The Experts below are selected from a list of 10797 Experts worldwide ranked by ideXlab platform
Eugene H. Blackstone - One of the best experts on this subject based on the ideXlab platform.
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Surgical management of secondary tricuspid valve regurgitation: annulus, commissure, or leaflet procedure?
The Journal of Thoracic and Cardiovascular Surgery, 2010Co-Authors: Jose L. Navia, Edward R. Nowicki, Eugene H. Blackstone, Nicolas Brozzi, Daniel E. Nento, Fernando A. Atik, Jeevanantham Rajeswaran, A. Marc Gillinov, Lars G. Svensson, Bruce W. LytleAbstract:Objectives Techniques employed today concomitantly with left-sided heart valve surgery address secondary tricuspid valve regurgitation at 3 anatomic levels—annulus, commissure, and leaflet—although success of these alone or in combination in eliminating tricuspid regurgitation is uncertain. Our objective was to assess the comparative effectiveness of these techniques in reducing or eliminating secondary tricuspid regurgitation. Methods From 1990 to 2008, 2277 patients underwent tricuspid valve procedures for secondary tricuspid regurgitation concomitantly with mitral (n = 1527, 67%), aortic (n = 180, 7.9%), or combined (n = 570, 25%) valve surgery. These included annulus (flexible prosthesis [n = 1052, 46%], Rigid prosthesis [standard = 387, 3-dimensional = 197; 26%], Peri-Guard annuloplasty [Synovis Surgical Innovations, St Paul, Minn; n = 185, 8.1%], and De Vega suture [n = 129, 5.7%]), commissure (Kay [n = 248, 11%]), and leaflet (edge-to-edge suture [n = 79, 3.5%] ± annulus or commissural) procedures. A total of 4745 postoperative transthoracic echocardiograms in 1965 patients were analyzed. Results By 3 months after surgery, only 32% of patients overall had no tricuspid regurgitation. However, by 5 years, this had decreased to 22%, and 3+/4+ tricuspid regurgitation had increased from 11% at 3 months to 17%. Patients with Rigid Ring annuloplasty alone, either standard or 3-dimensional, had the least increase of 3+/4+ tricuspid regurgitation (to 12% at 5 years) compared with either a commissural or leaflet procedure. Conclusion Rigid prosthetic Ring annuloplasty, standard or 3-dimensional, provides early and sustained reduction of tricuspid regurgitation secondary to left-sided valve disease without need for an additional leaflet procedure. However, results are imperfect, possibly because other anatomic levels (subvalvular, papillary muscle, and right ventricular) contributing to its pathophysiology are unaddressed.
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tricuspid valve repair durability and risk factors for failure
The Journal of Thoracic and Cardiovascular Surgery, 2004Co-Authors: Patrick M Mccarthy, Jeevanantham Rajeswaran, Bruce W. Lytle, Sunil K Bhudia, Katherine J Hoercher, Delos M Cosgrove, Eugene H. BlackstoneAbstract:Abstract Objectives To compare durability of tricuspid valve annuloplasty techniques, identify risk factors for repair failure, and characterize survival, reoperation, and functional class of surviving patients. Methods From 1990 to 1999, 790 patients (mean age 65 ± 12 years, 51% New York Heart Association functional class III or IV, and mean right ventricular systolic pressure 56 ± 18 mm Hg) underwent tricuspid valve annuloplasty for functional regurgitation using 4 techniques: Carpentier-Edwards semi-Rigid Ring, Cosgrove-Edwards flexible band, De Vega procedure, and customized semicircular Peri-Guard annuloplasty. Of these patients, 89% had concomitant mitral valve surgery. A total of 2245 follow-up transthoracic echocardiograms were retrieved. Tricuspid regurgitation was analyzed, and risk factors for worsening regurgitation were identified, by multivariable ordinal longitudinal methods. Results Tricuspid regurgitation 1 week after annuloplasty was 3+ or 4+ in 14% of patients. Regurgitation severity was stable across time with the Carpentier-Edwards Ring ( P = .7), increased slowly with the Cosgrove-Edwards band ( P = .05), and rose more rapidly with the De Vega ( P = .002) and Peri-Guard ( P = .0009) procedures. Risk factors for worsening regurgitation included higher preoperative regurgitation grade, poor left ventricular function, permanent pacemaker, and repair type other than Ring annuloplasty. Right ventricular systolic pressure, Ring size, preoperative New York Heart Association functional class, and concomitant surgery were not risk factors. Tricuspid reoperation was rare (3% at 8 years), and hospital mortality after reoperation was 37%. Conclusions Tricuspid valve annuloplasty did not consistently eliminate functional regurgitation, and across time regurgitation increased importantly after Peri-Guard and De Vega annuloplasties. Therefore, these repair techniques should be abandoned, and transtricuspid pacing leads should be replaced with epicardial leads.
