Pub Date : 2001-11-11DOI: 10.1115/imece2001/bed-23075
K. Parker, D. Ingber
We conducted studies using micropatterned substrates to elucidate how cell shape and geometric confinement regulates the inter- and intracellular signaling pathways required for cell motility. When cells were cultured on individual cell-sized square adhesive islands coated with ECM, they extend to the edge of the island and assume a square shape. When these cells were stimulated with growth factors, they preferentially extended lamellipodia from the corners versus the sides. This process was mediated by myosin-generated isometric tension that induced tight spatial localization of Rac in the corners. When two or three capillary endothelial cells are constrained to a fibronectin (FN) island, coordinated cell migration results in stable rotation of the entire system about its center. Thus, the emergent pattern is due to the coordinated migration behavior of the cells. These observations suggest that ECM-induced mechanotransduction potentiates compartmentalized signaling pathways and the multicellular organization required of tissue morphogenesis.
{"title":"Cell Motility in Microfabricated Models of the Tissue Microenvironment","authors":"K. Parker, D. Ingber","doi":"10.1115/imece2001/bed-23075","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23075","url":null,"abstract":"\u0000 We conducted studies using micropatterned substrates to elucidate how cell shape and geometric confinement regulates the inter- and intracellular signaling pathways required for cell motility. When cells were cultured on individual cell-sized square adhesive islands coated with ECM, they extend to the edge of the island and assume a square shape. When these cells were stimulated with growth factors, they preferentially extended lamellipodia from the corners versus the sides. This process was mediated by myosin-generated isometric tension that induced tight spatial localization of Rac in the corners. When two or three capillary endothelial cells are constrained to a fibronectin (FN) island, coordinated cell migration results in stable rotation of the entire system about its center. Thus, the emergent pattern is due to the coordinated migration behavior of the cells. These observations suggest that ECM-induced mechanotransduction potentiates compartmentalized signaling pathways and the multicellular organization required of tissue morphogenesis.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"13 7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85401214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/bed-23063
Ines M. Basalo, G. Ateshian
In recent studies of articular diarthrodial joint lubrication, it has been proposed that hydrostatic pressurization of the cartilage interstitial fluid upon joint loading contributes significantly to the load support across the articular layers, thus reducing frictional forces and wear [1–3]. This boundary contact mechanism for porous media can explain the observed time-dependent response of the frictional coefficient. Nevertheless, alternative hypotheses have been also proposed which attribute the low friction coefficient to hydrodynamic lubrication [4]. In our recent analysis of a mixed lubrication problem where a lubricant pool is trapped between a rippled rigid indenter and a biphasic cartilage layer [5], it was observed that the hydrostatic pressurization of the trapped lubricant can enhance the fluid load support to a certain extent, but typically for a short duration on the order of 1 s only, until the lubricant is depleted by flowing into the cartilage layer. Furthermore, under steady-state sliding, it was found that a lubricant pool could not be sustained due to lubricant depletion. These analyses employed an inviscid model for the lubricant as they focused on hydrostatic pressurization only. In the current study, we investigate whether lubricant viscosity, which can promote hydrodynamic pressurization, might further enhance the fluid load support mechanism or alter the conclusions gathered from our earlier studies. To investigate these fundamental mechanisms, an elastic layer is used instead of a biphasic layer at first; a more elaborate biphasic analysis could be employed subsequently if warranted by the current findings.
