluid absorbed during equilibration. More Matrix Damage and associated cell death in the superficial zone were documented in equilibrated than non-equilibrated explants, and these correlated positively with fluid absorbed during equilibration. This study indicated that equilibration of chondral explants in a standard culture medium alters their response to mechanical loading in terms of stiffness, Matrix Damage and cell viability.
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the extent and distribution of cell death and Matrix Damage in impacted chondral explants varies with the presence of underlying bone
Journal of Biomechanical Engineering-transactions of The Asme, 2003Co-Authors: J A Krueger, Benjamin J Ewers, D Dvoracekdriksna, M W Orth, P Thisse, Roger C HautAbstract:Excessive mechanical loading can lead to Matrix Damage and chondrocyte death in articular cartilage. Previous studies on chondral and osteochondral explants have not clearly distinguished to what extent the degree and the distribution of cell death are dependent on the presence of an underlying layer of bone. The current study hypothesized that the presence of underlying bone would decrease the amount of Matrix Damage and cell death. Chondral and osteochondral explants were loaded to 30 MPa at a high rate of loading (approximately 600 MPa/s) or at a low rate of loading (30 MPa/s). After 24 hours in culture, Matrix Damage was assessed by the total length and average depth of surface fissures. The explants were also sectioned and stained for cell viability in the various layers of the cartilage. More Matrix Damage was documented in chondral than osteochondral explants for each rate of loading experiment. The total amount of cell death was also less in osteochondral explants than chondral explants. The presence of underlying bone significantly reduced the extent of cell death in all zones in low rate of loading tests. The percentage of cell death was also reduced in the intermediate zone and deep zones of the explant by the presence of the underlying bone for a high rate of loading. This study indicated that the presence of underlying bone significantly limited the degree of Matrix Damage and cell death, and also affected the distribution of dead cells through the explant thickness. These data may have relevance to the applicability of experimental data from chondral explants to the in situ condition.
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the extent of Matrix Damage and chondrocyte death in mechanically traumatized articular cartilage explants depends on rate of loading
Journal of Orthopaedic Research, 2001Co-Authors: Benjamin J Ewers, D Dvoracekdriksna, M W Orth, Roger C HautAbstract:Abstract Mechanical loads can lead to Matrix Damage and chondrocyte death in articular cartilage. This Damage has been implicated in the pathogenesis of secondary osteoarthritis. Studies on cartilage explants with the attachment of underlying bone at high rates of loading have documented cell death adjacent to surface lesions. On the other hand, studies involving explants removed from bone at low rates of loading suggest no clear spatial association between cell death and Matrix Damage. The current study hypothesized that the observed differences in the distribution of cell death in these studies are attributed to the rate of loading. Ninety bovine cartilage explants were cultured for two days. Sixty explants were loaded in unconfined compression to 40 MPa in either a fast rate of loading experiment (∼900 MPa/s) or a low rate of loading experiment (40 MPa/s). The remaining 30 explants served as a control population. All explants were cultured for four days after loading. Matrix Damage was assessed by measuring the total length and average depth of surface lesions and the release of glycosaminoglycans to the culture media. Explants were sectioned and stained with calcein and ethidium bromide homodimer to document the number of live and dead cells. Greater Matrix Damage was documented in explants subjected to a high rate of loading, compared to explants exposed to a low rate of loading. The high rate of loading experiments resulted in cell death adjacent to fissures, whereas more dead cells were observed in the low rate of loading experiments and a more diffuse distribution of dead cells was observed away from the fissures. In conclusion, this study indicated that the rate of loading can significantly affect the degree of Matrix Damage, the distribution of dead cells, and the amount of cell death in unconfined compression experiments on explants of articular cartilage.