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Recurrent mitral regurgitation after annuloplasty for functional ischemic mitral regurgitation
The Journal of thoracic and cardiovascular surgery, 2004Co-Authors: Edwin C. Mcgee, Eugene H. Blackstone, Jeevanantham Rajeswaran, A. Marc Gillinov, Bruce W. Lytle, Takahiro Shiota, Joseph F Sabik, Gideon Cohen, Farzad Najam, Patrick M MccarthyAbstract:Objectives We sought to characterize the temporal return of mitral regurgitation after annuloplasty for functional ischemic mitral regurgitation; to identify its predictors, particularly with respect to annuloplasty type; and to determine whether annuloplasty type influences survival. Methods From April 1985 through November 2002, 585 patients underwent annuloplasty alone for repair of functional ischemic mitral regurgitation, generally with concomitant coronary revascularization (95%). A flexible band (Cosgrove) was used in 68%, a Rigid Ring (Carpentier) in 21%, and bovine pericardial annuloplasty (Peri-Guard) in 11%. Six hundred seventy-eight postoperative echocardiograms were available in 422 patients to assess the time course of postoperative mitral regurgitation and its correlates. Most echocardiograms were performed early after the operation (median, 8 days); 17% were performed at 1 year or beyond. Results DuRing the first 6 months after repair, the proportion of patients with 0 or 1+ mitral regurgitation decreased from 71% to 41%, whereas the proportion with 3+ or 4+ regurgitation increased from 13% to 28% ( P P = .2), although Cosgrove bands were used in most patients receiving 26- and 28-mm annuloplasties. Freedom from reoperation was 97% at 5 years. Annuloplasty type was not associated with survival. Conclusions Although initial mitral valve replacement would eliminate the risk of postoperative mitral regurgitation, this strategy has been associated with reduced survival. Therefore the development of additional techniques is necessary to achieve more secure repair of functional ischemic mitral regurgitation.
Bruce W. Lytle - One of the best experts on this subject based on the ideXlab platform.
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Surgical management of secondary tricuspid valve regurgitation: annulus, commissure, or leaflet procedure?