{"title":"Hydrodynamic Pressurization of a Trapped Lubricant Pool Between a Rippled Rigid Indenter and an Elastic Layer: An Investigation Into the Role of Surface Roughness on Cartilage Lubrication","authors":"Ines M. Basalo, G. Ateshian","doi":"10.1115/imece2001/bed-23063","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23063","url":null,"abstract":"\u0000 In recent studies of articular diarthrodial joint lubrication, it has been proposed that hydrostatic pressurization of the cartilage interstitial fluid upon joint loading contributes significantly to the load support across the articular layers, thus reducing frictional forces and wear [1–3]. This boundary contact mechanism for porous media can explain the observed time-dependent response of the frictional coefficient. Nevertheless, alternative hypotheses have been also proposed which attribute the low friction coefficient to hydrodynamic lubrication [4]. In our recent analysis of a mixed lubrication problem where a lubricant pool is trapped between a rippled rigid indenter and a biphasic cartilage layer [5], it was observed that the hydrostatic pressurization of the trapped lubricant can enhance the fluid load support to a certain extent, but typically for a short duration on the order of 1 s only, until the lubricant is depleted by flowing into the cartilage layer. Furthermore, under steady-state sliding, it was found that a lubricant pool could not be sustained due to lubricant depletion. These analyses employed an inviscid model for the lubricant as they focused on hydrostatic pressurization only. In the current study, we investigate whether lubricant viscosity, which can promote hydrodynamic pressurization, might further enhance the fluid load support mechanism or alter the conclusions gathered from our earlier studies. To investigate these fundamental mechanisms, an elastic layer is used instead of a biphasic layer at first; a more elaborate biphasic analysis could be employed subsequently if warranted by the current findings.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"62 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79497995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/bed-23150
T. M. Freyman, I. Yannas, Y. Pek, Rayka Yokoo, L. Gibson
Contractile fibroblasts play a major role in the synthesis and remodeling of scar tissue following dermal injury. Inhibition of dermal wound contraction by contractile fibroblasts, using a collagen-GAG matrix, has been linked to the blocking of scar formation[1]. Scar tissue is mechanically and functionally inferior to the dermal tissue which it replaces. Specifically, scar tissue is weaker, physically disfiguring, and can lead to restricted joint mobility.
{"title":"Micromechanics of Fibroblast Contraction of a Collagen-Gag Matrix","authors":"T. M. Freyman, I. Yannas, Y. Pek, Rayka Yokoo, L. Gibson","doi":"10.1115/imece2001/bed-23150","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23150","url":null,"abstract":"\u0000 Contractile fibroblasts play a major role in the synthesis and remodeling of scar tissue following dermal injury. Inhibition of dermal wound contraction by contractile fibroblasts, using a collagen-GAG matrix, has been linked to the blocking of scar formation[1]. Scar tissue is mechanically and functionally inferior to the dermal tissue which it replaces. Specifically, scar tissue is weaker, physically disfiguring, and can lead to restricted joint mobility.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"419 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79509357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/bed-23141
Shunichi Kobayashi, Takeshi Horie, Tomohito Amaya, H. Morikawa, D. Tang, D. Ku
Blood flow through the constricted area of a severe stenosis is similar to that through a venturi or flow nozzle. In the contraction section, the blood can accelerate to high speed. In this situation, the external pressure may be greater than the internal fluid pressure, and the artery could collapse. This collapse may be important in the development of atherosclerotic plaque fracture and subsequent thrombosis or distal embolization [1,2]. We used an asymmetric experimental model that closely approximates the arterial disease situation where the entire stenosis is compliant and the stenosis wall was not rigidly constrained. This study was to examine the relationships between flow rate, pressure and eccentricity of the stenosis inducing collapse under steady flow.