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the extent of Matrix Damage and chondrocyte death in mechanically traumatized articular cartilage explants depends on rate of loading
Journal of Orthopaedic Research, 2001Co-Authors: Benjamin J Ewers, D Dvoracekdriksna, M W Orth, Roger C HautAbstract:Mechanical loads can lead to Matrix Damage and chondrocyte death in articular cartilage. This Damage has been implicated in the pathogenesis of secondary osteoarthritis. Studies on cartilage explants with the attachment of underlying bone at high rates of loading have documented cell death adjacent to surface lesions. On the other hand, studies involving explants removed from bone at low rates of loading suggest no clear spatial association between cell death and Matrix Damage. The current study hypothesized that the observed differences in the distribution of cell death in these studies are attributed to the rate of loading. Ninety bovine cartilage explants were cultured for two days. Sixty explants were loaded in unconfined compression to 40 MPa in either a fast rate of loading experiment (approximately 900 MPa/s) or a low rate of loading experiment (40 MPa/s). The remaining 30 explants served as a control population. All explants were cultured for four days after loading. Matrix Damage was assessed by measuring the total length and average depth of surface lesions and the release of glycosaminoglycans to the culture media. Explants were sectioned and stained with calcein and ethidium bromide homodimer to document the number of live and dead cells. Greater Matrix Damage was documented in explants subjected to a high rate of loading, compared to explants exposed to a low rate of loading. The high rate of loading experiments resulted in cell death adjacent to fissures, whereas more dead cells were observed in the low rate of loading experiments and a more diffuse distribution of dead cells was observed away from the fissures. In conclusion, this study indicated that the rate of loading can significantly affect the degree of Matrix Damage, the distribution of dead cells, and the amount of cell death in unconfined compression experiments on explants of articular cartilage.
Hong Wu Song - One of the best experts on this subject based on the ideXlab platform.
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microstructure based numerical simulation of the tensile behavior of sicp al composites
Journal of Materials Engineering and Performance, 2014Co-Authors: Ying Kan, Z G Liu, Shenghu Zhang, Lingxuan Zhang, M Cheng, Hong Wu SongAbstract:Modeling and prediction of the Damage evolution in particle reinforced composites is a complex problem. Microstructure characters such as the particle morphologies, sizes, and distribution significantly affect the Damage evolution in composites. A numerical simulation has been performed to investigate the Damage evolution of SiCp/AA2009 composites. Tensile deformation in SiCp/AA2009 composites was simulated using the microstructure-based model constructed from the metallograph. Matrix Damage, particle cracking, and interface debonding were simulated combining the ductile Damage model, the normal stress criterion, and the maximum stress ratio criterion. The simulation results show that under tensile loading, Damage initiates at the interface, and then propagates along the weakest direction. The simulation microstructures agree well with experimental results in which interface debonding, particle cracking, and Matrix Damage co-exist. In addition, the effects of component properties on the Damage evolution are examined for various situations.
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Microstructure-Based Numerical Simulation of the Tensile Behavior of SiCp/Al Composites
Journal of Materials Engineering and Performance, 2013Co-Authors: Kan Ying, Z G Liu, Shenghu Zhang, Lingxuan Zhang, M Cheng, Hong Wu SongAbstract:Modeling and prediction of the Damage evolution in particle reinforced composites is a complex problem. Microstructure characters such as the particle morphologies, sizes, and distribution significantly affect the Damage evolution in composites. A numerical simulation has been performed to investigate the Damage evolution of SiCp/AA2009 composites. Tensile deformation in SiCp/AA2009 composites was simulated using the microstructure-based model constructed from the metallograph. Matrix Damage, particle cracking, and interface debonding were simulated combining the ductile Damage model, the normal stress criterion, and the maximum stress ratio criterion. The simulation results show that under tensile loading, Damage initiates at the interface, and then propagates along the weakest direction. The simulation microstructures agree well with experimental results in which interface debonding, particle cracking, and Matrix Damage co-exist. In addition, the effects of component properties on the Damage evolution are examined for various situations.
Benjamin J Ewers - One of the best experts on this subject based on the ideXlab platform.
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the extent and distribution of cell death and Matrix Damage in impacted chondral explants varies with the presence of underlying bone
Journal of Biomechanical Engineering-transactions of The Asme, 2003Co-Authors: J A Krueger, Benjamin J Ewers, D Dvoracekdriksna, M W Orth, P Thisse, Roger C HautAbstract:Excessive mechanical loading can lead to Matrix Damage and chondrocyte death in articular cartilage. Previous studies on chondral and osteochondral explants have not clearly distinguished to what extent the degree and the distribution of cell death are dependent on the presence of an underlying layer of bone. The current study hypothesized that the presence of underlying bone would decrease the amount of Matrix Damage and cell death. Chondral and osteochondral explants were loaded to 30 MPa at a high rate of loading (approximately 600 MPa/s) or at a low rate of loading (30 MPa/s). After 24 hours in culture, Matrix Damage was assessed by the total length and average depth of surface fissures. The explants were also sectioned and stained for cell viability in the various layers of the cartilage. More Matrix Damage was documented in chondral than osteochondral explants for each rate of loading experiment. The total amount of cell death was also less in osteochondral explants than chondral explants. The presence of underlying bone significantly reduced the extent of cell death in all zones in low rate of loading tests. The percentage of cell death was also reduced in the intermediate zone and deep zones of the explant by the presence of the underlying bone for a high rate of loading. This study indicated that the presence of underlying bone significantly limited the degree of Matrix Damage and cell death, and also affected the distribution of dead cells through the explant thickness. These data may have relevance to the applicability of experimental data from chondral explants to the in situ condition.