The Journal of Thoracic and Cardiovascular Surgery, 2010Co-Authors: Jose L. Navia, Edward R. Nowicki, Eugene H. Blackstone, Nicolas Brozzi, Daniel E. Nento, Fernando A. Atik, Jeevanantham Rajeswaran, A. Marc Gillinov, Lars G. Svensson, Bruce W. LytleAbstract:Objectives Techniques employed today concomitantly with left-sided heart valve surgery address secondary tricuspid valve regurgitation at 3 anatomic levels—annulus, commissure, and leaflet—although success of these alone or in combination in eliminating tricuspid regurgitation is uncertain. Our objective was to assess the comparative effectiveness of these techniques in reducing or eliminating secondary tricuspid regurgitation. Methods From 1990 to 2008, 2277 patients underwent tricuspid valve procedures for secondary tricuspid regurgitation concomitantly with mitral (n = 1527, 67%), aortic (n = 180, 7.9%), or combined (n = 570, 25%) valve surgery. These included annulus (flexible prosthesis [n = 1052, 46%], Rigid prosthesis [standard = 387, 3-dimensional = 197; 26%], Peri-Guard annuloplasty [Synovis Surgical Innovations, St Paul, Minn; n = 185, 8.1%], and De Vega suture [n = 129, 5.7%]), commissure (Kay [n = 248, 11%]), and leaflet (edge-to-edge suture [n = 79, 3.5%] ± annulus or commissural) procedures. A total of 4745 postoperative transthoracic echocardiograms in 1965 patients were analyzed. Results By 3 months after surgery, only 32% of patients overall had no tricuspid regurgitation. However, by 5 years, this had decreased to 22%, and 3+/4+ tricuspid regurgitation had increased from 11% at 3 months to 17%. Patients with Rigid Ring annuloplasty alone, either standard or 3-dimensional, had the least increase of 3+/4+ tricuspid regurgitation (to 12% at 5 years) compared with either a commissural or leaflet procedure. Conclusion Rigid prosthetic Ring annuloplasty, standard or 3-dimensional, provides early and sustained reduction of tricuspid regurgitation secondary to left-sided valve disease without need for an additional leaflet procedure. However, results are imperfect, possibly because other anatomic levels (subvalvular, papillary muscle, and right ventricular) contributing to its pathophysiology are unaddressed.
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tricuspid valve repair durability and risk factors for failure
The Journal of Thoracic and Cardiovascular Surgery, 2004Co-Authors: Patrick M Mccarthy, Jeevanantham Rajeswaran, Bruce W. Lytle, Sunil K Bhudia, Katherine J Hoercher, Delos M Cosgrove, Eugene H. BlackstoneAbstract:Abstract Objectives To compare durability of tricuspid valve annuloplasty techniques, identify risk factors for repair failure, and characterize survival, reoperation, and functional class of surviving patients. Methods From 1990 to 1999, 790 patients (mean age 65 ± 12 years, 51% New York Heart Association functional class III or IV, and mean right ventricular systolic pressure 56 ± 18 mm Hg) underwent tricuspid valve annuloplasty for functional regurgitation using 4 techniques: Carpentier-Edwards semi-Rigid Ring, Cosgrove-Edwards flexible band, De Vega procedure, and customized semicircular Peri-Guard annuloplasty. Of these patients, 89% had concomitant mitral valve surgery. A total of 2245 follow-up transthoracic echocardiograms were retrieved. Tricuspid regurgitation was analyzed, and risk factors for worsening regurgitation were identified, by multivariable ordinal longitudinal methods. Results Tricuspid regurgitation 1 week after annuloplasty was 3+ or 4+ in 14% of patients. Regurgitation severity was stable across time with the Carpentier-Edwards Ring ( P = .7), increased slowly with the Cosgrove-Edwards band ( P = .05), and rose more rapidly with the De Vega ( P = .002) and Peri-Guard ( P = .0009) procedures. Risk factors for worsening regurgitation included higher preoperative regurgitation grade, poor left ventricular function, permanent pacemaker, and repair type other than Ring annuloplasty. Right ventricular systolic pressure, Ring size, preoperative New York Heart Association functional class, and concomitant surgery were not risk factors. Tricuspid reoperation was rare (3% at 8 years), and hospital mortality after reoperation was 37%. Conclusions Tricuspid valve annuloplasty did not consistently eliminate functional regurgitation, and across time regurgitation increased importantly after Peri-Guard and De Vega annuloplasties. Therefore, these repair techniques should be abandoned, and transtricuspid pacing leads should be replaced with epicardial leads.