{"title":"Flow and Compression in Collapsible Asymmetric Stenosis Models of Arterial Disease","authors":"Shunichi Kobayashi, Takeshi Horie, Tomohito Amaya, H. Morikawa, D. Tang, D. Ku","doi":"10.1115/imece2001/bed-23141","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23141","url":null,"abstract":"\u0000 Blood flow through the constricted area of a severe stenosis is similar to that through a venturi or flow nozzle. In the contraction section, the blood can accelerate to high speed. In this situation, the external pressure may be greater than the internal fluid pressure, and the artery could collapse. This collapse may be important in the development of atherosclerotic plaque fracture and subsequent thrombosis or distal embolization [1,2]. We used an asymmetric experimental model that closely approximates the arterial disease situation where the entire stenosis is compliant and the stenosis wall was not rigidly constrained. This study was to examine the relationships between flow rate, pressure and eccentricity of the stenosis inducing collapse under steady flow.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85283596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/bed-23043
D. Reiter, N. Sarigul-Klijn, Munish C. Gupta, F. Fathallah
It has been observed that astronauts gain height up to 7 cm during space flight due to microgravity effects. This is due partly to the swelling of inter vertabral Dics (IVD). As a result of this most astronauts experiences low back pain. The mechanisms of pain are not well understood yet. The physiological changes that occur from microgravity environment are simulated via bed rest studies on earth. These studies verify the height change and are good simulations of the microgravity of Space Flight. There has not been any studies showing how the fluid shift effects the kinematics of the spine. In our study we designed a ground based in-vitro experiment to measure the kinematics changes induced by microgravity on spine.
{"title":"In-Vitro Measurements of Microgravity Induced Kinematics Changes on Spine","authors":"D. Reiter, N. Sarigul-Klijn, Munish C. Gupta, F. Fathallah","doi":"10.1115/imece2001/bed-23043","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23043","url":null,"abstract":"\u0000 It has been observed that astronauts gain height up to 7 cm during space flight due to microgravity effects. This is due partly to the swelling of inter vertabral Dics (IVD). As a result of this most astronauts experiences low back pain. The mechanisms of pain are not well understood yet. The physiological changes that occur from microgravity environment are simulated via bed rest studies on earth. These studies verify the height change and are good simulations of the microgravity of Space Flight. There has not been any studies showing how the fluid shift effects the kinematics of the spine. In our study we designed a ground based in-vitro experiment to measure the kinematics changes induced by microgravity on spine.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"62 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83974082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/bed-23118
M. Thubrikar, F. Robicsek, M. Labrosse, V. Chervenkoff, B. Fowler
Various factors are considered to play a role in the risk of abdominal aortic aneurysm (AAA) rupture. For instance, a maximum diameter of 7 cm is commonly used as an indication for surgery. There is a need for understanding what makes an aneurysm most likely to rupture. Our focus here is on the role of the intraluminal thrombus and how it affects the pressure and dilation experienced by the aneurysm wall. Since in most of the surgical procedures, the whole aneurysms are almost never removed, the data on the whole aneurysms with thrombus has not been available. The results presented here, therefore, are very important even though they come from a small number of whole aneurysms explored thoroughly. Two types of studies were performed: 1) in vitro and in vivo pressure measurements through the thrombus in three complete AAA, and 2) in vitro dilation measurements during pressurization of two whole aneurysms before and after the thrombus was removed.
{"title":"Effect of Thrombus in AAA on Pressure and Dilation Experienced by the Aneurysm Wall","authors":"M. Thubrikar, F. Robicsek, M. Labrosse, V. Chervenkoff, B. Fowler","doi":"10.1115/imece2001/bed-23118","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23118","url":null,"abstract":"\u0000 Various factors are considered to play a role in the risk of abdominal aortic aneurysm (AAA) rupture. For instance, a maximum diameter of 7 cm is commonly used as an indication for surgery. There is a need for understanding what makes an aneurysm most likely to rupture. Our focus here is on the role of the intraluminal thrombus and how it affects the pressure and dilation experienced by the aneurysm wall. Since in most of the surgical procedures, the whole aneurysms are almost never removed, the data on the whole aneurysms with thrombus has not been available. The results presented here, therefore, are very important even though they come from a small number of whole aneurysms explored thoroughly. Two types of studies were performed: 1) in vitro and in vivo pressure measurements through the thrombus in three complete AAA, and 2) in vitro dilation measurements during pressurization of two whole aneurysms before and after the thrombus was removed.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"65 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83134054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/bed-23053
N. Nuño, A. M. Ahmed
Numerical models of the knee joint are being increasingly used to study the internal mechanics of the joint, both in its intact condition and prosthetically resurfaced state. However, formulation of such models demands a precise knowledge of the complex three-dimensional shape of the articulating surfaces of the joint.