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the extent of Matrix Damage and chondrocyte death in mechanically traumatized articular cartilage explants depends on rate of loading
Journal of Orthopaedic Research, 2001Co-Authors: Benjamin J Ewers, D Dvoracekdriksna, M W Orth, Roger C HautAbstract:Abstract Mechanical loads can lead to Matrix Damage and chondrocyte death in articular cartilage. This Damage has been implicated in the pathogenesis of secondary osteoarthritis. Studies on cartilage explants with the attachment of underlying bone at high rates of loading have documented cell death adjacent to surface lesions. On the other hand, studies involving explants removed from bone at low rates of loading suggest no clear spatial association between cell death and Matrix Damage. The current study hypothesized that the observed differences in the distribution of cell death in these studies are attributed to the rate of loading. Ninety bovine cartilage explants were cultured for two days. Sixty explants were loaded in unconfined compression to 40 MPa in either a fast rate of loading experiment (∼900 MPa/s) or a low rate of loading experiment (40 MPa/s). The remaining 30 explants served as a control population. All explants were cultured for four days after loading. Matrix Damage was assessed by measuring the total length and average depth of surface lesions and the release of glycosaminoglycans to the culture media. Explants were sectioned and stained with calcein and ethidium bromide homodimer to document the number of live and dead cells. Greater Matrix Damage was documented in explants subjected to a high rate of loading, compared to explants exposed to a low rate of loading. The high rate of loading experiments resulted in cell death adjacent to fissures, whereas more dead cells were observed in the low rate of loading experiments and a more diffuse distribution of dead cells was observed away from the fissures. In conclusion, this study indicated that the rate of loading can significantly affect the degree of Matrix Damage, the distribution of dead cells, and the amount of cell death in unconfined compression experiments on explants of articular cartilage.
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the extent of Matrix Damage and chondrocyte death in mechanically traumatized articular cartilage explants depends on rate of loading
Journal of Orthopaedic Research, 2001Co-Authors: Benjamin J Ewers, D Dvoracekdriksna, M W Orth, Roger C HautAbstract:Mechanical loads can lead to Matrix Damage and chondrocyte death in articular cartilage. This Damage has been implicated in the pathogenesis of secondary osteoarthritis. Studies on cartilage explants with the attachment of underlying bone at high rates of loading have documented cell death adjacent to surface lesions. On the other hand, studies involving explants removed from bone at low rates of loading suggest no clear spatial association between cell death and Matrix Damage. The current study hypothesized that the observed differences in the distribution of cell death in these studies are attributed to the rate of loading. Ninety bovine cartilage explants were cultured for two days. Sixty explants were loaded in unconfined compression to 40 MPa in either a fast rate of loading experiment (approximately 900 MPa/s) or a low rate of loading experiment (40 MPa/s). The remaining 30 explants served as a control population. All explants were cultured for four days after loading. Matrix Damage was assessed by measuring the total length and average depth of surface lesions and the release of glycosaminoglycans to the culture media. Explants were sectioned and stained with calcein and ethidium bromide homodimer to document the number of live and dead cells. Greater Matrix Damage was documented in explants subjected to a high rate of loading, compared to explants exposed to a low rate of loading. The high rate of loading experiments resulted in cell death adjacent to fissures, whereas more dead cells were observed in the low rate of loading experiments and a more diffuse distribution of dead cells was observed away from the fissures. In conclusion, this study indicated that the rate of loading can significantly affect the degree of Matrix Damage, the distribution of dead cells, and the amount of cell death in unconfined compression experiments on explants of articular cartilage.
Daining Fang - One of the best experts on this subject based on the ideXlab platform.