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Recurrent mitral regurgitation after annuloplasty for functional ischemic mitral regurgitation
The Journal of thoracic and cardiovascular surgery, 2004Co-Authors: Edwin C. Mcgee, Eugene H. Blackstone, Jeevanantham Rajeswaran, A. Marc Gillinov, Bruce W. Lytle, Takahiro Shiota, Joseph F Sabik, Gideon Cohen, Farzad Najam, Patrick M MccarthyAbstract:Objectives We sought to characterize the temporal return of mitral regurgitation after annuloplasty for functional ischemic mitral regurgitation; to identify its predictors, particularly with respect to annuloplasty type; and to determine whether annuloplasty type influences survival. Methods From April 1985 through November 2002, 585 patients underwent annuloplasty alone for repair of functional ischemic mitral regurgitation, generally with concomitant coronary revascularization (95%). A flexible band (Cosgrove) was used in 68%, a Rigid Ring (Carpentier) in 21%, and bovine pericardial annuloplasty (Peri-Guard) in 11%. Six hundred seventy-eight postoperative echocardiograms were available in 422 patients to assess the time course of postoperative mitral regurgitation and its correlates. Most echocardiograms were performed early after the operation (median, 8 days); 17% were performed at 1 year or beyond. Results DuRing the first 6 months after repair, the proportion of patients with 0 or 1+ mitral regurgitation decreased from 71% to 41%, whereas the proportion with 3+ or 4+ regurgitation increased from 13% to 28% ( P P = .2), although Cosgrove bands were used in most patients receiving 26- and 28-mm annuloplasties. Freedom from reoperation was 97% at 5 years. Annuloplasty type was not associated with survival. Conclusions Although initial mitral valve replacement would eliminate the risk of postoperative mitral regurgitation, this strategy has been associated with reduced survival. Therefore the development of additional techniques is necessary to achieve more secure repair of functional ischemic mitral regurgitation.
Patrick M Mccarthy - One of the best experts on this subject based on the ideXlab platform.
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tricuspid valve repair durability and risk factors for failure
The Journal of Thoracic and Cardiovascular Surgery, 2004Co-Authors: Patrick M Mccarthy, Jeevanantham Rajeswaran, Bruce W. Lytle, Sunil K Bhudia, Katherine J Hoercher, Delos M Cosgrove, Eugene H. BlackstoneAbstract:Abstract Objectives To compare durability of tricuspid valve annuloplasty techniques, identify risk factors for repair failure, and characterize survival, reoperation, and functional class of surviving patients. Methods From 1990 to 1999, 790 patients (mean age 65 ± 12 years, 51% New York Heart Association functional class III or IV, and mean right ventricular systolic pressure 56 ± 18 mm Hg) underwent tricuspid valve annuloplasty for functional regurgitation using 4 techniques: Carpentier-Edwards semi-Rigid Ring, Cosgrove-Edwards flexible band, De Vega procedure, and customized semicircular Peri-Guard annuloplasty. Of these patients, 89% had concomitant mitral valve surgery. A total of 2245 follow-up transthoracic echocardiograms were retrieved. Tricuspid regurgitation was analyzed, and risk factors for worsening regurgitation were identified, by multivariable ordinal longitudinal methods. Results Tricuspid regurgitation 1 week after annuloplasty was 3+ or 4+ in 14% of patients. Regurgitation severity was stable across time with the Carpentier-Edwards Ring ( P = .7), increased slowly with the Cosgrove-Edwards band ( P = .05), and rose more rapidly with the De Vega ( P = .002) and Peri-Guard ( P = .0009) procedures. Risk factors for worsening regurgitation included higher preoperative regurgitation grade, poor left ventricular function, permanent pacemaker, and repair type other than Ring annuloplasty. Right ventricular systolic pressure, Ring size, preoperative New York Heart Association functional class, and concomitant surgery were not risk factors. Tricuspid reoperation was rare (3% at 8 years), and hospital mortality after reoperation was 37%. Conclusions Tricuspid valve annuloplasty did not consistently eliminate functional regurgitation, and across time regurgitation increased importantly after Peri-Guard and De Vega annuloplasties. Therefore, these repair techniques should be abandoned, and transtricuspid pacing leads should be replaced with epicardial leads.