{"title":"Femorotibial Articulation: 3-D Morphometry and Contact Analysis","authors":"N. Nuño, A. M. Ahmed","doi":"10.1115/imece2001/bed-23053","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23053","url":null,"abstract":"\u0000 Numerical models of the knee joint are being increasingly used to study the internal mechanics of the joint, both in its intact condition and prosthetically resurfaced state. However, formulation of such models demands a precise knowledge of the complex three-dimensional shape of the articulating surfaces of the joint.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"135 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81395158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/bed-23110
D. Bluestein, J. Jesty, A. Saltman, I. Krukenkamp, Krishnamurthy Suresh
Numerical studies, in vitro, and in vivo measurements were conducted, aimed at quantifying free emboli formation and procoagulant properties of platelets induced by flow past mechanical heart valves (MHV). Pulsatile turbulent flow simulation was conducted past a St. Jude medical MHV in the aortic position, to study the effects of valve implantation technique on the thromboembolic potential of the valve. A misaligned valve with subannualarly sutured pledgets produced accelerating jet flow through the valve orifices and a wider wake of shed vortices. Shear stress histories of platelets along turbulent trajectories exposed the platelets to elevated shear stresses around the leaflets, leading them to entrapment within the shed vortices. In vitro platelet studies were conducted past the MHV mounted in a recirculation flow loop, by measuring the platelets ability to support the activation of acetylated human prothrombin by factor xa, which enables sequestering flow induced effects and quantification of the platelets activity state. The platelet activation state increased monotonically as a function of the recirculation time past the valve, as measured by the thrombin generation rates in the assay. Finally, platelet activity state measurements were conducted in vivo, from a sheep with an implanted MHV, showing marked increase of platelet activation after valve implantation.
{"title":"Platelet Activation in Flow Past Mechanical Heart Valves","authors":"D. Bluestein, J. Jesty, A. Saltman, I. Krukenkamp, Krishnamurthy Suresh","doi":"10.1115/imece2001/bed-23110","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23110","url":null,"abstract":"\u0000 Numerical studies, in vitro, and in vivo measurements were conducted, aimed at quantifying free emboli formation and procoagulant properties of platelets induced by flow past mechanical heart valves (MHV). Pulsatile turbulent flow simulation was conducted past a St. Jude medical MHV in the aortic position, to study the effects of valve implantation technique on the thromboembolic potential of the valve. A misaligned valve with subannualarly sutured pledgets produced accelerating jet flow through the valve orifices and a wider wake of shed vortices. Shear stress histories of platelets along turbulent trajectories exposed the platelets to elevated shear stresses around the leaflets, leading them to entrapment within the shed vortices. In vitro platelet studies were conducted past the MHV mounted in a recirculation flow loop, by measuring the platelets ability to support the activation of acetylated human prothrombin by factor xa, which enables sequestering flow induced effects and quantification of the platelets activity state. The platelet activation state increased monotonically as a function of the recirculation time past the valve, as measured by the thrombin generation rates in the assay. Finally, platelet activity state measurements were conducted in vivo, from a sheep with an implanted MHV, showing marked increase of platelet activation after valve implantation.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90864559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/bed-23119
M. L. Raghavan, M. Fillinger, S. P. Marra, F. Kennedy
Clinical experience with regard to predicting abdominal aortic aneurysm (AAA) rupture has shown that although AAA diameter is a good indicator, there are likely other risk factors. Some researchers have explored a biomechanical approach to predicting aneurysm rupture risk [1,2] based on the hypothesis that aneurysm rupture occurs when the mechanical stresses in the aortic wall exceed the wall failure strength. Therefore, knowledge of wall stresses in a particular AAA may help identify impending rupture. Recently, researchers have used patients’ abdominal CT scan data and blood pressure to estimate in-vivo AAA wall stresses [3]. In the present project, an improved automated methodology is used to predict AAA wall stress. The underlying correlation between mechanical stress and aneurysm wall rupture is also investigated.