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A new constitutive model of micro-particle reinforced metal Matrix composites with Damage effects
International Journal of Mechanical Sciences, 2019Co-Authors: Shaohua Chen, Daining FangAbstract:Abstract It is well known that the mechanical behavior of micro-particle-reinforced metal Matrix composites (MPMMCs) in service is significantly influenced by the particle size, Matrix Damage and interface debonding. In order to characterize the mechanical property of such a two-phased elasto-plastic material with the three kinds of effects, a new theoretical model is developed based on the secant modulus method, a low-order strain gradient theory with Damage and an effective reduced moduli approach, in which both the size effect of reinforcing particles and the effects of Matrix Damage and interface debonding are included. As a result, a non-linear elasto-plastic constitutive relation is achieved, with which the stress-strain response of MPMMCs in both uniaxial tension and uniaxial compression tests can be reproduced very well, in contrast to the predictions by the existing strain gradient theories without considering Damage. An interesting phenomenon is further found that the dominant role of Damage in MPMMCs changes from the interface debonding to the Matrix Damage with the increase of load in tension test, while the Matrix Damage always dominates in compression test. The present study provides not only a more comprehensive understanding of the in-service performance of MPMMCs but also a useful theoretical tool for mechanical prediction and optimizing design of other advanced composite materials.
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Damage of short-fiber-reinforced metal Matrix composites considering cooling and thermal cycling
Journal of Engineering Materials and Technology-transactions of The Asme, 1999Co-Authors: Chuwei Zhou, Wei Yang, Daining FangAbstract:Mechanical properties and Damage evolution of short-fiber-reinforced metal Matrix composites (MMC) are studied under a micromechanics model accounting for the history of cooling and thermal cycling. A cohesive interface is formulated in conjunction with the Gurson-Tvergaard Matrix Damage model. Attention is focused on the residual stresses and Damages by the thermal mismatch. Substantial stress drop in the uniaxial tensile response is found for a computational cell that experienced a cooling process. The stress drop is caused by debonding along the fiber ends. Subsequent thermal cycling lowers the debonding stress and the debonding strain. Micromechanics analysis reveals three failure modes. When the thermal histories are ignored, the cell fails by Matrix Damage outside the fiber ends. With the incorporation of cooing, the cell fails by fiber end debonding and the subsequent transverse Matrix Damage. When thermal cycling is also included, the cell fails by jagged debonding around the fiber tops followed by necking instability of Matrix ligaments.
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A numerical strength analysis of metal Matrix composites considering the interface and Matrix Damage evolution
Metals and Materials, 1998Co-Authors: Chuwei Zhou, W. Yang, Daining FangAbstract:A numerical micromechanical method is adopted here to investigate the tensile strength of metal Matrix composites (MMC) by considering interface and Matrix Damage evolution. A cohesive zone model is employed to simulate the fiber/Matrix interface Damage. The Damage in the Matrix, which characterizes microvoid nucleation, growth and coalescence, is described in term of the Gurson-Tvergaard material model. These Damage models are performed to a boundary value problem that involves a double periodic array of elastic continuous fibers in the elastic-plastic Matrix subjected to transverse loads. The main attempt is made to investigate effects of interface strength and toughness on tensile strength of MMC.
Ying Kan - One of the best experts on this subject based on the ideXlab platform.
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microstructure based numerical simulation of the tensile behavior of sicp al composites
Journal of Materials Engineering and Performance, 2014Co-Authors: Ying Kan, Z G Liu, Shenghu Zhang, Lingxuan Zhang, M Cheng, Hong Wu SongAbstract:Modeling and prediction of the Damage evolution in particle reinforced composites is a complex problem. Microstructure characters such as the particle morphologies, sizes, and distribution significantly affect the Damage evolution in composites. A numerical simulation has been performed to investigate the Damage evolution of SiCp/AA2009 composites. Tensile deformation in SiCp/AA2009 composites was simulated using the microstructure-based model constructed from the metallograph. Matrix Damage, particle cracking, and interface debonding were simulated combining the ductile Damage model, the normal stress criterion, and the maximum stress ratio criterion. The simulation results show that under tensile loading, Damage initiates at the interface, and then propagates along the weakest direction. The simulation microstructures agree well with experimental results in which interface debonding, particle cracking, and Matrix Damage co-exist. In addition, the effects of component properties on the Damage evolution are examined for various situations.