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Recurrent mitral regurgitation after annuloplasty for functional ischemic mitral regurgitation
The Journal of thoracic and cardiovascular surgery, 2004Co-Authors: Edwin C. Mcgee, Eugene H. Blackstone, Jeevanantham Rajeswaran, A. Marc Gillinov, Bruce W. Lytle, Takahiro Shiota, Joseph F Sabik, Gideon Cohen, Farzad Najam, Patrick M MccarthyAbstract:Objectives We sought to characterize the temporal return of mitral regurgitation after annuloplasty for functional ischemic mitral regurgitation; to identify its predictors, particularly with respect to annuloplasty type; and to determine whether annuloplasty type influences survival. Methods From April 1985 through November 2002, 585 patients underwent annuloplasty alone for repair of functional ischemic mitral regurgitation, generally with concomitant coronary revascularization (95%). A flexible band (Cosgrove) was used in 68%, a Rigid Ring (Carpentier) in 21%, and bovine pericardial annuloplasty (Peri-Guard) in 11%. Six hundred seventy-eight postoperative echocardiograms were available in 422 patients to assess the time course of postoperative mitral regurgitation and its correlates. Most echocardiograms were performed early after the operation (median, 8 days); 17% were performed at 1 year or beyond. Results DuRing the first 6 months after repair, the proportion of patients with 0 or 1+ mitral regurgitation decreased from 71% to 41%, whereas the proportion with 3+ or 4+ regurgitation increased from 13% to 28% ( P P = .2), although Cosgrove bands were used in most patients receiving 26- and 28-mm annuloplasties. Freedom from reoperation was 97% at 5 years. Annuloplasty type was not associated with survival. Conclusions Although initial mitral valve replacement would eliminate the risk of postoperative mitral regurgitation, this strategy has been associated with reduced survival. Therefore the development of additional techniques is necessary to achieve more secure repair of functional ischemic mitral regurgitation.
Jeevanantham Rajeswaran - One of the best experts on this subject based on the ideXlab platform.
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Surgical management of secondary tricuspid valve regurgitation: annulus, commissure, or leaflet procedure?
The Journal of Thoracic and Cardiovascular Surgery, 2010Co-Authors: Jose L. Navia, Edward R. Nowicki, Eugene H. Blackstone, Nicolas Brozzi, Daniel E. Nento, Fernando A. Atik, Jeevanantham Rajeswaran, A. Marc Gillinov, Lars G. Svensson, Bruce W. LytleAbstract:Objectives Techniques employed today concomitantly with left-sided heart valve surgery address secondary tricuspid valve regurgitation at 3 anatomic levels—annulus, commissure, and leaflet—although success of these alone or in combination in eliminating tricuspid regurgitation is uncertain. Our objective was to assess the comparative effectiveness of these techniques in reducing or eliminating secondary tricuspid regurgitation. Methods From 1990 to 2008, 2277 patients underwent tricuspid valve procedures for secondary tricuspid regurgitation concomitantly with mitral (n = 1527, 67%), aortic (n = 180, 7.9%), or combined (n = 570, 25%) valve surgery. These included annulus (flexible prosthesis [n = 1052, 46%], Rigid prosthesis [standard = 387, 3-dimensional = 197; 26%], Peri-Guard annuloplasty [Synovis Surgical Innovations, St Paul, Minn; n = 185, 8.1%], and De Vega suture [n = 129, 5.7%]), commissure (Kay [n = 248, 11%]), and leaflet (edge-to-edge suture [n = 79, 3.5%] ± annulus or commissural) procedures. A total of 4745 postoperative transthoracic echocardiograms in 1965 patients were analyzed. Results By 3 months after surgery, only 32% of patients overall had no tricuspid regurgitation. However, by 5 years, this had decreased to 22%, and 3+/4+ tricuspid regurgitation had increased from 11% at 3 months to 17%. Patients with Rigid Ring annuloplasty alone, either standard or 3-dimensional, had the least increase of 3+/4+ tricuspid regurgitation (to 12% at 5 years) compared with either a commissural or leaflet procedure. Conclusion Rigid prosthetic Ring annuloplasty, standard or 3-dimensional, provides early and sustained reduction of tricuspid regurgitation secondary to left-sided valve disease without need for an additional leaflet procedure. However, results are imperfect, possibly because other anatomic levels (subvalvular, papillary muscle, and right ventricular) contributing to its pathophysiology are unaddressed.