{"title":"An Automated Methdology for Investigating the Correlation Between Abdominal Aortic Aneurysm Wall Stress and Risk of Rupture","authors":"M. L. Raghavan, M. Fillinger, S. P. Marra, F. Kennedy","doi":"10.1115/imece2001/bed-23119","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23119","url":null,"abstract":"\u0000 Clinical experience with regard to predicting abdominal aortic aneurysm (AAA) rupture has shown that although AAA diameter is a good indicator, there are likely other risk factors. Some researchers have explored a biomechanical approach to predicting aneurysm rupture risk [1,2] based on the hypothesis that aneurysm rupture occurs when the mechanical stresses in the aortic wall exceed the wall failure strength. Therefore, knowledge of wall stresses in a particular AAA may help identify impending rupture. Recently, researchers have used patients’ abdominal CT scan data and blood pressure to estimate in-vivo AAA wall stresses [3]. In the present project, an improved automated methodology is used to predict AAA wall stress. The underlying correlation between mechanical stress and aneurysm wall rupture is also investigated.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"72 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89947865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/bed-23086
W. Mesfar, A. Shirazi-Adl, M. Dammak
The interface friction exists in natural and artificial joints as well as many engineering systems in which different bodies articulate. It often plays an important role in mechanics of the system. In the cementless arthroplasty, the friction between the prosthesis (including stems and screws) and the host bone is exploited to increase the stability of the operation. Our previous experimental studies have shown that the interface between bone and various porous coated surfaces exhibit a nonlinear friction that remains nearly the same in different directions; a nonlinear isotropic friction [1,2]. More recent bidirectional friction tests between cancellous bone or polyurethane cubes and a metallic porous coated plate have demonstrated that the interface load-displacement curve is highly nonlinear with significant coupling between two perpendicular directions [3]. Model studies incorporating measured nonlinear response have demonstrated the importance of proper simulation of nonlinear response as compared with Coulomb friction and of the coupling between orthogonal directions [3–5]. In this study, we aim to extend the earlier model studies to incorporate nonlinear direction-dependent anisotropic friction between two surfaces. Our objectives are set to: (a) develop constitutive equations to present interfaces with nonlinear anisotropic friction properties; and (b) implement and apply in a finite element study of a cube resting on a block subjected to normal and shear loads.
{"title":"Anisotropic Nonlinear Friction at Biomaterial Interfaces: Theory and Application","authors":"W. Mesfar, A. Shirazi-Adl, M. Dammak","doi":"10.1115/imece2001/bed-23086","DOIUrl":"https://doi.org/10.1115/imece2001/bed-23086","url":null,"abstract":"\u0000 The interface friction exists in natural and artificial joints as well as many engineering systems in which different bodies articulate. It often plays an important role in mechanics of the system. In the cementless arthroplasty, the friction between the prosthesis (including stems and screws) and the host bone is exploited to increase the stability of the operation. Our previous experimental studies have shown that the interface between bone and various porous coated surfaces exhibit a nonlinear friction that remains nearly the same in different directions; a nonlinear isotropic friction [1,2]. More recent bidirectional friction tests between cancellous bone or polyurethane cubes and a metallic porous coated plate have demonstrated that the interface load-displacement curve is highly nonlinear with significant coupling between two perpendicular directions [3]. Model studies incorporating measured nonlinear response have demonstrated the importance of proper simulation of nonlinear response as compared with Coulomb friction and of the coupling between orthogonal directions [3–5]. In this study, we aim to extend the earlier model studies to incorporate nonlinear direction-dependent anisotropic friction between two surfaces. Our objectives are set to: (a) develop constitutive equations to present interfaces with nonlinear anisotropic friction properties; and (b) implement and apply in a finite element study of a cube resting on a block subjected to normal and shear loads.","PeriodicalId":7238,"journal":{"name":"Advances in Bioengineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86692538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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