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tricuspid valve repair durability and risk factors for failure
The Journal of Thoracic and Cardiovascular Surgery, 2004Co-Authors: Patrick M Mccarthy, Jeevanantham Rajeswaran, Bruce W. Lytle, Sunil K Bhudia, Katherine J Hoercher, Delos M Cosgrove, Eugene H. BlackstoneAbstract:Abstract Objectives To compare durability of tricuspid valve annuloplasty techniques, identify risk factors for repair failure, and characterize survival, reoperation, and functional class of surviving patients. Methods From 1990 to 1999, 790 patients (mean age 65 ± 12 years, 51% New York Heart Association functional class III or IV, and mean right ventricular systolic pressure 56 ± 18 mm Hg) underwent tricuspid valve annuloplasty for functional regurgitation using 4 techniques: Carpentier-Edwards semi-Rigid Ring, Cosgrove-Edwards flexible band, De Vega procedure, and customized semicircular Peri-Guard annuloplasty. Of these patients, 89% had concomitant mitral valve surgery. A total of 2245 follow-up transthoracic echocardiograms were retrieved. Tricuspid regurgitation was analyzed, and risk factors for worsening regurgitation were identified, by multivariable ordinal longitudinal methods. Results Tricuspid regurgitation 1 week after annuloplasty was 3+ or 4+ in 14% of patients. Regurgitation severity was stable across time with the Carpentier-Edwards Ring ( P = .7), increased slowly with the Cosgrove-Edwards band ( P = .05), and rose more rapidly with the De Vega ( P = .002) and Peri-Guard ( P = .0009) procedures. Risk factors for worsening regurgitation included higher preoperative regurgitation grade, poor left ventricular function, permanent pacemaker, and repair type other than Ring annuloplasty. Right ventricular systolic pressure, Ring size, preoperative New York Heart Association functional class, and concomitant surgery were not risk factors. Tricuspid reoperation was rare (3% at 8 years), and hospital mortality after reoperation was 37%. Conclusions Tricuspid valve annuloplasty did not consistently eliminate functional regurgitation, and across time regurgitation increased importantly after Peri-Guard and De Vega annuloplasties. Therefore, these repair techniques should be abandoned, and transtricuspid pacing leads should be replaced with epicardial leads.
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Recurrent mitral regurgitation after annuloplasty for functional ischemic mitral regurgitation
The Journal of thoracic and cardiovascular surgery, 2004Co-Authors: Edwin C. Mcgee, Eugene H. Blackstone, Jeevanantham Rajeswaran, A. Marc Gillinov, Bruce W. Lytle, Takahiro Shiota, Joseph F Sabik, Gideon Cohen, Farzad Najam, Patrick M MccarthyAbstract:Objectives We sought to characterize the temporal return of mitral regurgitation after annuloplasty for functional ischemic mitral regurgitation; to identify its predictors, particularly with respect to annuloplasty type; and to determine whether annuloplasty type influences survival. Methods From April 1985 through November 2002, 585 patients underwent annuloplasty alone for repair of functional ischemic mitral regurgitation, generally with concomitant coronary revascularization (95%). A flexible band (Cosgrove) was used in 68%, a Rigid Ring (Carpentier) in 21%, and bovine pericardial annuloplasty (Peri-Guard) in 11%. Six hundred seventy-eight postoperative echocardiograms were available in 422 patients to assess the time course of postoperative mitral regurgitation and its correlates. Most echocardiograms were performed early after the operation (median, 8 days); 17% were performed at 1 year or beyond. Results DuRing the first 6 months after repair, the proportion of patients with 0 or 1+ mitral regurgitation decreased from 71% to 41%, whereas the proportion with 3+ or 4+ regurgitation increased from 13% to 28% ( P P = .2), although Cosgrove bands were used in most patients receiving 26- and 28-mm annuloplasties. Freedom from reoperation was 97% at 5 years. Annuloplasty type was not associated with survival. Conclusions Although initial mitral valve replacement would eliminate the risk of postoperative mitral regurgitation, this strategy has been associated with reduced survival. Therefore the development of additional techniques is necessary to achieve more secure repair of functional ischemic mitral regurgitation.
Ajc Antoine Schmeitz - One of the best experts on this subject based on the ideXlab platform.
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an improved magic formula swift tyre model that can handle inflation pressure changes
Vehicle System Dynamics, 2010Co-Authors: Ajc Antoine Schmeitz, Hans B PacejkaAbstract:This paper describes extensions to the widely used TNO MF-Tyre 5.2 Magic Formula tyre model. The Magic Formula itself has been adapted to cope with large camber angles and inflation pressure changes. In addition, the description of the rolling resistance has been improved. Modelling of the tyre dynamics has been changed to allow a seamless and consistent switch from simple first-order relaxation behaviour to Rigid Ring dynamics. Finally, the effect of inflation pressure on the loaded radius and the tyre enveloping properties is discussed and some results are given to illustrate the capabilities of the model.
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The MF-Swift tyre model : extending the Magic Formula with Rigid Ring dynamics and an enveloping model
Jsae Review, 2005Co-Authors: Hans B Pacejka, Ajc Antoine Schmeitz, S.t.h. JansenAbstract:The Magic Formula tyre model is typically used in vehicle handling simulations. This paper summarises developments which extend the validity range of the Magic Formula to higher frequencies, short wavelength excitation and rolling over arbitrary three dimensional obstacles. This new tyre model has been validated extensively using experimental results which show that the extended demands can be met. Examples are given, illustrating that the new tyre model can be used successfully in areas normally not associated with a Magic Formula tyre model.
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application of a semi empirical dynamic tyre model for rolling over arbitrary road profiles
International Journal of Vehicle Design, 2004Co-Authors: Ajc Antoine Schmeitz, Hans B Pacejka, S.t.h. Jansen, J C Davis, N N Kota, C G Liang, Gabriel LodewijksAbstract:The application of the Rigid Ring tyre model, in combination with a new enveloping model with elliptical cams, mounted in a quarter vehicle system is described for both specific obstacles, like potholes and bumps, and measured road profiles that fit the general category of "broad-band random signals". Validation results of both the tyre and vehicle models are presented. In addition, the models are analysed extensively to obtain insight into how the vehicle system behaves and to investigate how the enveloping model that generates an effective road surface contributes to this behaviour.
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full vehicle abs braking using the swift Rigid Ring tyre model
Control Engineering Practice, 2000Co-Authors: J Pauwelussen, S.t.h. Jansen, L Gootjes, C Schroder, K U Kohne, Ajc Antoine SchmeitzAbstract:In recent years, at the Delft University of Technology and TNO-Automotive and in conjunction with an industrial consortium, a pragmatic tyre model has been developed going by the name SWIFT, which is geared to the analysis of tyre oscillations and its effects on vehicle behaviour. The SWIFT tyre model has been designed to cover in-plane, out-of-plane and combined higher order dynamic tyre performance. It can be regarded as an extension of the Magic Formula pragmatic tyre model, up to a range of at least about 70 Hz. This paper describes the application of the SWIFT tyre model to full vehicle ABS braking. First, the model is used to derive the single tyre response to road undulations and brake torque step input, both being very much of relevance to ABS braking. This includes a survey of the sensitivity of the dynamic tyre parameters regarding the first, Rigid belt, eigenfrequencies and the relative damping. Next, the response of a quarter vehicle to similar input is discussed with specific emphasis on the added value of the dynamic characteristics of the SWIFT model in comparison to steady state and transient tyre models. Finally, full vehicle ABS controlled braking on an even road is considered for various road friction values and vehicle speed.
